Longevity science: healthspan, biomarkers and what the evidence supports

What is healthspan, and how does it differ from lifespan?

Lifespan is how long a person lives. Healthspan is how long they live in good health: able to function, free of disabling disease. Longevity medicine aims to extend healthspan, and in practice it uses familiar tools earlier and more deliberately: tracking metabolic, cardiovascular and hormonal health over time, and choosing interventions against a patient's risks and goals.

The field mixes well-established clinical medicine with ideas that are still being tested. The most useful thing a clinician can bring to it is a clear view of which is which.

Biomarkers clinicians use to track aging

Most longevity work rests on biomarkers measured repeatedly over time rather than once: glucose and markers of insulin resistance, lipids and other cardiovascular risk markers, sex hormones and their binding protein, thyroid function, and body composition. The trend in one person usually says more than a single value against a population range.

Two cautions apply to every biomarker. First, a biomarker that moves is not the same as an outcome that improves; a change in a surrogate marker does not by itself show that a person will live longer or better. Second, measurement has limits. The Endocrine Society has noted, for example, that the very low estradiol concentrations relevant outside reproduction are too low to be measured accurately or precisely by routine methods.

Sources for this section: [1]

Protocol categories

Hormones and aging in men

Testosterone falls with age. Longitudinal cohorts, including the Massachusetts Male Aging Study and the Baltimore Longitudinal Study of Aging, followed the same men over years and found declines in total and free testosterone, with the share of men in the hypogonadal range rising in older age groups.

A falling level is not by itself a diagnosis. The Endocrine Society recommends diagnosing hypogonadism only in men with symptoms and signs and unequivocally, consistently low testosterone, confirmed with repeat fasting morning measurements. The American College of Physicians suggests discussing treatment for age-related low testosterone mainly in men with sexual dysfunction, on low-certainty evidence, and reassessing within twelve months. The European Menopause and Andropause Society advises against routine use in older men to improve physical function or cognition, for lack of data.

Sources for this section: [2], [3], [4], [5], [6]

Hormone protocols

Hormones, menopause and cardiometabolic risk in women

The menopause transition is a period of accelerating cardiovascular risk. The American Heart Association describes adverse changes over the transition in body composition, lipids and vascular health, and calls midlife a critical window for prevention. A meta-analysis of studies comparing premenopausal and postmenopausal women found less favorable lipid profiles after menopause, partly explained by age.

For symptoms, The North American Menopause Society's position is that hormone therapy is the most effective treatment for vasomotor symptoms and the genitourinary syndrome of menopause, and that its benefit-risk balance depends on age, time since menopause, type, dose, route and duration. On compounded "bioidentical" hormones, ACOG advises that they should not be prescribed routinely when FDA-approved formulations exist.

Sources for this section: [7], [8], [9], [10]

Peptides in aging: what the evidence shows

Peptides are short chains of amino acids, and some are approved medicines with full safety and efficacy review. Many others are marketed directly to patients without approval. A 2026 review of approved and unapproved peptides found that many unapproved compounds show favorable results in animal models, but that rigorous human safety data are scarce. A second 2026 review of peptides marketed to act on the growth hormone and IGF-1 axis reports adverse effects including endocrine and metabolic disturbances and fluid retention, alongside uncertainty about product composition and dosing in unregulated supply.

That is why Hormonaly's compound profiles state each peptide's regulatory status and grade the evidence, with animal-only evidence graded D.

Sources for this section: [11], [12]

Compound profiles · Peptide and hormone protocols

What the evidence supports, and what it does not

A short guide to where the evidence stands on common longevity questions, from the sources cited on this page.

• Supported: tracking cardiometabolic risk through midlife, and especially across the menopause transition.
• Supported, with conditions: testosterone therapy for men with symptoms and confirmed, consistently low levels; menopausal hormone therapy for bothersome symptoms, individualized by age and time since menopause.
• Not supported by current evidence: routine testosterone therapy in older men to improve physical function or cognition.
• Not supported: compounded bioidentical hormone therapy in place of FDA-approved formulations, absent a specific reason.
• Not established: "adrenal fatigue" as a diagnosis; a systematic review found no substantiation for it.
• Unknown in people: the long-term safety and benefit of most unapproved peptides, which rest largely on animal studies.
• Harmful: supraphysiologic use of performance-enhancing drugs, which the Endocrine Society links to cardiovascular, psychiatric, metabolic and endocrine harms.

Sources for this section: [7], [8], [4], [5], [9], [6], [10], [13], [11], [12], [14]

Frequently asked questions

References

1. Challenges to the measurement of estradiol: an endocrine society position statement. J Clin Endocrinol Metab. 2013. PMID: 23463657
2. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. J Clin Endocrinol Metab. 2002. PMID: 11836290
3. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab. 2001. PMID: 11158037
4. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018. PMID: 29562364
5. Testosterone Treatment in Adult Men With Age-Related Low Testosterone: A Clinical Guideline From the American College of Physicians. Ann Intern Med. 2020. PMID: 31905405
6. EMAS position statement: Testosterone replacement therapy in older men. Maturitas. 2023. PMID: 37845136
7. Menopause Transition and Cardiovascular Disease Risk: Implications for Timing of Early Prevention: A Scientific Statement From the American Heart Association. Circulation. 2020. PMID: 33251828
8. Lipid profile differences during menopause: a review with meta-analysis. Menopause. 2019. PMID: 31567869
9. The 2022 hormone therapy position statement of The North American Menopause Society. Menopause. 2022. PMID: 35797481
10. Compounded Bioidentical Menopausal Hormone Therapy: ACOG Clinical Consensus No. 6. Obstet Gynecol. 2023. PMID: 37856860
11. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. PMID: 41966639
12. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026. PMID: 42395176
13. Adrenal fatigue does not exist: a systematic review. BMC Endocr Disord. 2016. PMID: 27557747
14. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014. PMID: 24423981