Maca does not increase testosterone. Multiple clinical trials measuring serum testosterone in men taking maca have found no statistically significant change compared to placebo. What maca does appear to do, however, is improve sexual desire, erectile function, and sperm quality through mechanisms that operate independently of testosterone levels. This distinction matters if you’re considering maca as a supplement.
What Clinical Trials Actually Show
The most direct evidence comes from a placebo-controlled trial in healthy adult men who took maca for 12 weeks. Researchers measured serum testosterone and estradiol throughout the study and found no difference between the maca group and the placebo group at any point. Despite this, the men taking maca reported a noticeable improvement in sexual desire starting around week eight.
A more recent trial focused specifically on men over 40 with symptoms of androgen deficiency, the group you’d most expect to benefit from a testosterone boost. After supplementing with gelatinized black maca, these men showed significant improvements on standardized questionnaires measuring erectile function, aging symptoms, and prostate health. Yet once again, neither total testosterone nor free testosterone changed between the maca and placebo groups.
One trial of yellow maca extract in infertile men actually found a 27% decrease in free testosterone after 16 weeks of use, though this finding hasn’t been widely replicated. The takeaway across all available human research is consistent: maca’s benefits don’t come from raising your testosterone.
How Maca Improves Sexual Function Without Testosterone
If maca isn’t changing hormone levels, how does it work? The honest answer is that researchers haven’t pinpointed one clear mechanism. The leading hypothesis involves the hypothalamus-pituitary-adrenal (HPA) axis, a communication loop between your brain and adrenal glands that regulates stress hormones and reproductive signaling. Maca’s unique combination of alkaloids, plant sterols, and glucosinolates appears to influence this system in a way that improves sexual function without directly altering circulating sex hormones.
In one clinical trial of postmenopausal women, maca reduced cortisol and ACTH (the hormone that triggers cortisol release) while also shifting other hormonal markers. This suggests maca may help by dialing down the body’s stress response, which can suppress libido and sexual function when chronically elevated. Rather than adding more testosterone to the picture, maca may be removing barriers that interfere with the hormones you already produce.
A systematic review of all available maca trials for sexual function concluded there is limited but consistent evidence that maca improves sexual desire. The researchers noted the effect appeared genuine but called for larger studies to confirm it.
Maca’s Effect on Sperm Quality
Where maca shows some of its most concrete results is in male fertility. In a trial of nine men taking 1,500 to 3,000 mg of maca daily for four months, researchers found increases in semen volume, total sperm count, the number of motile sperm, and overall sperm motility. Importantly, levels of testosterone, estradiol, and reproductive hormones like LH and FSH stayed unchanged throughout. Whatever maca does to sperm production, it bypasses the hormonal pathways you’d normally associate with fertility.
A pilot study of 20 healthy men using yellow maca for 12 weeks found sperm count increased by 20%, sperm concentration by 14%, motility by 14%, semen volume by 9%, and sperm shape quality by 21%, all with no measurable impact on hormone levels. These are meaningful improvements for men dealing with borderline fertility numbers.
Different Colors, Different Strengths
Maca comes in three main varieties: black, yellow, and red. They aren’t interchangeable. Black maca has the strongest research support for male fertility and sperm production. In animal studies comparing all three, black maca consistently outperformed the others for spermatogenesis. Yellow maca also improved sperm count in both animal and human studies, though the effects were somewhat less pronounced.
Red maca stands apart. It shows the least benefit for sperm parameters but has the strongest evidence for prostate health, specifically reducing prostate enlargement in animal models. If your goal is fertility support, black or yellow maca is the better choice. If prostate health is your concern, red maca has the most relevant research behind it.
Dosage Used in Studies
Across the clinical trials that showed positive results, daily doses ranged from 1,500 mg to 3,500 mg of maca root powder or gelatinized maca. Most studies used the 1,500 to 3,000 mg range. Trial durations varied from 6 to 16 weeks, with improvements in sexual desire typically appearing around 8 weeks and sperm quality changes requiring 12 to 16 weeks to manifest.
Gelatinized maca (which has been pre-cooked to remove starch) was the most common form used in successful trials. Raw maca powder was used less frequently. The distinction matters because gelatinization may improve digestibility and concentration of active compounds.
Safety Considerations
Maca has a long history of dietary use in Peru and is generally well tolerated in the dosage ranges studied. However, maca belongs to the cruciferous vegetable family, which means it contains glucosinolates, compounds that can interfere with thyroid function in large amounts. If you have a thyroid condition, this is worth discussing with your provider before adding maca to your routine.
Because maca appears to interact with the HPA axis and may influence cortisol, estrogen, and other hormonal signaling, people with hormone-sensitive conditions should approach it with caution. The fact that maca doesn’t raise testosterone doesn’t mean it’s hormonally inert. It clearly shifts something in the body’s regulatory systems, even if the exact mechanism remains under investigation.