What it is
Maca is a crucifer grown in the Peruvian Andes, whose dried and cooked hypocotyl is eaten: local populations advise against the fresh root. It comes in yellow, red and black ecotypes. People buy it for sexual desire, energy and, wrongly, to raise testosterone.
What the label does not say
- Testosterone does not move. In the 2002 trial of 57 men (1.5 or 3 g per day, 12 weeks), sexual desire increased at 8 and 12 weeks with no change in serum testosterone. Examine sums up that the effect does not go through testosterone, estradiol or LH.
- The effect on libido comes from four trials totalling 131 participants (2010 systematic review): two positive on desire, one positive on mild erectile dysfunction at 2.4 g per day, one negative in cyclists. The authors speak of limited data and trials too small to conclude.
- None of the four trials assessed adverse effects. The Health Canada monograph requires advice beyond 3 months of use (0.6 to 3 g per day) or 6 weeks (above 3 g).
- The claims in the Canadian monograph cover the emotional aspects of sexual health (3 to 3.5 g per day) and mood at menopause (2 to 3.5 g), not testosterone or performance.
The forms on the shelf
- So-called raw dried root powder: the least processed form; Andean tradition boils it.
- Gelatinized maca: heated under pressure to remove the starch, which improves digestibility and reduces digestive irritation according to a 2024 review; one trial nonetheless reported mild digestive upset with about 5 g per day for 30 days.
- Dry or hydroalcoholic extracts: the Health Canada monograph accepts them non-standardized; the 2024 review notes that a hydroalcoholic extract may contain compounds you do not ingest when eating the root.
- Black, red, yellow maca: the chemical profiles differ by colour and region, but the claims specific to each colour remain poorly supported.
Published reference values
- Trial doses: 1.5 to 3 g of powder per day. Canadian monograph: 2 to 3.5 g of dried hypocotyl depending on the claim, at most 3 g for the antioxidant claim.
- Reported effects: digestive upset, headaches, irritability, rare and transient; two isolated cases (vaginal bleeding, manic episode) according to the 2024 review.
- Health Canada asks for advice in case of a blood pressure problem, use of anticoagulants, anxiety or depression for products at 0.6 g and more per day.
When
With food according to Examine. The positive trials lasted 8 to 12 weeks; there are no data for prolonged use, hence Health Canada's duration limits.
To mention to a professional
- Blood pressure problem, anticoagulants, anxiety or depressive disorder, pregnancy and breastfeeding: check with a health care professional.
What it is sold for, and what the data show
Maca is sold to raise testosterone and energy. The trials show no effect on testosterone; on libido, a modest effect in four small trials; on energy, nothing solid. The risk seems low, the promise outruns the data.
From the plate first
In Peru, maca is a food: the 2024 review reports traditional consumption exceeding 100 g per day of cooked root. Elsewhere, it exists only as a supplement or a culinary powder.
Sources
- Health Canada, natural health product monograph, Maca (Lepidium meyenii)
- Shin et al., Maca (L. meyenii) for improving sexual function: a systematic review, BMC Complementary and Alternative Medicine, 2010
- Ulloa del Carpio et al., Exploring the chemical and pharmacological variability of Lepidium meyenii: a comprehensive review of the effects of maca, Frontiers in Pharmacology, 2024
- Examine.com, Maca
Educational information, drawn from the sources above. It does not replace the advice of a health professional, who remains the reference for your situation, your medications, pregnancy or breastfeeding.