A hormone produced primarily by the adrenal glands that serves as a precursor for testosterone and estrogen. Levels naturally peak in early adulthood and decline with age. Some research suggests maintaining healthy DHEA-S levels may support energy, immune function, and stress resilience, though evidence for supplementation remains mixed.

The primary estrogen during reproductive years, produced mainly by developing ovarian follicles. It regulates the menstrual cycle, supports bone and cardiovascular health, and affects mood and cognition. Levels fluctuate throughout the menstrual cycle (lowest during menstruation, peaking before ovulation) and decline significantly during menopause. Imbalances can cause irregular periods, fertility issues, mood changes, and various physical symptoms

The unbound, biologically active fraction of total testosterone that can interact with cellular receptors. This measurement provides insight into androgenic activity affecting metabolism, body composition, and various physiological functions.

A glycoprotein that regulates hormone bioavailability by binding to sex hormones in circulation. SHBG levels influence the amount of active hormones available to tissues and can reflect metabolic and endocrine health.

The primary male sex hormone responsible for sexual development, sperm production, muscle mass maintenance, bone density, and overall energy levels. Low levels can cause fatigue, reduced libido, erectile dysfunction, decreased muscle mass, and mood changes. Age-related decline is normal, but significant deficiency may warrant supplementation

FAI estimates the amount of active testosterone in the blood relative to binding proteins.