Maca root shows modest but consistent trends toward increasing semen volume, with one clinical trial in healthy men finding a 9% increase after 12 weeks of supplementation. The evidence is more encouraging for total sperm count and motility than for volume alone, but the overall picture suggests maca can positively influence several aspects of sperm health.
What the Clinical Trials Show
A double-blind, placebo-controlled pilot study gave healthy men maca root daily for 12 weeks and tracked their semen parameters throughout. The maca group saw semen volume rise by 9%, total sperm count increase by 20%, sperm concentration climb by 14%, and normal sperm shape improve by 21%. The placebo group also saw a 20% bump in total count, but their concentration stayed flat and both motility and normal shape actually declined by 10% and 14%, respectively. None of the improvements in the maca group reached statistical significance on their own, which is partly a limitation of the small sample size (11 men per group), but the consistent upward trend across every measured parameter is notable.
An earlier study by Gonzales and colleagues produced more dramatic numbers. Nine healthy men who took maca for 16 weeks saw sperm concentration increase by 35%, total sperm count jump by 84%, and motile sperm count more than double. A separate study of ten men diagnosed with infertility found more modest gains: motile sperm count rose by 10% and normal sperm shape improved by 12% after 12 weeks.
A 2022 systematic review and meta-analysis in Frontiers in Pharmacology pooled the available trials and found mixed results for motility and morphology. In men with infertility, one trial showed improved motility while another did not. For sperm shape, no major difference was seen between maca and placebo in the infertile group. Healthy men tended to show more consistent improvements. The takeaway: maca is not a guaranteed fix, but it repeatedly trends in the right direction across multiple sperm parameters including volume.
How Maca Works Without Changing Hormones
One of the most surprising findings about maca is that it improves sperm production without altering testosterone or other reproductive hormones. Multiple clinical trials have measured blood levels of testosterone, estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin in men taking maca. In every case, the levels stayed the same as in the placebo group. This holds true at both low and high doses.
This means maca is not working the way most people assume. It does not boost testosterone to stimulate sperm production. The exact mechanism remains unclear, but researchers believe maca’s bioactive compounds may act directly on the testes or at hormone receptors in reproductive tissue rather than raising circulating hormone levels. One proposed pathway involves a compound in maca that interacts with a specific liver enzyme, potentially preserving more of the body’s natural hormone precursors for testosterone production without changing measurable blood levels. This distinction matters because it means maca is unlikely to cause the hormonal side effects associated with testosterone-boosting supplements.
Black Maca Outperforms Other Varieties
Maca comes in several color varieties, and they are not interchangeable when it comes to sperm health. Animal research comparing black, yellow, and red maca found clear differences. Black maca was the only variety that increased daily sperm production, and it did so after both short-term (7-day) and long-term (42-day) treatment. Yellow and red maca had no effect on sperm production at either time point.
After 42 days, black maca also uniquely improved sperm motility, the ability of sperm to swim effectively. Red maca, interestingly, reduced prostate weight without affecting sperm parameters at all, suggesting it may have entirely different therapeutic applications. If your goal is specifically to improve sperm volume and count, black maca is the variety best supported by the research.
Dosage Used in Studies
Clinical trials in men have used maca at either 1.5 grams or 3.0 grams per day. For sexual function outcomes, the 3.0 gram dose consistently outperformed the 1.5 gram dose. In a dose-finding study, only the 3.0 gram group showed significant improvement in sexual function scores, while the 1.5 gram group did not separate from baseline.
For sperm-specific improvements, one notable finding is that increases in sperm count did not appear to be dose-dependent, meaning the lower dose produced similar changes to the higher dose. Still, most positive results in the literature come from studies using doses in the 1.5 to 3.0 gram range taken daily for at least 12 weeks. The 16-week study that showed the most dramatic sperm count improvements used a similar dosing window.
How Long Before You See Changes
Sperm take roughly 74 days to fully mature, so any supplement targeting sperm production needs time to work. The animal data on maca shows that some early cellular changes in the testes begin within the first week, particularly with black maca, which increased daily sperm production after just 7 days of treatment. But the full range of benefits, including improved motility, only appeared after 42 days of continuous use.
In human trials, 12 weeks (about 84 days) is the standard study length, and that aligns well with the biology of sperm development. The strongest results came from the 16-week study. If you are considering maca for sperm health, expect to take it consistently for at least three to four months before a semen analysis would reflect meaningful changes.
Safety Profile
Maca has a favorable safety record in clinical trials. It has been consumed as a food in the Peruvian Andes for centuries, and the doses used in research (1.5 to 3.0 grams daily) fall well within what is considered safe. Because maca does not alter levels of testosterone, estrogen, thyroid hormones, prolactin, or cholesterol markers like HDL and LDL, it avoids the hormonal disruption that comes with many male fertility supplements. Prostate-specific antigen (PSA), a marker of prostate health, also remained unchanged in studies. The most commonly reported side effects in trials are mild and gastrointestinal in nature.