Maca root for men and women: what's known about libido, menopause, hormones and safety

What maca root is

Maca (Lepidium meyenii) belongs to the cabbage and mustard family. It’s grown high in the Peruvian Andes, and its rounded root is the part people eat. In Peru it’s boiled, baked, made into porridge or fermented into a drink.

From the late 1990s, maca was marketed worldwide as “Peruvian ginseng” for libido and fertility, and it’s now also grown on a large scale in China. A 2018 review from the UCL School of Pharmacy concluded that the reproductive health claims for maca can’t yet be fully supported by science. Its authors also warn that the lack of rules on how maca is produced and marketed threatens consumer safety.

On iHerb, maca comes in several forms:

• raw powder – the dried, ground root;
• gelatinised powder – processed maca, the type used in the main trial in men;
• capsules – powder or extract, easier to dose;
• different colours – yellow, red and black maca; differences between them have barely been studied.

Maca for men: libido, erections and testosterone

The best-known trial in men was run in Peru. Men aged 21–56 took 1,500 or 3,000 mg of gelatinised maca or a placebo for 12 weeks.

• Sex drive improved on maca from week 8.
• Testosterone and oestradiol in the blood were no different from placebo.
• Mood and anxiety didn’t explain the effect; the researchers checked separately.

A 2010 systematic review found 4 randomised trials on sexual function. Two showed a benefit (in healthy men and in menopausal women), and one in cyclists found no effect. Another, in men with erectile dysfunction, found improvement on a questionnaire. The reviewers’ verdict: limited evidence, with too few trials and participants.

Results for sperm quality and fertility are mixed. If you’re struggling to conceive, see your GP rather than relying on maca. Other options are covered in our guide to supplements for men.

Maca for women: menopause and libido

For menopause, maca has been tested in 4 small randomised trials. All found improvements on standard symptom scales. But the 2011 review judged the number of trials, participants and their quality too limited for firm conclusions, and noted that safety hasn’t been proven.

Maca has also been tested in women whose antidepressants (SSRIs or SNRIs) had lowered their sex drive. 45 women took 3 g of maca a day or a placebo for 12 weeks. Sexual function recovered more often on maca, especially in postmenopausal women, and it was well tolerated.

For more on menopause and women’s health, see our guide to supplements for women.

Maca and hormones: why it isn’t HRT

Maca is often called a “natural hormone balancer”. The evidence doesn’t back this up:

• in men, maca didn’t change LH, FSH, prolactin, testosterone or oestradiol;
• in women, some trials saw changes in certain hormones and others didn’t; where postmenopausal women had better sexual function, LH tended to rise and FSH to fall;
• in lab studies, maca extracts showed oestrogen-like activity, but what this means for people is unknown.

There’s a practical point too. In one reported case, a woman taking a teaspoon of maca powder a day had raised testosterone on a blood test and bleeding between periods. Maca may interfere with testosterone tests, so mention it if you’re having hormone tests.

Maca doesn’t replace HRT or treatment for infertility or erectile dysfunction. For hot flushes, period changes or erection problems, start with your GP.

Maca and your thyroid

Maca is related to cabbage and contains glucosinolates. Substances of this type in cabbage, broccoli and other cruciferous vegetables are classed as goitrogens: they can interfere with how the thyroid uses iodine. According to the Linus Pauling Institute, this only matters clinically in large amounts or when iodine intake is low.

Human data are scarce. In a small 2015 trial, 29 postmenopausal women in Hong Kong took 3.3 g of maca a day for 6 weeks. Their TSH, the main thyroid blood test, didn’t differ from placebo. Nobody has studied longer use or people with thyroid disease. Sensible precautions:

• if you have a thyroid condition, ask your GP before taking maca;
• make sure you get enough iodine – see our guide to selenium and iodine;
• stay within the doses used in trials, up to about 3 g a day.

How to take maca

There’s no official dose. Most trials used 1.5–3.5 g a day for 6–12 weeks.

1. Start at the lower end, for example 1.5 g a day, and see how you get on.
2. Give it 8–12 weeks; in the men’s trial, the effect on sex drive appeared from week 8.
3. Note your starting point: rate sex drive or hot flushes from 0 to 10.
4. If nothing has changed after 3 months, stop.

The same plan week by week, with what to check at each stage:

Maca side effects and who should avoid it

In trials, maca was well tolerated. Memorial Sloan Kettering lists occasional reports of menstrual changes, mood swings, cramps, gastritis and trouble sleeping.

Avoid maca, or check with your doctor first, if you have:

• pregnancy or breastfeeding – there’s no safety data;
• a hormone-sensitive cancer (breast, womb) – discuss it with your oncology team;
• a thyroid condition – because of the glucosinolates;
• blood pressure medicines such as losartan – maca boosted its effect in rats and lowered diastolic blood pressure in the Hong Kong trial; the combination hasn’t been tested in people;
• upcoming hormone tests – maca may distort the result.

If you take several supplements, check our compatibility chart. Similar promises are made for ashwagandha, which has its own risks.

How to choose maca on iHerb

1. Run through the checklist above and rule out the warnings.
2. Choose a form: capsules for a precise dose, powder if you add maca to food.
3. Check how much maca is in a serving and how many capsules make 1.5–3 g.
4. Prefer products with independent quality testing, as mass production makes the raw material harder to control.
5. Note an end date 8–12 weeks ahead.

For more in this section, see men’s health and sport. Not sure what you need? Try our vitamin check.