Three hormones worth testing at 40+.

We keep getting some version of the same question in reply, from both male and female subscribers. Should I get my hormones tested at 40?

Short honest answer. Yes. But not the panel most people get sold, and not for the reason it usually gets marketed. Three hormones matter for both sexes after 40. Cortisol pattern, thyroid full panel, and testosterone. The most heavily marketed hormone test at this age is the one for a diagnosis that does not exist.

The Endocrine Society is the international professional body for endocrinologists. Their explicit position on adrenal fatigue is that it is not a recognised medical diagnosis. A 2016 systematic review of 58 studies by Flavio Cadegiani and Claudio Kater in BMC Endocrine Disorders concluded there is no substantiation for the condition. The saliva and blood cortisol tests marketed to diagnose it are not scientifically validated for that purpose.

That does not mean the symptoms are imaginary. Persistent fatigue, low mood, and weight changes at 40+ are real. They tend to be caused by things that are diagnosable and directly treatable: primary adrenal insufficiency (Addison's), Cushing's syndrome, subclinical hypothyroidism, iron or B12 deficiency, sleep apnea, depression, or perimenopausal hormone shifts.

The consequence of the adrenal fatigue label, applied without ruling those out, is that a real diagnosable condition gets delayed for months or years while someone takes adaptogens and adrenal glandulars.

The first is the cortisol pattern. Not a single morning number, but a diurnal profile. Peak in the first hour after waking, decline through the day, low overnight. Flattening of that curve is the dysregulation worth watching for. Chronic stress can produce it. So can Cushing's or Addison's on either extreme.

The second is the thyroid full panel. Most GPs order TSH alone, which misses subclinical hypothyroidism (elevated TSH with still-normal free T4), Hashimoto's (needs TPO and TgAb antibodies), and low free T3 or elevated reverse T3 patterns. The full panel is TSH, free T4, free T3, reverse T3, and thyroid antibodies. Order these together or you are guessing.

The third is testosterone, and it applies to both sexes. In men, Henry Feldman and colleagues at the Massachusetts Male Aging Study, JCEM 2002, showed total testosterone declines about 0.8% per year and free testosterone about 2% per year from midlife on. This is well-known. What is not well-known is the equivalent finding in women. Sonia Davison and colleagues at Monash, JCEM 2005, tracked 1,423 women aged 18 to 75 and showed testosterone in women declines steadily with age from the 20s onward, largely independent of the menopause transition. The clinical implication for both sexes is the same. Low energy, low libido, lower muscle response to training, worse mood, worse cognition. The measurement worth requesting is total testosterone + free testosterone + SHBG (sex hormone binding globulin), which together give bioavailable testosterone.

For women in perimenopause, add estradiol and progesterone at the correct cycle phase. For men over 50, PSA and LH round out the picture.

Cortisol saliva panels sold as "adrenal stress index" are not validated. Adaptogen stacks marketed against adrenal fatigue treat a diagnosis that does not exist. If cortisol is genuinely dysregulated, sleep, load management, and time (or, in real endocrine disease, physician-managed replacement therapy) do the work. Not ashwagandha capsules.

Thyroid support supplements sold to raise low T3 do not survive clinical scrutiny. If your free T3 is low or your TSH is elevated, that is what an endocrinologist manages, not what a supplement stack fixes.

Testosterone boosters (tribulus, D-aspartic acid, most OTC stacks) do not meaningfully raise testosterone in men in randomised trials. What does: heavy resistance training, adequate protein, sleep, weight loss if carrying excess, and, in men with clinically low T and symptoms, physician-managed TRT. For women, resistance training and adequate protein carry the same weight. Testosterone therapy for women is a legitimate but specialist conversation, currently guided by the International Society for the Study of Women's Sexual Health position statement.

Ask for the panel, not the boosters. And ask for the full panel, not the TSH-only screen most GPs default to. The three that matter for both sexes at 40+ are the cortisol pattern, the thyroid full panel, and testosterone (total + free + SHBG). Add estradiol and progesterone for perimenopausal women, PSA and LH for men over 50.

Book the full-panel test. Most GPs will not order more than TSH and total testosterone without a specific request. The direct-to-consumer route is faster, more comprehensive, and often cheaper than out-of-pocket lab fees at a private clinic.

US: Function Health. $365 per year covers two blood draws per year at Quest Diagnostics labs, 160 biomarkers across 18 categories. Includes the full thyroid panel (TSH, free T3, free T4, reverse T3), sex hormones (testosterone total + free + SHBG, estradiol, DHEA-S), cortisol, comprehensive metabolic, cardiac, nutrient status, and autoimmune markers. Every panel is reviewed by a licensed physician on their clinical team and results are delivered with plain-language interpretation in the app. Founded by Dr. Mark Hyman. Andrew Huberman's “HUBERMAN” coupon code drops it to $315 per year.

Everywhere else: Google "DTC hormone blood test panel". Medichecks in the UK, iScreen in Australia, similar direct-to-consumer providers in most markets. Print this piece and take the marker list to a GP visit if you prefer that route.

Friday takes what to do once your results are back. How to read a hormone panel without panic, when to ask for a rerun, and where the actual intervention levers sit for each marker.

Until Friday.

Longevity Daily / The Building Decades