{"product_id":"why-do-women-live-longer-than-men-the-brain-gonad-connection-explained","title":"Why Do Women Live Longer Than Men? The Brain-Gonad Connection Explained","description":"\u003cp\u003eWomen live longer than men in nearly every country and time period studied, yet this survival advantage does not hold true across all animal species — and the reasons why remain surprisingly mysterious. This review article explores the possibility that the answer lies in a complex hormonal conversation between the brain and the reproductive organs (gonads), known as the hypothalamic-pituitary-gonadal (HPG) axis. By examining studies in mice, flies, worms, dogs, and even historical records of human eunuchs, the author builds a case that lesser-known hormones in this brain-gonad dialogue — particularly activin, inhibin, and follistatin — may hold important clues to understanding why the sexes age differently and how longevity might be influenced.\u003c\/p\u003e\n\n\u003ch1\u003eWhy Do Women Live Longer Than Men? The Brain-Gonad Connection Explained\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eUnderstanding the Sex Difference in Lifespan\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#sex-differences\"\u003eSex Differences Across the Animal Kingdom\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#mouse-interventions\"\u003eSex-Specific Effects of Anti-Aging Treatments in Mice\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#gonad-connection\"\u003eThe Link Between Reproductive Organs and Longevity\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#brain-connection\"\u003eThe Brain's Role in Longevity\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#brain-gonad\"\u003eThe Brain-Gonad Dialogue: A New Frontier in Aging Research\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#clinical-implications\"\u003eWhat This Means for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eStudy Limitations\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIn humans, women live longer than men in nearly every country and time period studied, including every year in Iceland since 1840.\u003c\/li\u003e\n\u003cli\u003eIn mice, many genetic and drug interventions that extend lifespan affect only one sex, suggesting treatments may need tailoring by sex.\u003c\/li\u003e\n\u003cli\u003eIn a study of 297 castrated men and 735 intact men, castrated men lived 14 years longer, but the study was observational with imperfect controls.\u003c\/li\u003e\n\u003cli\u003eIn mice, four of six life-extending drugs worked only in males; rapamycin showed dose-dependent sex differences.\u003c\/li\u003e\n\u003cli\u003eThe most reliable ways to extend healthspan are healthy diet, regular activity, not smoking, limiting alcohol, and staying engaged.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eUnderstanding the Sex Difference in Lifespan\u003c\/h2\u003e\n\n\u003cp\u003eOne of the most robust features of human biology is that women live longer than men. This is not a recent trend or a quirk of modern medicine — it has been true throughout recorded history and in virtually all circumstances of human life.\u003c\/p\u003e\n\n\u003cp\u003eThe female survival advantage begins even before birth. Female babies are better survivors than male babies when born prematurely, according to studies published in 2008 and 2009. Women survive better than men in good times and bad — during famines, during epidemics, and during periods of peace and prosperity alike.\u003c\/p\u003e\n\n\u003cp\u003eA striking example comes from Iceland, where life expectancy has been tracked since 1840. During times of epidemic disease outbreaks, life expectancy dipped as low as 19 years; in recent years, it has been as high as 82 years. In \u003cstrong\u003eevery single year\u003c\/strong\u003e during that nearly 180-year span, female life expectancy exceeded male life expectancy.\u003c\/p\u003e\n\n\u003cp\u003eIn modern, technologically developed countries, women die at lower age-adjusted rates of almost all leading causes of death. This is a striking and consistent pattern.\u003c\/p\u003e\n\n\u003ch2 id=\"sex-differences\"\u003eSex Differences Across the Animal Kingdom\u003c\/h2\u003e\n\n\u003cp\u003eGiven how consistent the female survival advantage is in humans, it might come as a surprise that females do not outlive males in every species — not even in all mammals.\u003c\/p\u003e\n\n\u003cp\u003eMales are clearly the longer-lived sex in:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eGuinea pigs\u003c\/li\u003e\n  \u003cli\u003eGolden hamsters\u003c\/li\u003e\n  \u003cli\u003eAt least some bat species\u003c\/li\u003e\n  \u003cli\u003eSeveral South American monkey species\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eAmong intact (non-neutered) dogs, males are also slightly longer-lived than females, according to a 2018 study. In other species, there may be no consistent longevity difference between the sexes at all, even though individual studies often show one sex living longer.\u003c\/p\u003e\n\n\u003cp\u003eConsider laboratory mice. An analysis of \u003cstrong\u003e118 mouse longevity studies\u003c\/strong\u003e that included both sexes found a remarkable range of outcomes. In the most extreme study, males lived nearly \u003cstrong\u003e50% longer\u003c\/strong\u003e than females. In another study, females lived as much as \u003cstrong\u003e30% longer\u003c\/strong\u003e than males. Overall, there was a continuum of differences between these two extremes — meaning the \"which sex lives longer\" answer in mice depends heavily on conditions.\u003c\/p\u003e\n\n\u003cp\u003eEven within a single inbred mouse genotype — the commonly used C57BL\/6 mouse — researchers found nearly as broad a range of survival differences between the sexes across 29 available studies as across all mouse genotypes combined. The conditions that favor survival of one sex over the other in mice remain unknown, but if they could be discovered, they would go a long way toward explaining why these differences exist.\u003c\/p\u003e\n\n\u003cp\u003eThis pattern of condition-dependent survival advantage is also seen in other laboratory species:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIn fruit flies (\u003cem\u003eDrosophila melanogaster\u003c\/em\u003e), survival differences depend on genotype, mating status, female fecundity (reproductive capacity), and whether the opposite sex is present. Under some combinations, males have been reported to live as much as \u003cstrong\u003e3.8 times longer\u003c\/strong\u003e than females; under other combinations, females lived \u003cstrong\u003e2.3 times longer\u003c\/strong\u003e than males.\u003c\/li\u003e\n  \u003cli\u003eIn the nematode worm (\u003cem\u003eCaenorhabditis elegans\u003c\/em\u003e), individually housed males live \u003cstrong\u003e10–20% longer\u003c\/strong\u003e than hermaphrodites (the two worm \"sexes\" are males and hermaphrodites). However, when groups of worms — whether all male or mixed sex — are cultured together, the sex difference in survival disappears.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"mouse-interventions\"\u003eSex-Specific Effects of Anti-Aging Treatments in Mice\u003c\/h2\u003e\n\n\u003cp\u003eFor decades, the only intervention that reliably lengthened life and extended health in laboratory rodents was dietary restriction, and its effects seemed to affect both sexes approximately equally. The first genetic intervention that lengthened life in mice also appeared to benefit both sexes equally. But as more and more genes extending mouse longevity were discovered, a surprising pattern began to emerge: \u003cstrong\u003esex-specific effects were common\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003eHere are some of the key genetic findings, which reveal a striking pattern of sex-specific longevity effects:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIGF-1 receptor haploinsufficiency\u003c\/strong\u003e (having only one working copy of the gene) increases longevity in female mice but \u003cstrong\u003enot in males\u003c\/strong\u003e (Bokov et al. 2011; Holzenberger et al. 2003).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInsulin receptor haploinsufficiency\u003c\/strong\u003e, on the other hand, increases longevity in male mice but \u003cstrong\u003enot in females\u003c\/strong\u003e (Nelson et al. 2012).\u003c\/li\u003e\n  \u003cli\u003eKnocking out \u003cstrong\u003eIRS1\u003c\/strong\u003e or \u003cstrong\u003eS6K1\u003c\/strong\u003e lengthened lifespan in females only (Selman et al. 2008, 2009).\u003c\/li\u003e\n  \u003cli\u003eDouble haploinsufficiency of \u003cstrong\u003emTOR and mlst8\u003c\/strong\u003e (a component of both mTOR complexes) also lengthened lifespan in females only (Lamming et al. 2012).\u003c\/li\u003e\n  \u003cli\u003eDisrupting \u003cstrong\u003eprotein kinase A\u003c\/strong\u003e enhanced longevity in males but not females (Enns et al. 2009).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOverexpressing Sirt6\u003c\/strong\u003e (a protein deacetylase) enhanced longevity in males but not females (Kanfi et al. 2012).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe fact that disabling a single gene copy produces sex-specific effects is hard to explain — after all, if one copy of a gene is disabled, it should be equally disabled in both sexes. Yet the evidence clearly shows these manipulations often affect one sex and not the other.\u003c\/p\u003e\n\n\u003ch3\u003eDrugs That Extend Lifespan Also Show Sex Differences\u003c\/h3\u003e\n\n\u003cp\u003ePutative senescence-retarding (anti-aging) drugs have also proven to be sex-specific remarkably often. This is somewhat easier to imagine than with genetic manipulations, because sex differences in how drugs are processed by the body (pharmacokinetics) are well known. Still, the commonness of such effects in life-extending drugs administered to mice is rather stunning.\u003c\/p\u003e\n\n\u003cp\u003eThe National Institute on Aging's Interventions Testing Program (ITP) evaluates drugs for their impact on mouse longevity at three independent sites. Of \u003cstrong\u003esix drugs\u003c\/strong\u003e that extended life in mice:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4 drugs\u003c\/strong\u003e — aspirin, nordihydroguaiaretic acid (NDGA), 17-α-estradiol, and Protandim® — extended lifespan \u003cstrong\u003eonly in males\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1 drug\u003c\/strong\u003e — acarbose — had a much larger effect in males than females\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1 drug\u003c\/strong\u003e — rapamycin — showed sex specificity that was \u003cstrong\u003edose-dependent\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe rapamycin results are particularly instructive. Rapamycin, which had the largest effect on longevity of any drug tested, showed a clear dose-dependent pattern of sex differences. The table below summarizes the findings:\u003c\/p\u003e\n\n\u003ctable border=\"1\" cellpadding=\"6\" cellspacing=\"0\"\u003e\n  \u003ctr\u003e\n    \u003cth\u003eRapamycin Dose\u003c\/th\u003e\n    \u003cth\u003eMale Effect (% change in median longevity)\u003c\/th\u003e\n    \u003cth\u003eFemale Effect (% change in median longevity)\u003c\/th\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e4.7 ppm* in food\u003c\/td\u003e\n    \u003ctd\u003e3%\u003c\/td\u003e\n    \u003ctd\u003e16%\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e14 ppm* in food\u003c\/td\u003e\n    \u003ctd\u003e13%\u003c\/td\u003e\n    \u003ctd\u003e21%\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e42 ppm* in food\u003c\/td\u003e\n    \u003ctd\u003e23%\u003c\/td\u003e\n    \u003ctd\u003e26%\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e126 ppm¶ in food\u003c\/td\u003e\n    \u003ctd\u003e14%\u003c\/td\u003e\n    \u003ctd\u003e9%\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e8 mg\/kg¶ daily injections\u003c\/td\u003e\n    \u003ctd\u003e14%\u003c\/td\u003e\n    \u003ctd\u003e0%\u003c\/td\u003e\n  \u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003cp\u003e\u003cem\u003e*ppm = parts per million in food, given from 9 months of age throughout life. ¶ Concentration in food or daily injections for 90 days beginning at age 20–21 months. Percentages represent change in median longevity calculated from birth.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe lower the food concentration of rapamycin, the greater the sex difference favoring females in longevity extension. Notably, the sex-biased longevity enhancement was \u003cstrong\u003enot\u003c\/strong\u003e related to sex differences in the blood concentration of rapamycin between the sexes (Miller et al. 2014) — meaning the different effects were not simply a matter of males and females absorbing different amounts of the drug.\u003c\/p\u003e\n\n\u003cp\u003eA different study by Bitto et al. (2016) used another approach: beginning rapamycin treatment — either by daily injection or in food — when mice were already old (20–21 months of age) and continuing it for only 90 days. When calculated from the time treatment began, the researchers observed a \u003cstrong\u003e45% increase in median male longevity\u003c\/strong\u003e and a \u003cstrong\u003e39% increase in median female longevity\u003c\/strong\u003e when feeding the high dose of rapamycin (equivalent to 14% and 9% when calculated from birth).\u003c\/p\u003e\n\n\u003cp\u003eWith rapamycin injections — which the authors estimated was equivalent to \u003cstrong\u003e27 times\u003c\/strong\u003e the dose originally reported to extend life when administered in food — males lived a whopping \u003cstrong\u003e61% longer\u003c\/strong\u003e from the time of first injection compared with controls. Somewhat surprisingly, \u003cstrong\u003eno change in median female longevity\u003c\/strong\u003e was seen with this treatment.\u003c\/p\u003e\n\n\u003cp\u003eRegardless of treatment dose, route of administration, or timing, clear sex differences were apparent in every rapamycin study. Understanding how these differences are affected by dose, route, and timing will be critical to understanding the mechanism(s) of its impact on longevity.\u003c\/p\u003e\n\n\u003ch2 id=\"gonad-connection\"\u003eThe Link Between Reproductive Organs and Longevity\u003c\/h2\u003e\n\n\u003cp\u003eConsistently, important features of sex differences in longevity have to do with reproduction or reproductive capability. Animals that reproduce are typically shorter-lived than animals that do not. Evolutionary biologists term this the \u003cstrong\u003e\"cost of reproduction\"\u003c\/strong\u003e (Harshman and Zera 2007).\u003c\/p\u003e\n\n\u003cp\u003eIt is well known among animal breeders that too much reproduction by females will shorten life. What is less well known is that \u003cstrong\u003emating itself shortens male lifespan\u003c\/strong\u003e in numerous species. The cost of mating is particularly well described in \u003cem\u003eDrosophila\u003c\/em\u003e flies:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eMating reduces longevity in both sexes of \u003cem\u003eD. melanogaster\u003c\/em\u003e (Chapman et al. 1995).\u003c\/li\u003e\n  \u003cli\u003eIn a different species, \u003cem\u003eD. subobscura\u003c\/em\u003e, unmated females live longer than males, but mating shortens female longevity more than male longevity — so mated males actually live longer than mated females (Maynard Smith 1958).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn modern humans, there does not appear to be any straightforward link between number of children and longevity. However, in a population of healthy centenarians — a genetically and socially homogeneous group of Ashkenazi Jewish centenarians selected for both their health and longevity — the picture looked different. These centenarians had \u003cstrong\u003efewer children\u003c\/strong\u003e, and had their children \u003cstrong\u003elater\u003c\/strong\u003e, than a similar group of non-longevous Ashkenazi Jews. The lower number of children and delayed reproduction were observed for \u003cstrong\u003eboth male and female centenarians\u003c\/strong\u003e (Tabatabaie et al. 2011).\u003c\/p\u003e\n\n\u003ch3\u003eWhat Happens When Reproductive Organs Are Removed?\u003c\/h3\u003e\n\n\u003cp\u003ePerhaps more interesting than the impact of reproduction on longevity is the impact of \u003cem\u003ereproductive capability\u003c\/em\u003e on longevity. \u003cstrong\u003eGonadectomy\u003c\/strong\u003e (surgical removal of the testes or ovaries) increases longevity of both males and females in many species, including dogs, cats, and humans.\u003c\/p\u003e\n\n\u003cp\u003eIn dogs and cats, the impact on longevity of gonadectomy in females is considerably larger than the sex difference itself — meaning removing a female dog's ovaries extends her life by more than the typical lifespan gap between male and female dogs.\u003c\/p\u003e\n\n\u003ch3\u003eHistorical Human Evidence: Castration and Longevity\u003c\/h3\u003e\n\n\u003cp\u003eHuman studies of gonadectomy and longevity deserve careful explanation, because no human studies have been specifically designed to evaluate the longevity impact of gonadectomy. All available studies are retrospective and observational, and the special circumstances in which people were gonadectomized make it difficult to determine the appropriate control population.\u003c\/p\u003e\n\n\u003cp\u003eA landmark study by Hamilton and Mestler (1969) obtained records from a Kansas institution for the mentally deficient, covering patients born between roughly 1870 and 1930:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eMen in this institution were castrated generally for \u003cstrong\u003ebehavioral reasons\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eWomen were ovariectomized in those pre-contraceptive days to \u003cstrong\u003eprevent unwanted pregnancies\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eControls were intact men and women from the same institution.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThese were not ideal controls, since there is no information on whether the control groups were treated differently than the surgically castrated group, or why some individuals were gonadectomized and others were not. But they were the best available comparison groups.\u003c\/p\u003e\n\n\u003cp\u003eThe results were striking. In a reasonably large sample of \u003cstrong\u003e297 castrated males\u003c\/strong\u003e compared with \u003cstrong\u003e735 intact males\u003c\/strong\u003e, median longevity of castrated males was an impressive \u003cstrong\u003e14 years longer\u003c\/strong\u003e — 69.3 years versus 55.7 years. Moreover, the earlier in life that men were castrated, the bigger the longevity difference compared with intact men.\u003c\/p\u003e\n\n\u003cp\u003eIn the much smaller sample of women (\u003cstrong\u003e23 ovariectomized versus 309 intact\u003c\/strong\u003e), there was no difference in survival. Median longevity for both groups was 65.2 years.\u003c\/p\u003e\n\n\u003cp\u003eA similarly large longevity difference was found in a study of \u003cstrong\u003eKorean eunuchs\u003c\/strong\u003e compared with other members of the Royal court (Min et al. 2012). Eunuchs — castrated males used as guards and servants in the Royal harem — had excellent genealogical records kept on members of the Royal courts, including birth and death dates, place of birth, court rank, names of wives, and adopted sons. Comparing the longevity of \u003cstrong\u003e81 eunuchs\u003c\/strong\u003e with intact men from three different Royal families, the eunuchs lived on average \u003cstrong\u003e14.4–19.1 years longer\u003c\/strong\u003e — data remarkably similar to the Kansas institution study. Thus, removing male gonadal hormones appears to have a significant impact on human health and longevity.\u003c\/p\u003e\n\n\u003ch3\u003eExceptions to the Pattern\u003c\/h3\u003e\n\n\u003cp\u003eOccasional exceptions to this general trend have been reported, and they are informative:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIn the \u003cstrong\u003eRottweiler dog breed\u003c\/strong\u003e, unlike dogs more generally, females are overrepresented by more than \u003cstrong\u003etwo-fold\u003c\/strong\u003e at extreme ages (defined as living ≥13 years, or roughly 30% beyond \"normal\" Rottweiler longevity). However, removal of ovaries within the first 4 years of life erases this female survival advantage (Waters et al. 2009).\u003c\/li\u003e\n  \u003cli\u003eRemoval of ovaries has also been reported to \u003cstrong\u003eshorten\u003c\/strong\u003e life in female CBA mice if done prior to sexual maturation (Cargill et al. 2003).\u003c\/li\u003e\n  \u003cli\u003eMore interestingly, those same researchers found that transplanting ovaries from young mice into \u003cstrong\u003e11-month-old post-reproductive mice\u003c\/strong\u003e restored estrus cyclicity (the mouse equivalent of a menstrual cycle) for several months and also led to a \u003cstrong\u003e40% increase in post-surgical longevity\u003c\/strong\u003e. No difference in maximum longevity was observed, however.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eDespite these rare exceptions, in general gonadal hormones appear to play an important role in longevity.\u003c\/p\u003e\n\n\u003ch2 id=\"brain-connection\"\u003eThe Brain's Role in Longevity\u003c\/h2\u003e\n\n\u003cp\u003eThe first single-gene mutation known to lengthen life in a mammal was the \u003cstrong\u003eAmes dwarf mouse\u003c\/strong\u003e mutation, which increased mean male and female longevity by a remarkable \u003cstrong\u003e49% and 68%\u003c\/strong\u003e, respectively (Brown-Borg et al. 1996).\u003c\/p\u003e\n\n\u003cp\u003eIronically, the gene responsible for Ames dwarfism was identified in the same year (1996). It was named \u003cstrong\u003eprop-1\u003c\/strong\u003e, a transcription factor involved in the development of the anterior pituitary (a master gland at the base of the brain). The Ames dwarf mutation eliminates the anterior pituitary cells responsible for producing:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProlactin (PRL)\u003c\/strong\u003e — a hormone involved in milk production and many other functions\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThyroid-stimulating hormone (TSH)\u003c\/strong\u003e — which regulates the thyroid gland\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGrowth hormone (GH)\u003c\/strong\u003e — which drives growth and metabolic regulation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eSeveral years later, it was discovered that the \u003cstrong\u003eSnell dwarf mouse\u003c\/strong\u003e, which has a defective \u003cem\u003epit-1\u003c\/em\u003e gene, was also long-lived. Pit-1 is also a transcription factor involved in anterior pituitary development. Snell dwarf mice were deficient in the same hormones as the Ames dwarf mice and displayed a very similar phenotype, including extending life in both sexes. The role of the prop-1 gene appears to be confined to turning on pit-1 in the pituitary.\u003c\/p\u003e\n\n\u003cp\u003eIronically, the pituitary had long been suspected of being a master regulator responsible for many aspects of physiology, including longevity (Everitt 1973). It was then discovered that eliminating \u003cstrong\u003eGH activity\u003c\/strong\u003e by inactivating its receptor also produced small mice with extended life in both sexes (Coschigano et al. 2000).\u003c\/p\u003e\n\n\u003cp\u003eFurther implicating GH in life extension, mice with a defective growth-hormone-releasing hormone receptor — which leads to a circulating level of GH of only \u003cstrong\u003e1% of controls\u003c\/strong\u003e — also exhibit extended life in both sexes (Flurkey et al. 2001). It has been assumed that it was the deficiency in \u003cstrong\u003eGH\u003c\/strong\u003e, rather than in TSH or prolactin, that was responsible for much (if not all) of the longevity effects observed in both Ames and Snell dwarf mice.\u003c\/p\u003e\n\n\u003ch3\u003eThe GH-IGF-1 Connection\u003c\/h3\u003e\n\n\u003cp\u003eOne of the key effects of GH secretion is that it stimulates secretion of \u003cstrong\u003eIGF-1\u003c\/strong\u003e (insulin-like growth factor 1) from the liver. It was soon reported that mice haploinsufficient in IGF-1 were also long-lived — but in this case, the effect was significant \u003cstrong\u003eonly in females\u003c\/strong\u003e (Holzenberger et al. 2003). A second study found a similar result, although the female longevity effect was much smaller (Bokov et al. 2011).\u003c\/p\u003e\n\n\u003cp\u003eSurprisingly, despite the fact that genetically reducing IGF-1 activity has a considerably smaller longevity effect than GH inactivation — and the fact that IGF-1's effects are sex-specific while GH inactivation affects both sexes — it is still commonly assumed that the GH longevity effect is largely due to its impact on IGF-1. The author notes that further investigation of the downstream effects of GH dynamics is clearly warranted.\u003c\/p\u003e\n\n\u003ch3\u003eBrain-Specific Insulin Signaling\u003c\/h3\u003e\n\n\u003cp\u003eAnother genetic manipulation reported to extend mouse life is reduced brain-specific signaling of the \u003cstrong\u003einsulin receptor substrate 2 (IRS2)\u003c\/strong\u003e (Taguchi et al. 2007). IRS2 is found throughout the body, but a global reduction in IRS2 signaling has been reported to lead to about the same increase in longevity (~14%) as does brain-specific reduction in signaling.\u003c\/p\u003e\n\n\u003cp\u003eUnfortunately, survival results were not broken out by sex in that study. However, this result could not be replicated in a second study (Selman et al. 2008) — a difference that may have to do with small differences in the diets used in the two studies. In that second study, reduced signaling of \u003cstrong\u003eIRS1\u003c\/strong\u003e did lengthen life, but in \u003cstrong\u003efemales only\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003cp\u003eJust as with gonadal hormones, brain-derived hormones clearly play a role in modulating aging and longevity.\u003c\/p\u003e\n\n\u003ch2 id=\"brain-gonad\"\u003eThe Brain-Gonad Dialogue: A New Frontier in Aging Research\u003c\/h2\u003e\n\n\u003cp\u003eReproduction in vertebrates involves a complex hormonal dialog between the brain and gonads. Given the empirical relationships between gonadal hormones and longevity, and between neuroendocrine activity and longevity, it makes sense to hypothesize that \u003cstrong\u003elongevity itself may be at least a partial consequence of this hormonal interplay\u003c\/strong\u003e between the gonads and brain — the hypothalamic-pituitary-gonadal (HPG) axis.\u003c\/p\u003e\n\n\u003cp\u003eAn interesting feature of the HPG axis is that the \u003cstrong\u003esame hormones occur in both sexes\u003c\/strong\u003e, but their tempo (timing), amount, tissue specificity, and activity differ. That might help explain some of the clear and pervasive sex differences in aging and longevity. Another feature is that the hormones involved all have pleiotropic (multi-effect) \u003cstrong\u003enon-reproductive effects\u003c\/strong\u003e in multiple tissues, as might be expected if they play major roles in aging.\u003c\/p\u003e\n\n\u003cp\u003eThis is not a new idea. Sex differences in the prevalence or rate of progression of specific age-related diseases have been hypothesized to result from gonadal hormones and their impact on neuroendocrine signaling for decades. For instance:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eMore women than men die from \u003cstrong\u003eAlzheimer's disease\u003c\/strong\u003e, even after adjusting for age (Austad 2017; Xu et al. 2016).\u003c\/li\u003e\n  \u003cli\u003eOne long-standing hypothesis is that this difference is due to age-related changes in gonadal steroids — particularly \u003cstrong\u003eestrogen\u003c\/strong\u003e, but also \u003cstrong\u003etestosterone\u003c\/strong\u003e (Pike 2017).\u003c\/li\u003e\n  \u003cli\u003eHowever, empirical evidence for this hypothesis has been mixed at best.\u003c\/li\u003e\n  \u003cli\u003eMore recent hypotheses suggest that \u003cstrong\u003egonadotropins\u003c\/strong\u003e — particularly \u003cstrong\u003eluteinizing hormone (LH)\u003c\/strong\u003e — may play a role in Alzheimer's pathogenesis (Webber et al. 2007).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe HPG hormone hypothesis of longevity modulation suggests that it may be the \u003cstrong\u003etotal package\u003c\/strong\u003e of HPG hormones that matters. For that to be valid, one would expect HPG hormones to be found and active in multiple non-reproductive tissues.\u003c\/p\u003e\n\n\u003cp\u003eThat has long been known to be true for gonadal steroids. Androgen and estrogen receptors are found in virtually every tissue. But it is also true for the gonadotropins, which — as gonadal steroid levels wane in later life — become \u003cstrong\u003eelevated\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLH receptors\u003c\/strong\u003e, in addition to their presence in ovaries and testes, are found in the \u003cstrong\u003eskin, breast, adrenals, retina, and brain\u003c\/strong\u003e (Ascoli et al. 2002).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFollicle-stimulating hormone (FSH)\u003c\/strong\u003e has receptors not only in ovaries and testes, but also in the \u003cstrong\u003eendothelium\u003c\/strong\u003e (blood vessel lining), \u003cstrong\u003emonocytes\u003c\/strong\u003e (immune cells), \u003cstrong\u003ebone\u003c\/strong\u003e, and \u003cstrong\u003efat\u003c\/strong\u003e (Lizneva et al. 2019).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eActivins, Inhibins, and Follistatin: The Lesser-Known Players\u003c\/h3\u003e\n\n\u003cp\u003ePossibly the most interesting of the lesser-known hormones in this regard are \u003cstrong\u003eactivins and inhibins\u003c\/strong\u003e — both members of the TGFβ protein superfamily — which, along with \u003cstrong\u003efollistatin\u003c\/strong\u003e, are best known for helping regulate FSH synthesis and secretion from the pituitary, as well as for modulating the effects of gonadotropins in the gonads (Baccarelli et al. 2001).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eActivin\u003c\/strong\u003e is produced in both gonads and pituitary, where it has its canonical (primary, well-established) effect of increasing FSH production and activity. But it is also expressed in:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThe heart\u003c\/li\u003e\n  \u003cli\u003eThe lungs\u003c\/li\u003e\n  \u003cli\u003eThe kidneys\u003c\/li\u003e\n  \u003cli\u003eThe gastrointestinal tract\u003c\/li\u003e\n  \u003cli\u003eMuscle\u003c\/li\u003e\n  \u003cli\u003eBone\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn these tissues, activin plays roles in cell proliferation, differentiation, metabolism, and apoptosis (programmed cell death), as well as in immune response and wound healing (Chen et al. 2006; Werner and Alzheimer 2006). In mammals, \u003cstrong\u003eactivin A\u003c\/strong\u003e (one of two major isoforms) appears to be \u003cstrong\u003eneuroprotective\u003c\/strong\u003e (Bloise et al. 2019). In flies, activin has even been reported to interact with insulin signaling to \u003cstrong\u003eimprove muscle performance and extend life\u003c\/strong\u003e (Bai et al. 2013).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eInhibins\u003c\/strong\u003e (there are two major isoforms) generally antagonize (counteract) the effects of activins (Makanji et al. 2014). Their primary site of production is the gonads, but inhibin is also found at much smaller concentrations in the:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAdrenal glands\u003c\/li\u003e\n  \u003cli\u003eBone\u003c\/li\u003e\n  \u003cli\u003eEye\u003c\/li\u003e\n  \u003cli\u003eLung\u003c\/li\u003e\n  \u003cli\u003eKidney\u003c\/li\u003e\n  \u003cli\u003ePituitary\u003c\/li\u003e\n  \u003cli\u003eSpleen\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn addition to its canonical reproductive role of inhibiting FSH, inhibin appears to play a role in \u003cstrong\u003ebone turnover\u003c\/strong\u003e (the continuous process of bone breakdown and rebuilding) and \u003cstrong\u003ehematopoiesis\u003c\/strong\u003e (the production of blood cells).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFollistatin\u003c\/strong\u003e, like inhibins, also inhibits FSH. Its primary production site is in the gonads — particularly the ovary — although it is also present in small amounts in virtually every tissue (Zhang et al. 2018). Follistatin is an inhibitor of multiple members of the TGFβ superfamily, most potently activin, which is how it has its impact on FSH and reproduction. Beyond that, follistatin also inhibits:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMyostatin\u003c\/strong\u003e — a protein that limits muscle growth\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBone morphogenetic protein (BMP)\u003c\/strong\u003e — involved in bone and tissue development\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn tissues, follistatin helps inhibit inappropriate cell proliferation and appears to function in the response to several kinds of stressors, including \u003cstrong\u003eoxidative and energetic stresses\u003c\/strong\u003e (Zhang et al. 2018). To the extent that these features of follistatin are valid, its potential impacts on longevity and aging could be substantial.\u003c\/p\u003e\n\n\u003cp\u003eIn conclusion, sex differences in aging and longevity are pervasive and still poorly understood. One potentially productive approach to a better understanding of these differences may be to focus specifically on the hormones involved in the \u003cstrong\u003eHPG axis\u003c\/strong\u003e — the full orchestra of the brain-gonad conversation, not just the famous players.\u003c\/p\u003e\n\n\u003ch2 id=\"clinical-implications\"\u003eWhat This Means for Patients\u003c\/h2\u003e\n\n\u003cp\u003eThis review article does not report new clinical trial data in humans, but its findings have several important implications for patients and for future medical research:\u003c\/p\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSex matters in medicine.\u003c\/strong\u003e The fact that so many genetic and drug interventions affect longevity differently in male and female mice suggests that treatments for age-related diseases may need to be tailored by sex. What works for one sex may not work — or may even harm — the other.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe reproductive system and aging are deeply connected.\u003c\/strong\u003e The historical data on eunuchs living 14–19 years longer, and on castrated men in a Kansas institution living 14 years longer, suggest that gonadal hormones have powerful effects on human health and lifespan. However, these findings do \u003cstrong\u003enot\u003c\/strong\u003e mean that people should seek gonadectomy — the side effects and quality-of-life implications would be enormous, and the studies are observational and potentially confounded.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRapamycin research is actively exploring sex-specific dosing.\u003c\/strong\u003e The dose-dependent sex differences seen in rapamycin studies could eventually lead to sex-specific dosing recommendations if the drug is ever approved for longevity or age-related disease indications in humans.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLesser-known hormones may be future drug targets.\u003c\/strong\u003e Activin, inhibin, and follistatin are involved in muscle maintenance, bone health, immune function, wound healing, and even neuroprotection. Drugs that modulate these pathways could potentially address multiple age-related problems at once.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2 id=\"limitations\"\u003eStudy Limitations\u003c\/h2\u003e\n\n\u003cp\u003eIt is important to recognize the limitations of the research described in this review:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMuch of the evidence comes from animal models.\u003c\/strong\u003e Mice, flies, and worms are not humans. While they share many biological pathways with humans, findings in these species frequently do not translate directly to human medicine.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe human gonadectomy studies are observational and retrospective.\u003c\/strong\u003e The Kansas institution study had imperfect control groups, and researchers had no information on why some individuals were gonadectomized and others were not. The Korean eunuch study had excellent genealogical records but a relatively small sample (81 eunuchs).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe \"cost of reproduction\" findings in centenarians were correlational.\u003c\/strong\u003e The Ashkenazi Jewish centenarians had fewer and later children than comparison subjects, but this does not prove that reproductive patterns caused their longevity — the association could be driven by other factors.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSex-specific findings in mice have not always been replicated.\u003c\/strong\u003e For example, the brain-specific IRS2 reduction finding could not be reproduced in a second study, possibly due to dietary differences.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe author presents a hypothesis\u003c\/strong\u003e — that the full package of HPG axis hormones, not just the well-known ones, modulates longevity — and notes that this idea requires much further investigation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients\u003c\/h2\u003e\n\n\u003cp\u003eBased on this research, here are some practical takeaways for patients interested in healthy aging:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBe cautious about supplements or drugs claiming anti-aging benefits.\u003c\/strong\u003e Even in controlled mouse studies, many treatments that extend lifespan work in only one sex. Claims that a product \"extends lifespan\" based on animal research may not apply to you.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaintain healthy reproductive hormone levels through lifestyle, not risky interventions.\u003c\/strong\u003e Regular exercise, adequate sleep, stress management, and a balanced diet all support healthy hormone function. Avoid unproven hormone therapies, which can have serious side effects.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStay tuned for sex-specific medicine.\u003c\/strong\u003e As research progresses, expect that doctors may increasingly consider your sex when recommending treatments for age-related conditions, from diabetes to Alzheimer's disease.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDiscuss menopause and andropause management with your doctor.\u003c\/strong\u003e The research highlights that gonadal hormones affect far more than reproduction — they influence bones, muscle, heart, immune function, and even the brain. If you are experiencing symptoms of hormonal changes, these can often be managed safely with medical guidance.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRemember the fundamentals.\u003c\/strong\u003e The most reliable ways to extend healthspan (the number of healthy years of life) remain a healthy diet, regular physical activity, not smoking, limiting alcohol, and staying socially and mentally engaged — regardless of your sex.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eDo women really live longer than men?\u003c\/h3\u003e\n\u003cp\u003eYes, in humans women live longer than men in nearly every country and time period studied. This advantage begins before birth, with female babies surviving premature birth better. In Iceland, tracked since 1840, female life expectancy exceeded male life expectancy every single year, even during epidemics and famines.\u003c\/p\u003e\n\u003ch3\u003eIs the female survival advantage true for all animals?\u003c\/h3\u003e\n\u003cp\u003eNo. Males outlive females in guinea pigs, golden hamsters, some bats, several South American monkeys, and among intact dogs. In lab mice, results vary widely: one study found males lived nearly 50% longer, another found females lived 30% longer. In fruit flies and worms, survival differences depend on conditions.\u003c\/p\u003e\n\u003ch3\u003eWhat did the study of castrated men find about longevity?\u003c\/h3\u003e\n\u003cp\u003eIn a study of 297 castrated men and 735 intact men at a Kansas institution, median longevity was 69.3 years for castrated men versus 55.7 years for intact men—a 14-year difference. Earlier castration was linked to a bigger difference. In a smaller group of 23 ovariectomized women, no survival difference was found.\u003c\/p\u003e\n\u003ch3\u003eDo anti-aging drugs work differently in males and females?\u003c\/h3\u003e\n\u003cp\u003eYes, in mice. Of six drugs that extended life, four—aspirin, NDGA, 17-α-estradiol, and Protandim—extended lifespan only in males. Acarbose had a much larger effect in males. Rapamycin showed dose-dependent sex differences: lower food doses favored females more, and daily injections benefited males but not females.\u003c\/p\u003e\n\u003ch3\u003eShould I consider castration or ovary removal to live longer?\u003c\/h3\u003e\n\u003cp\u003eNo. The human gonadectomy studies are observational and retrospective, with imperfect control groups, and do not prove cause and effect. The side effects and quality-of-life implications of removing gonads would be enormous. The article explicitly states these findings do not mean people should seek gonadectomy.\u003c\/p\u003e\n\u003ch3\u003eWhat are activin, inhibin, and follistatin?\u003c\/h3\u003e\n\u003cp\u003eThey are lesser-known hormones in the brain-gonad dialogue. Activin increases FSH production and is also found in heart, lungs, kidneys, muscle, and bone, where it affects cell growth and immune response. Inhibin counteracts activin. Follistatin inhibits activin, myostatin, and BMP, and helps respond to oxidative and energetic stress.\u003c\/p\u003e\n\u003ch3\u003eWhat can I do now to support healthy aging?\u003c\/h3\u003e\n\u003cp\u003eThe most reliable ways to extend healthspan remain a healthy diet, regular physical activity, not smoking, limiting alcohol, and staying socially and mentally engaged—regardless of sex. Maintain healthy reproductive hormone levels through lifestyle, not risky interventions. Discuss menopause or andropause symptoms with your doctor, and be cautious about anti-aging supplements or drugs.\u003c\/p\u003e\n\u003ch3\u003eIf I'm a woman considering hormone therapy for menopause symptoms, when should I seek a second opinion about how it might affect my long-term health?\u003c\/h3\u003e\n\u003cp\u003eGonadal hormones influence bone, muscle, heart, immune function, and the brain, not just reproduction, and sex-specific effects are common in aging research. Because treatments for age-related conditions may need tailoring by sex, and unproven hormone therapies carry serious side effects, a second opinion can help clarify whether a recommended hormonal approach fits your situation. Bring your hormone history, symptom records, and any prior test results. Discuss menopause management with your doctor, and consider independent expert review when advice feels uncertain. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal Article:\u003c\/strong\u003e \"Sex differences in health and aging: a dialog between the brain and gonad\"\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor:\u003c\/strong\u003e Steven N. Austad, Department of Biology, University of Alabama at Birmingham\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e GeroScience (2019) 41:267–273\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDOI:\u003c\/strong\u003e https:\/\/doi.org\/10.1007\/s11357-019-00081-3\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c\/strong\u003e This work was supported by the U.S. National Institutes of Health grants P30 AG050886, R01 AG057434, and R21 AG058811.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eThis patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace medical advice from a qualified healthcare provider.\u003c\/em\u003e\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47709982556316,"sku":null,"price":0.0,"currency_code":"RUB","in_stock":true}],"url":"https:\/\/diagnosticdetectives.ru\/products\/why-do-women-live-longer-than-men-the-brain-gonad-connection-explained","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}