Men
Testosterone and Aging
Testosterone falls slowly with age, and weight gain is linked to drops as big as a decade of aging. Very low levels go with higher death rates.
Testosterone gets talked about like a fuel gauge: full at 25, blinking by 50, with a clinic ad ready to top you up. The research on testosterone and aging describes something slower and messier, and that difference matters for anyone thinking about living longer and better. Humanic Blue separates that age pattern from the sales pitch.
Testosterone does fall with age, but gradually. In a National Institute on Aging study, low readings showed up in about 1 in 5 men over 60 and half of men over 80. Weight and life changes can matter about as much as birthdays, according to a Boston study: a gain of 4 to 5 points in body mass index (BMI), a weight-to-height measure, went with a drop similar to about 10 years of aging. Very low levels are linked to higher death rates, though a link can’t show cause. No trial has shown that raising testosterone helps men live longer.
In This Article
- Testosterone falls slowly, and low readings pile up after 60
- Weight and health are linked to drops as big as aging itself
- Sexual symptoms showed a more consistent link in the European study
- Very low levels go with higher death rates
- What a big safety trial of testosterone gel did and didn’t test
- The studies and numbers behind all of this
Key Takeaways
- The National Institute on Aging study found a gradual testosterone decline with age, including in healthy men.
- The Massachusetts study linked weight gain and some life changes to drops about as large as a decade of aging; it did not establish cause.
- In the European study, sexual symptoms had the most consistent pattern of association with low testosterone.
- Very low testosterone is linked to higher death rates; ordinary low-normal levels weren’t, once other health factors were counted. The pooled analysis found an association, not proof that testosterone caused the deaths.
- The trials discussed here do not establish whether raising testosterone helps men live longer.
How much does testosterone fall with age?
In the Baltimore Longitudinal Study of Aging, researchers at the National Institute on Aging measured testosterone repeatedly in stored blood samples from the men in the study. Their 2001 report found that total testosterone fell by an average of about 0.12 nmol/L (about 3.6 ng/dL) a year, and their free testosterone index fell too. That index divides total testosterone by a blood protein that carries it; it estimates unbound testosterone rather than directly measuring it.
The decline showed up regardless of illness and medication use. By the standard total-testosterone cutoff, about 20% of men over 60 had low levels, 30% over 70 and 50% over 80. Using the free testosterone index, the shares were higher. The Baltimore figures
A low value isn’t a diagnosis. The Endocrine Society’s 2018 guideline reserves the diagnosis of hypogonadism, a condition involving inadequate testosterone production, for men with symptoms plus testosterone that is clearly and consistently low, confirmed with repeat fasting morning tests. Testing is covered in What Are the Symptoms of Low Testosterone?
Age, weight and health
Age isn’t working alone. In the Massachusetts Male Aging Study, researcher Thomas Travison and colleagues at the New England Research Institutes followed Boston-area men, aged 40 to 70 at the start, from the late 1980s into the early 2000s. A rise of 4 to 5 BMI points, or the loss of a spouse, went with a fall in testosterone similar to about 10 years of aging.
The team concluded that, over the short to medium term, health and lifestyle may be linked to falling testosterone as strongly as aging itself is. In plainer words, the calendar is only part of the story.
The European Male Aging Study adds detail. In a 2008 analysis of men aged 40 to 79 in eight countries, led by endocrinologist Frederick Wu of the University of Manchester, men with obesity had total testosterone about 5 nmol/L (about 147 ng/dL) lower than men at a healthy weight. Age and weight also seemed to act through different routes: age mainly through the testes, obesity mainly through hormone signals from the brain.
The authors noted that these risk factors can potentially be changed. Both studies are observational, though, and neither tested whether losing weight brings testosterone back up. How the two studies compare
What would help separate an age-related testosterone pattern from the effects of weight and health?
Which symptoms track with low testosterone?
Fatigue, low mood and low energy are often blamed on testosterone. When the European Male Aging Study team examined men for a 2010 New England Journal of Medicine study, those symptoms were related to testosterone levels, but loosely.
Only three sexual symptoms, poor morning erections, low sexual desire and erectile dysfunction, rose together as testosterone fell in a pattern consistent enough to define a condition. The researchers proposed defining late-onset hypogonadism as all three sexual symptoms plus low total and free testosterone. The proposed cutoffs
What low levels predict
A 2024 analysis in the Annals of Internal Medicine, led by endocrinologist Bu Yeap of the University of Western Australia, pooled individual records from nine long-term studies covering about 20,600 men. Hormones were measured by mass spectrometry, a more accurate lab method, and men were followed for at least five years.
After accounting for age, weight, smoking, health conditions and other factors, testosterone in the ordinary range wasn’t linked to death rates. Only men with very low levels had higher risk: below 7.4 nmol/L (213 ng/dL) for death from any cause, and below 5.3 nmol/L (153 ng/dL) for death from heart disease and stroke.
The authors listed their observational design as a limitation. Very low testosterone could be a marker of illness rather than a cause of it. Funding included government grants and philanthropic donations from Lawley Pharmaceuticals, a Perth company that sells topical testosterone products; the paper says funders had no role in the analysis. More on the pooled analysis
What has raising testosterone actually shown?
The TRAVERSE trial, led by Cleveland Clinic cardiologist A. Michael Lincoff and published in the New England Journal of Medicine in 2023, randomly assigned men aged 45 to 80 to testosterone gel or a placebo gel. All had symptoms, two low fasting testosterone tests, and heart disease or high heart risk.
Over about three years, about 7% of men in each group experienced the combined outcome: a first nonfatal heart attack, nonfatal stroke or cardiovascular death. Testosterone met the trial’s preset limit for ruling out a large increase in that outcome; this does not prove identical risks or exclude smaller differences. Atrial fibrillation (an irregular heart rhythm), sudden kidney injury and blood clots in the lungs were more common with testosterone.
The trial was funded by AbbVie, which made the AndroGel testosterone gel at the time, and other testosterone makers, and several authors worked for AbbVie. It tested heart safety, not whether therapy helps men live longer. The FDA’s 2025 labeling changes are covered in the symptoms article, and testosterone therapy’s wider benefits and risks are covered in their own article in this series. Trial details
What separates the risks associated with low testosterone from the effects of raising it?
What’s Interesting
In the Massachusetts study, losing a spouse went with about the same testosterone drop as a decade of aging, and so did a gain of 4 to 5 BMI points. That’s an association, not a mechanism, and the study didn’t explain it. But it’s a reminder that a hormone often discussed like engine oil also tracks with life as it’s lived.
It also changes the question a lab result raises, from “how old am I?” to “what else is going on?”
What This Means in Practice
For men focused on living longer and better, the Endocrine Society’s guideline treats a confirmed low number as a reason to look for causes, not just a figure to raise. Results come from large groups of men, and one man’s number can mean something different depending on his age, weight and health.
- Symptoms first. The Endocrine Society ties diagnosis to symptoms plus consistently low levels. In the European study, sexual symptoms were the most specific ones.
- Morning, fasting, repeated. The Endocrine Society recommends fasting morning tests and a repeat test to confirm a low result.
- Look for causes. The same guideline recommends further evaluation to find the cause of confirmed deficiency. Weight, illness and life events all showed up in the studies above.
- Very low levels stand out. In the pooled analysis, only very low levels were linked to higher death rates.
- Ask about the risks of therapy, including the atrial fibrillation and lung clots seen in TRAVERSE.
A primary care clinician can order and interpret testing. An endocrinologist or urologist can evaluate confirmed low testosterone.
Bottom Line
Testosterone falls gradually with age, and low readings become common after 60. Weight gain and other life changes are linked to drops as large as a decade of aging. In the European study, sexual symptoms showed a more consistent link to low levels than fatigue or low mood. Very low testosterone is associated with higher death rates, but the studies can’t show cause. TRAVERSE met its preset safety limit for the combined outcome of nonfatal heart attack, nonfatal stroke or cardiovascular death in men with confirmed deficiency and heart disease or high heart risk; smaller differences remained possible and other risks rose, and no trial has tested whether therapy extends life. Open questions remain, including whether weight loss restores testosterone enough to matter; a primary care clinician or endocrinologist can help place a result in context.
A NOTE FROM LONGEVITY365
We read research, consult expert perspectives and work to make complicated health information easier to understand. What you’re reading here reflects how we’ve interpreted and organized that information. It is educational content—not personal medical advice, diagnosis or treatment guidance.
We’re not perfect, and neither is the available research. Evidence changes, new studies emerge and what’s appropriate for one person may not be appropriate for another.
Use this article as a starting point for your own research and conversations with qualified professionals. Always talk with your doctor or another trusted healthcare professional before making decisions that could affect your health, particularly if you take medications, are receiving treatment, have existing health conditions, are pregnant or have other circumstances that could affect what’s appropriate for you.
Reader Questions
A few questions to carry into the comments or your next conversation. Please leave out identifying or personal medical details.
- 01After reading this, what would you want a test result to actually help you decide?
- 02How does observing low testosterone alongside illness differ from testing whether raising testosterone improves health?
- 03What would you ask a clinician, lab, or qualified professional before letting a number change a health decision?
Extra Insights & Sources
For readers who want the details behind each claim above.
What We Know
- Testosterone declines gradually with age in healthy men. Established.
- Weight gain and other health and life changes are linked to substantially lower testosterone. Supported (observational).
- Sexual symptoms are the most specific signs of low testosterone. Supported.
- Very low testosterone is associated with higher all-cause and cardiovascular mortality. Supported (observational).
- In men with diagnosed deficiency and high cardiac risk, testosterone met TRAVERSE’s preset safety limit for the combined cardiovascular outcome; smaller differences were not excluded. Supported (one large randomized controlled trial, or RCT).
What We Don’t Know
- Whether low testosterone causes higher mortality or reflects illness. Unknown.
- Whether weight loss restores testosterone enough to matter for symptoms. Uncertain.
- Whether testosterone therapy extends lifespan. Unknown. No trial has tested it.
How much it falls: the Baltimore data
Harman and colleagues at the National Institute on Aging measured total testosterone and sex hormone-binding globulin (SHBG), a protein that carries testosterone in blood, by radioimmunoassay, a laboratory measurement method, in stored samples from 890 men in the Baltimore Longitudinal Study of Aging (Journal of Clinical Endocrinology & Metabolism, 2001). After correcting for sample-date effects, they found an average change of −0.124 nmol/L per year in total testosterone and −0.0049 nmol T/nmol SHBG per year in the free testosterone index, a ratio of total testosterone to SHBG used to estimate unbound testosterone. Total testosterone, but not the free testosterone index, also fell with higher BMI. The authors reported that the declines didn’t depend on health factors. By total testosterone criteria, low (hypogonadal) levels rose to about 20% of men over 60, 30% over 70 and 50% over 80, with even higher percentages by free testosterone index criteria. Here nmol/L and ng/dL are different units of hormone concentration. The ng/dL figure is our conversion (0.124 × 28.84 ≈ 3.6).
Age, weight and health: two studies
Massachusetts Male Aging Study (2007). Travison and colleagues (Journal of Clinical Endocrinology & Metabolism) followed 1,667 randomly selected Boston-area men aged 40 to 70 at baseline (1987–1989), with follow-up visits in 1995–1997 (947 men) and 2002–2004 (584 men). They found substantial declines in total and free testosterone with aging alone, and reported that a 4 to 5 kg/m² rise in body mass index, or the loss of a spouse, was associated with a fall in total testosterone comparable to about 10 years of aging. Funding: US National Institutes of Health (NIA and NIDDK grants).
European Male Aging Study (2008). Wu and colleagues (Journal of Clinical Endocrinology & Metabolism) analyzed a baseline cross-sectional survey of 3,200 community-dwelling men aged 40 to 79 in eight European countries. The survey captures one point in time, so it shows associations, not change within the same men.
The table uses LH for luteinizing hormone, a signal that tells the testes to make testosterone. The hypothalamus and pituitary are parts of the brain’s hormone-control system. Both pmol/L and nmol/L express amounts per liter: 1 nmol/L equals 1,000 pmol/L. A larger number in pmol/L therefore need not mean a larger concentration. The final column reports the researchers’ proposed explanations, rather than established causes.
| Factor | Effect on testosterone | Suggested mechanism |
|---|---|---|
| Age | Free testosterone 3.12 pmol/L lower per year | Impaired testicular function (LH raised) |
| Overweight (BMI 25–29.9) | Total testosterone 2.32 nmol/L lower; free 17.60 pmol/L lower | Hypothalamus/pituitary (LH unchanged or lower) |
| Obesity (BMI 30+) | Total testosterone 5.09 nmol/L lower (about 147 ng/dL); free 53.72 pmol/L lower | Hypothalamus/pituitary (LH unchanged or lower) |
| Other illness | Total testosterone 0.80 nmol/L lower | LH unchanged in younger men, higher in older men |
| Smoking | Total testosterone 1.31 nmol/L higher, free testosterone not | Higher SHBG changing the hormone feedback signals |
Weight comparisons are against men with a BMI under 25. The ng/dL conversion is ours.
The authors concluded that because these risk factors are potentially modifiable, they point to possible ways of preventing testosterone from falling as men age. The two studies measured different things (a per-year change within men in Massachusetts; one-time differences between men in Europe), so their numbers aren’t directly comparable.
Which symptoms track: the 2010 EMAS study
Wu and colleagues surveyed a random sample of 3,369 men aged 40 to 79 at eight European centers (New England Journal of Medicine, 2010), measuring morning total testosterone by mass spectrometry. Poor morning erection, low sexual desire, erectile dysfunction, inability to perform vigorous activity, depression and fatigue were all significantly related to testosterone. But only the three sexual symptoms showed a syndromic association with lower testosterone, meaning they clustered together as levels fell. The authors proposed that late-onset hypogonadism be defined by at least three sexual symptoms plus total testosterone below 11 nmol/L (3.2 ng/mL, or 320 ng/dL) and free testosterone below 220 pmol/L (64 pg/mL).
What low levels predict: the 2024 pooled analysis
Yeap and colleagues pooled individual records from studies that followed men living in the community over time with sex hormones measured by mass spectrometry and at least five years of follow-up. Nine studies provided individual data for 20,654 men (255,830 participant-years—the sum of each man’s observation time, not one man’s follow-up—7,241 deaths); 11 studies provided summary estimates (n = 24,109). After accounting for measured health differences, comparisons of five testosterone-level groups did not show a clear difference in death rates. The hazard ratio (HR), a comparison of the rate of death over time, and its 95% confidence interval (CI), a range expressing statistical uncertainty, were above 1.0 only below 7.4 nmol/L (213 ng/dL) for all-cause mortality and below 5.3 nmol/L (153 ng/dL) for cardiovascular mortality. A ratio of 1.0 means no difference between the compared groups. Low testosterone wasn’t linked to new cardiovascular events after accounting for the measured health differences. Listed limitations: “Observational study design, heterogeneity among studies, and imputation of missing data.” Those limitations include differences among studies and statistical estimates used to fill in missing information. The men were predominantly White, from Australia, Europe and North America.
Funding: Australia’s Medical Research Future Fund, the Government of Western Australia and “philanthropic donations by Lawley Pharmaceuticals to the University of Western Australia.” The paper states the funders had no role in data collection, analysis or writing, and the authors declared no conflicts in relation to the work. Lawley Pharmaceuticals, a Perth company founded in 1995, describes itself as developing “topical hormone therapies for use in women and men”; as of September 25, 2026, its product list includes two testosterone products, AndroFeme 1 and AndroForte 5.
What raising it has shown: TRAVERSE
TRAVERSE (Lincoff and colleagues, New England Journal of Medicine, 2023) was conducted at several centers, with men randomly assigned to testosterone or inactive gel. Neither the men nor investigators knew which gel each man received. Its noninferiority design required the upper confidence limit for the hazard ratio to stay below 1.5: it tested whether the data ruled out a 50% or greater relative increase in the rate of the combined primary outcome, rather than proving identical risks. It enrolled men aged 45 to 80 who had preexisting or a high risk of cardiovascular disease, reported symptoms of hypogonadism and had two fasting testosterone levels below 300 ng/dL. Men received daily 1.62% testosterone gel, dose-adjusted to keep testosterone between 350 and 750 ng/dL, or placebo gel. Mean treatment lasted 21.7 months and mean follow-up 33.0 months.
- Primary outcome (cardiovascular death, nonfatal heart attack or nonfatal stroke): 182 men (7.0%) with testosterone vs 190 (7.3%) with placebo; HR 0.96 (95% CI 0.78–1.17), meeting the trial’s prespecified noninferiority test. This does not exclude smaller differences or risks outside the measured outcome.
- Atrial fibrillation, acute kidney injury and pulmonary embolism were more frequent with testosterone.
- The paper states that it was funded by AbbVie and others, and several authors listed AbbVie affiliations. AndroGel was made at the time by AbbVie and is now marketed by Ascend Therapeutics, according to TIME, which also reported that the trial was required by the FDA and funded by a consortium of testosterone manufacturers.
Sources
- Harman SM, et al. Baltimore Longitudinal Study of Aging, Journal of Clinical Endocrinology & Metabolism, 2001: PubMed 11158037
- Travison TG, et al. Massachusetts Male Aging Study, Journal of Clinical Endocrinology & Metabolism, 2007: PubMed 17148559
- Wu FC, et al. European Male Aging Study, Journal of Clinical Endocrinology & Metabolism, 2008: PubMed 18270261
- Wu FC, et al. Late-onset hypogonadism, New England Journal of Medicine, 2010: PubMed 20554979
- Bhasin S, et al. Endocrine Society guideline, Journal of Clinical Endocrinology & Metabolism, 2018: PubMed 29562364
- Yeap BB, et al. Testosterone and mortality, Annals of Internal Medicine, 2024: PubMed 38739921
- Lincoff AM, et al. TRAVERSE, New England Journal of Medicine, 2023: PubMed 37326322
- TIME: Testosterone Treatments Aren’t Linked to Heart Risks When Patients Are Carefully Monitored
- Lawley Pharmaceuticals: Company site
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