Sleep is the most underrated lever

In a controlled study, healthy young men limited to five hours of sleep a night for one week saw their daytime testosterone drop 10 to 15 percent.2 Normal aging lowers it about 1 to 2 percent a year. One short week of poor sleep did more than years of aging. Seven to nine hours of consistent sleep comes before anything else on this page.

Body fat works against testosterone two ways

Obesity is the condition most strongly tied to low testosterone in men.3 With modest extra weight, the main effect is lower SHBG, the protein that carries testosterone in the blood. With more significant obesity, inflammation and the conversion of testosterone to estrogen in fat tissue suppress the signal from the brain to the testes.3 Resistance training plus fat loss works on both.

Blood sugar and insulin

Insulin resistance lowers SHBG in men, the same mechanism that raises free androgens in women with PCOS. Steady meals with enough protein and fiber and regular training help, and fasting insulin belongs in the workup alongside glucose and A1c, because it rises years before glucose does.

Chronic stress

The stress system and the reproductive system share upstream signals, and chronic stress suppresses testosterone directly. Among supplements, ashwagandha has the best evidence here: a 2026 meta-analysis of 23 randomized trials found it lowered cortisol and raised testosterone in men, with no similar testosterone effect in women.4

What about vitamin D and zinc?

Vitamin D is sold hard as a testosterone booster. The most rigorous recent meta-analysis of randomized trials found no clear effect of vitamin D supplements on total testosterone in adult men.5 Correct a real deficiency for your bones and immune system, but do not expect it to move testosterone. For minerals, a 2025 study of young men linked zinc, iron and sulfur with more favorable testosterone levels.6 That is an association, not proof that a zinc pill will raise yours, so test before you supplement.

Get the testing right

  • Repeat morning blood tests. One low reading is not a diagnosis.
  • Total and free testosterone with SHBG, so you know how much is actually available.
  • A full thyroid panel, since thyroid problems can look like a hormone problem.
  • Fasting glucose, A1c and fasting insulin.

On testosterone therapy. If you take testosterone replacement or your doctor has raised it, nothing here is a reason to start, stop or change it yourself. Confirmed low testosterone with real symptoms deserves a proper workup with your physician, and whether therapy fits your case is their call to make with you.

See a doctor promptly for a new lump or mass in a testicle, or milky discharge from a nipple, which can point to a pituitary problem.

Common questions

What lowers testosterone in young men?

The biggest modifiable drivers are short sleep, excess body fat, insulin resistance and chronic stress. Each one can be measured and changed.

Can poor sleep lower testosterone?

Yes. In a controlled study, one week of five-hour nights dropped daytime testosterone 10 to 15 percent in healthy young men.

Does vitamin D raise testosterone?

The best recent meta-analysis of randomized trials found no clear effect in adult men. Correct a deficiency for other reasons, not to raise testosterone.