Hormones and Longevity: The Complete Guide to Your Body's Aging Signals

Not every hormonal change of aging needs treatment, and not every treatment that raises a hormone level improves health. The sections below summarise what trials and large studies show for each major hormone.

Testosterone: The Male Longevity Hormone

In the Baltimore Longitudinal Study of Aging, total testosterone and the free testosterone index both declined with age in healthy men, independently of other health factors, and total testosterone was also lower with higher body mass index. By total-testosterone criteria, low levels affected about 20% of men over 60, 30% over 70 and 50% over 80, and even more by free testosterone criteria.¹ Aging and low testosterone share reduced bone and lean mass, lower muscle strength and more total and abdominal fat.¹

The TRAVERSE trial, published in 2023, enrolled 5,246 men aged 45 to 80 with symptoms of hypogonadism, low testosterone and existing or high risk of cardiovascular disease, and randomized them to testosterone gel or placebo. Over a mean follow-up of 33 months, major cardiovascular events occurred in 7.0% of the testosterone group and 7.3% of the placebo group (hazard ratio 0.96), meeting the trial's test of noninferiority.³ Atrial fibrillation, acute kidney injury and pulmonary embolism were more common with testosterone. It was designed to test safety, not to show that testosterone prevents disease.

The Endocrine Society recommends diagnosing hypogonadism only in men with symptoms and signs of testosterone deficiency and unequivocally, consistently low testosterone, confirmed with repeated fasting morning measurements. When treatment starts, it aims for testosterone in the mid-normal range, with a monitoring plan that covers symptoms, side effects, testosterone and hematocrit levels and, in the first year, prostate cancer risk. The guideline recommends against starting testosterone in men planning fertility soon or with breast or prostate cancer, a palpable prostate nodule or a PSA above 4 ng/mL.²

Estradiol: The Female Longevity Hormone

The menopause transition brings a large fall in estradiol. Hormone therapy remains the most effective treatment for hot flashes and the genitourinary syndrome of menopause, and it prevents bone loss and fracture.⁷ In cell and animal models, estradiol protects neurons, partly by stabilising mitochondria, but these are laboratory findings, not evidence of benefit in women.⁴

Our HRT article covers the evidence in detail. In short, the 2022 Menopause Society statement finds hormone therapy's benefit-risk ratio favourable under 60 or within 10 years of menopause and less favourable when started later, because of greater absolute risks of heart disease, stroke, blood clots and dementia, and its risks differ by type, dose, duration, route and timing.⁷

Growth Hormone and IGF-1: Somatopause

Growth hormone secretion from the pituitary, and the IGF-1 it drives, decline with age, a change sometimes called somatopause.⁵ Trials of growth hormone in healthy older people tested whether reversing it helps. On average, treatment reduced fat mass by about 2.1 kg and increased lean mass by about 2.1 kg without changing bone density, but people were more likely to develop soft-tissue swelling, joint pain, carpal tunnel syndrome and breast enlargement, and somewhat more likely to develop diabetes.⁸ The reviewers concluded that growth hormone cannot be recommended as an anti-aging therapy, and distributing it for that purpose is illegal in the United States.⁸

Lower growth hormone and IGF-1 signalling extends lifespan in several animal models. In people the evidence is narrower: among 184 people in their nineties, women with IGF-1 below the median lived longer but men did not, and lower IGF-1 predicted longer survival in those with a history of cancer.⁹

Thyroid: The Metabolic Regulator

Thyroid hormones set the metabolic rate of nearly every cell. In pooled data from 11 cohorts with 55,287 adults, 6.2% had subclinical hypothyroidism, a raised TSH (4.5 to 19.9 mIU/L) with normal thyroxine.¹⁰ The risk of heart disease events and deaths rose with higher TSH, particularly at 10 mIU/L or more, but total mortality was not increased.¹⁰ Whether to treat a mildly raised TSH is a decision to make with your clinician.

DHEA and Cortisol: The Stress Axis

DHEA-S, the main circulating form of the adrenal hormone DHEA, falls with age, and cortisol is the body's main stress hormone. This guide does not suggest DHEA doses or cortisol-lowering supplements.

Derek Giordano

Founder & Editor, IQ Healthspan

Derek Giordano is the founder and editor of IQ Healthspan. A father of four with a lifelong interest in athletics, fitness and the supplement industry, he built the site to show what the research actually supports. Derek is not a physician: articles cite peer-reviewed studies with numbered references you can check, and corrections are logged publicly. Articles are researched, drafted and fact-checked with the help of AI tools, and every claim is checked against the studies it cites. IQ Healthspan has no supplement brand partnerships, affiliate relationships or financial conflicts of interest.

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Sources Listed With Numbered Citations

10 references at the end of this article, checked against PubMed; studies link to their PubMed record