Why Everyone Should Be Tracking Testosterone After 30 (Yes, Women Too!)

Testosterone begins quietly declining in your 30s, dropping 1 to 3% per year in both men and women. You might not notice it at first. Maybe you chalk up the fatigue to a demanding career, the slower recovery to getting older, the brain fog to stress. But this hormonal shift is one of the earliest and most overlooked drivers of biological aging, says Florence Comite, M.D., an endocrinologist, precision medicine expert, and author of Invincible

"We don't wake up one day with chronic disease or old age. It's beginning to brew in our 30s," Comite explained on a recent episode of the mindbodygreen podcast. "One of the biggest drivers is reduction in testosterone. It affects everything from metabolism to muscle, to insulin sensitivity, to mood, cognition, brain memory, and cardiovascular risk."

When you get a standard hormone lab panel, you'll typically see "total testosterone" listed. But that number can be misleading.

"The total testosterone is bound up in protein. It's not free to act," Comite says. What you really want to know is your free testosterone, which measures the amount of the hormone that's circulating and actively working in your system.

Here's where conventional medicine falls short. The reference ranges you see on a Quest or LabCorp report—typically 35 to 155 ng/dL for free testosterone—are based on population averages. And as Comite points out, those averages include a lot of people who are already metabolically unhealthy.

"By the time you hit your 40s, it would be rare to have a free testosterone over 100," she says. "Sometimes it's as low as 50, and 50 is what a boy who starts at puberty is at initially."

Optimal free testosterone for men, according to Comite, is 180 to 250 ng/dL. That's the range associated with peak metabolic function, muscle maintenance, cognitive sharpness, and cardiovascular health.

Many people think of testosterone as a uniquely male hormone, Comite says, but that's not true. Women produce it too, and it plays a critical role in energy, mood, muscle maintenance, and sexual function. Research reinforces this2, concluding that testosterone is "unquestionably a normal female hormone" with important physiological effects beyond sexual health.

If testing reveals low free testosterone, there are several paths forward, most of which involve some form of hormone replacement therapy (HRT). You may think of HRT as something for women in menopause, but proven to be very effective in men as well. A trial published in 20243 found that testosterone replacement therapy improved sexual activity, desire, and hypogonadal symptoms in men with low testosterone, with benefits sustained at 24 months.

Comite's top HRT recommendation for men is HCG (human chorionic gonadotropin), a peptide hormone that stimulates the cells in the testes that produce testosterone.

"It's only injectable," she explains. "You take it as a tiny shot twice a week because you want to create a pulsatile [rhythmic] atmosphere in the body. That's what really triggers the release of testosterone most effectively."

Testosterone creams are also on the market, but Comite is less enthusiastic about them for men. "It passes through the skin and can turn into estrogen or another hormone called dihydrotestosterone," she says, "and both of them can affect the body in a way you might not want."

While Comite has been taking testosterone for 30 years, she notes that it hasn't been formally approved for women in the U.S. yet. However, research supports it's efficacy, with a 2019 meta-analysis4 of 36 studies confirming that testosterone therapy significantly improves sexual function in postmenopausal women.

Contrary to her opinion on HRT for men, Comite prefers topical creams applied daily for women because it's a familiar routine for most women and easier to control than other methods.

"Pellets are not my favorite path because it's hard to control, and a lot of times the levels get too high," she says.

This aligns with the research. The 2019 analysis4 found that non-oral routes of testosterone administration, like transdermal creams, had a neutral effect on lipid profiles, while oral testosterone was associated with unfavorable changes in cholesterol.

Another option is DHEA, a chemical precursor to hormones that the body can convert into testosterone. But not everyone converts it efficiently. Comite recommends testing to see whether DHEA supplementation actually raises your testosterone levels before committing to it long-term.

Testosterone decline is inevitable, but how you respond to it isn't. The first step is getting tested, and you can get tested correctly following Comite's protocols.

Measure free testosterone (not just total) first thing in the morning after an overnight fast. Get at least two measurements to confirm your levels. And don't rely on lab "normal" ranges, those are population averages that don't reflect optimal health.