The most effective ways to increase male fertility involve managing heat exposure, improving your diet, exercising at the right intensity, sleeping enough, and reducing contact with hormone-disrupting chemicals. Because sperm take roughly 42 to 76 days to fully develop and mature, most changes need at least two to three months before they show up in a semen analysis.
Keep Your Testicles Cool
Testicles sit outside the body for a reason: they need to stay around 35°C (95°F), about two degrees below core body temperature. Even a small increase in scrotal temperature can suppress sperm production. Studies comparing fertile and infertile men found that infertile men had scrotal temperatures just 0.4 to 0.5°C higher than fertile men, on average. That’s a remarkably thin margin.
Several common habits push temperatures into that danger zone. Sitting with your thighs pressed together for an hour raises scrotal temperature by about 2.1°C. Using a laptop on your lap adds another 0.5 to 0.6°C on top of that. Tight underwear contributes an extra 0.5 to 0.8°C depending on the style and your posture. Hot tubs and saunas are worse: one study found that roughly two and a half hours of sauna exposure every two weeks cut sperm counts by up to 50 percent.
The encouraging news is that heat damage reverses. In a study of eleven men who regularly used hot tubs or hot baths for at least 30 minutes a week, five of them saw their motile sperm counts jump by an average of 491 percent within three months of stopping. After heat exposure ends, sperm counts typically hit their lowest point around four to five weeks later, then recover over the following ten to twelve weeks. Practical steps: switch to loose-fitting boxers, avoid placing laptops directly on your lap, limit hot tub sessions, and take breaks from prolonged sitting.
Follow a Mediterranean-Style Diet
A 2025 meta-analysis pooling data from over 1,800 men found that higher adherence to a Mediterranean diet was associated with meaningful improvements across every major sperm parameter. Sperm count increased by about 24 million sperm, total motility improved by nearly 9 percentage points, progressive motility by about 7.5 percentage points, and normal morphology by roughly 1 percent. That dietary pattern centers on vegetables, fruits, whole grains, legumes, nuts, fish, and olive oil, with limited red meat and processed food.
What you eat also determines your exposure to certain chemicals that harm fertility. Fruits and vegetables are the primary dietary source of pesticide residues for most people. That doesn’t mean you should avoid produce; it means washing it thoroughly and choosing organic options for the items you eat most frequently can reduce one source of endocrine disruption without sacrificing the dietary benefits.
Supplements That Have Evidence Behind Them
L-carnitine has the strongest clinical track record among fertility supplements for men. Doses between 1 and 3 grams per day for three to six months have been shown to improve sperm motility, concentration, and the percentage of normally shaped sperm. It also appears to lower levels of reactive oxygen species, which are unstable molecules that damage sperm cells. In head-to-head comparisons, L-carnitine outperformed CoQ10 combined with vitamin E for improving sperm concentration.
CoQ10 has more modest evidence. It supports sperm motility and can reduce oxidative damage, but the improvements tend to be narrower than what L-carnitine delivers. Zinc and selenium are commonly included in multi-ingredient fertility formulas, though isolated evidence for zinc alone is limited.
Antioxidant supplements in general seem most useful for men who already have elevated sperm DNA damage. A randomized, placebo-controlled trial of 263 men with unexplained infertility found that antioxidant supplementation significantly reduced DNA fragmentation, but only in men whose baseline fragmentation rate was 20 percent or higher. Men who started below that threshold didn’t see a meaningful benefit beyond what the placebo group experienced. If your DNA fragmentation is low to begin with, loading up on antioxidants probably won’t move the needle.
Exercise Enough, but Not Too Much
Moderate exercise improves sperm quality. The sweet spot appears to be working out at roughly 55 to 70 percent of your maximum capacity for 20 to 60 minutes, several days a week. That translates to brisk walking, easy jogging, swimming at a comfortable pace, or moderate resistance training.
Pushing past that threshold can backfire. Training at 80 to 90 percent of maximum capacity shifts hormone levels in ways that stress the reproductive system, raising cortisol and altering the signals that drive sperm production. Research has found that exceeding five hours per week of vigorous exercise is linked to reduced sperm concentration. Competitive cyclists are a well-studied example: during competition periods, their sperm motility dropped significantly compared to both recreational athletes and their own off-season values. The combination of intense effort, prolonged saddle pressure, and heat likely compounds the problem.
If you’re currently sedentary, starting a moderate exercise routine is one of the highest-impact changes you can make. If you’re already training hard, scaling back intensity or volume for a few months may help more than adding supplements.
Protect Your Sleep
Testosterone production is tightly linked to sleep. Most of the day’s testosterone is released during sleep cycles, and chronically short nights suppress the hormonal environment that sperm production depends on. The recommended range is 7 to 9 hours per night. Sleeping fewer than 7 hours consistently is associated with lower testosterone and poorer semen quality. Sleeping more than 9 hours has also been linked to negative reproductive effects, so the relationship follows a U-shaped curve where both extremes cause problems.
An estimated 50 to 70 million Americans have a chronic sleep disorder. If you fall into that group, addressing sleep may be the single most overlooked step you can take for fertility.
Reduce Exposure to Endocrine Disruptors
Certain synthetic chemicals interfere with male hormones and can damage sperm at the DNA level. The most common culprits are plasticizers found in food packaging and plastic containers, preservatives used in personal care products like soaps and lotions, and pesticides. These chemicals disrupt fertility through several pathways: they can mimic estrogen, block testosterone signaling, increase oxidative stress in the testes, and alter the DNA packaging inside sperm cells.
You absorb these compounds through your diet, your skin, and the air you breathe. Practical ways to limit exposure include avoiding heating food in plastic containers, choosing fragrance-free personal care products, switching to glass or stainless steel for food storage, and filtering your drinking water. None of these steps eliminates exposure entirely, but they reduce the daily load your body has to process.
How Long Changes Take to Work
Sperm production from start to finish takes roughly 42 to 76 days, with most estimates centering around 74 days. That means any change you make today, whether it’s dietary, supplemental, or behavioral, won’t fully show up in your semen for about two to three months. This is why most clinical trials of fertility supplements run for at least three months before measuring outcomes.
If you and your partner have been trying to conceive for 12 months without success (or 6 months if your partner is over 35), a formal evaluation is worthwhile. Current clinical guidelines recommend that the male partner be evaluated whenever there have been failed assisted reproduction cycles or recurrent pregnancy losses. The evaluation typically starts with a semen analysis and a physical exam, which can identify treatable causes that lifestyle changes alone won’t fix, such as varicoceles or hormonal imbalances.