— Ariela Basson/Fatherly; Stocksy

Testosterone isn’t just a sex hormone — for men in particular, it plays an essential role in systems throughout the body, from muscle maintenance to the production of blood cells. When testosterone levels get too low, as they do for up to a third of men over the age of 40, the deficiency can cause an array of health effects, including depression, fatigue, low libido, erectile dysfunction, and more. If you have low T, testosterone replacement therapy is an option, but it’s not a quick fix and comes with potential side effects.

Luckily, for many men, taking the pharmaceutical route to fix low testosterone isn’t necessary, says Himanshu Arora, Ph.D., a professor of urology at the University of Miami Miller School of Medicine. Increasing testosterone can be as simple as a supplement or a lifestyle tweak.

It’s worth noting that some men need testosterone therapy to get back to normal — for example, when low testosterone is caused by an injury to the testicles or damage from chemotherapy. No supplement or healthy habit is going to compensate for these conditions, Arora says. So if you have symptoms of low testosterone, it’s worth getting checked out to make sure you don’t have a condition that would require testosterone therapy.

But once you get the clear, these five natural, evidence-backed ways to boost testosterone can help you get back to a testosterone level that has you feeling healthy and energized.

1. Work Out Consistently

It’s common knowledge that testosterone boosts exercise performance. That’s why anabolic steroids are illegal in professional sports. But it also works the other way around. “Exercise, especially resistance training, stimulates muscle-building hormones, including testosterone,” Arora says.

A 2020 analysis that examined the results of 48 different studies found that after just one workout, testosterone increased by 0.91 nanomoles per liter (nmol/L). (In men, normal baseline levels of testosterone are between 10 and 35 nmol/L.) After one hour, their testosterone returned to baseline. However, other studies suggest that consistent workouts could have a lasting impact.

In another study published in the journal Heart and Circulatory Physiology, 80 older men with low testosterone participated in either an exercise program or received testosterone replacement therapy. (A quarter of the men received both interventions; a quarter did nothing.) Unsurprisingly, the men who received testosterone therapy saw the largest increases in testosterone. But the group that only exercised also saw gains: After 12 weeks, 29% had testosterone levels in the normal range.

Arora says resistance training seems to be more effective for raising testosterone levels than cardio, although one small study on nine men found no difference between the two. Another study, however, had 15 men do two sessions of exercise: a 45-minute run at moderate intensity and a HIIT workout consisting of 90-second intervals. The HIIT workout had more of an effect on testosterone than the steady run.

2. Watch Your Weight

Between 50% and 80% of men with obesity also have low testosterone. One reason for this is that fat cells actually convert testosterone into estrogen, Arora says. For people with higher body fat, losing some weight can help counter that effect.

A 2013 analysis that pooled the results of 24 different studies found that both low-calorie diets and bariatric surgery boosted testosterone levels in men with overweight or obesity. In five of the included studies, that difference was more than 10 nmol/L, and considering that the normal male testosterone range is between 10 and 35 nmol/L, that’s a huge change.

3. Consider Supplementing Zinc and Vitamin D

There’s solid evidence that vitamin D and zinc supplements can boost testosterone, Arora says. Both nutrients play an essential role in testosterone production.

Cells in the testes have vitamin D receptors, and “activating” those receptors might act like an on/off switch for testosterone production. Meanwhile, zinc attaches to the enzyme that produces testosterone, triggering it to do its thing. If you already have enough vitamin D and zinc, these supplements probably won’t do much — one study published in the journal Nature Medicine found that men who already got enough zinc in their diets didn’t see their testosterone increase after starting a supplement. But if you’re low on either of them, supplementing it may help.

A quick note on “natural” testosterone supplements: DHEA, androstenedione, and androstenediol. These health-aisle products contain naturally occurring chemicals that the body converts into testosterone. But an extra dose of these chemicals via supplements doesn’t appear to do much for testosterone production, Arora says. “The studies show inconsistent effects,” he says. “Some suggest it might actually increase estrogen and cause a hormonal imbalance.”

4. Prioritize Your Sleep

You’ve heard of circadian rhythm, probably in relation to sleep/wake cycles. But this system also governs the natural ebb and flow of hormones in the body throughout the day, including testosterone. Sleep is an essential part of regulating that cycle. “Disruptions,” says Arora, “lead to imbalance.”

Sleep scientists brought 10 healthy young men into a lab for 11 nights. Three of those nights involved a solid 10 hours of shut-eye; then, for eight nights, the men were only allowed five hours of sleep. By the end of the study, which was published in 2011 in JAMA, the men’s testosterone decreased, on average, by between 10% and 15%. This suggests that if you’re looking to increase your testosterone levels, consistently getting enough sleep — between seven and nine hours per night — is paramount.

5. Reduce Your Stress

When we’re stressed, the body goes into emergency mode, devoting resources only to systems necessary to survival. Cortisol, a hormone the body releases when stressed, acts as a shutoff switch to these systems — including the production of testosterone.

Following a two-week survival training, U.S. Navy soldiers saw their testosterone levels decline, on average, from normal to low levels, according to a study published in the journal Aerospace Medicine and Human Performance.

“If you’re looking to increase testosterone, stress reduction is crucial,” Arora says.