Maca has one genuinely interesting finding in its favour and a lot of marketing built on top of it. The interesting part is that its apparent effect on desire seems to happen without touching hormones at all — which nobody has fully explained.
Lepidium meyenii is a cruciferous root vegetable — a relative of broccoli and radish — grown above 4,000 metres in the Peruvian Andes. It has been eaten there as a staple food for centuries, typically dried and boiled, in quantities far larger than any supplement provides.
That food history is genuinely reassuring on safety. It also sets up the central problem with maca supplements, which we will get to.
Several small randomised controlled trials have examined maca supplementation against self-reported sexual desire, and the results are reasonably consistent in showing improvement over placebo across durations of around eight to twelve weeks.
These are small studies and the outcome is subjective — self-reported desire is not a blood marker. But the placebo-controlled design matters, and the finding has appeared in more than one independent trial. The published literature is worth reading directly if you want the detail.
Here is the part that makes maca scientifically interesting. Trials that measured hormones alongside desire found no significant changes in testosterone, oestrogen or luteinising hormone — yet the reported effect on desire persisted.
Whatever maca is doing, it does not appear to be hormonal. Proposed explanations involve effects on neurotransmitter systems or on specific plant compounds called macamides, but none is established. This is an open question rather than a settled mechanism.
The practical implication: be sceptical of any product marketing maca as a testosterone booster. The research specifically found that it is not one.
Maca is widely marketed for stamina and physical energy. This rests mainly on its traditional use in the Andes, where it has a long reputation as a tonic for working at altitude.
Controlled human trials on physical performance are limited and mixed. There is not much here to support the confident energy claims that appear in supplement copy. Treat this as traditional use — which is not nothing, but is not clinical evidence either.
Trials generally use 1,500 to 3,000 mg of maca daily. Andean dietary consumption is higher still.
That is a substantial quantity, and it creates a real problem for multi-ingredient supplements. A gummy weighing three or four grams in total — including the pectin or gelatin base, sweeteners and flavouring — cannot hold three grams of maca alongside six other actives. The arithmetic does not work.
This does not mean blends containing maca are useless. It means the maca content is almost certainly well below the studied range, and you should discount its contribution accordingly. If maca specifically is what you want, a single-ingredient powder is the honest way to get a research-comparable dose.
Maca has an excellent safety profile, helped considerably by its history as a food. Reported side effects are mild and uncommon — occasional digestive upset, and some people find it stimulating enough to disturb sleep if taken late.
As a cruciferous vegetable it contains goitrogens, which in very large quantities can affect thyroid function in people who are iodine deficient. This is a minor consideration at supplement dosages but worth knowing if you have a thyroid condition.
Maca has a real, replicated finding on self-reported desire, an unexplained mechanism that makes it scientifically interesting, and an excellent safety record. Those are genuine points in its favour.
Against that: the energy and endurance claims are thinly supported, it is definitively not a testosterone booster despite frequent marketing to the contrary, and the dosages used in research are difficult to deliver in a multi-ingredient product. If maca is the reason you are considering a blend, buy maca instead.
Our full analysis covers the formula, the dosage disclosure problem and who should skip it.
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