Supplement analysis backed by scientific evidence · PT

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Limited evidenceMen's health

Maca Root

Popular for libido and "hormone balance", but every systematic review reaches the same verdict: a handful of small trials, largely from the same research groups, too weak to conclude anything. The pooled sperm-quality data are outright null.

What the science says

  • Sexual desire and function Limited evidence

    A systematic review found only 4 eligible RCTs. Two suggested improved sexual desire, in healthy men (1.5-3 g/day for 8-12 weeks) and in postmenopausal women; one in trained cyclists found nothing; one in men with erectile dysfunction showed a significant IIEF-5 improvement. Total sample sizes and methodological quality were too limited for firm conclusions.

  • Menopausal symptoms Limited evidence

    Four RCTs in perimenopausal and postmenopausal women all favoured maca on the Kupperman Menopausal Index or Greene Climacteric Score. But the trials were small, short and at unclear risk of bias, and the reviewers explicitly noted that efficacy and safety both remain unproven.

  • Semen quality Limited evidence

    A meta-analysis of 5 RCTs found no significant effect on sperm concentration versus placebo (weighted mean difference 2.22 million/mL, 95% CI -2.94 to 7.37, p = 0.4). Effects on motility and other parameters were mixed and inconsistent across trials in both infertile and healthy men.

Dosage & safety

Studied doseHuman trials used 1.5-3.5 g/day of dried maca root powder (gelatinized or raw) or an equivalent extract, for 6-12 weeks. Most sexual-function studies used 1.5-3 g/day; menopause studies 2-3.5 g/day. Gelatinized maca is easier to digest but has no proven efficacy advantage.
SafetyWell tolerated in short trials, with bloating and GI discomfort the main complaints. Raw maca contains glucosinolates that are goitrogenic in theory, which matters mainly with iodine deficiency or pre-existing thyroid disease. Long-term safety has not been established and systematic reviewers have specifically flagged that safety data are inadequate. Because effects on sex hormones are unclear, avoid in hormone-sensitive cancers and in pregnancy or breastfeeding without medical advice. Product identity is a genuine problem: authentication studies have found supplements containing little or no true Lepidium meyenii.

Scientific references

Where to buy

California Gold Nutrition, Superfoods, Certified Organic Peruvian Maca Root Powder, 8.5 oz (240 g)

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