Maca Root and Libido: The Best-Studied Botanical for Desire, and the Dose Problem

Of all the botanicals in men's supplements, maca has the cleanest evidence for the thing most men actually want: wanting more. It's not a testosterone booster, not a blood-flow agent, and doesn't pretend to be. It's a root vegetable with a small but real body of placebo-controlled research on sexual desire. The catch, as with most food-derived supplements, is that effective amounts are large.

What maca is

Lepidium meyenii grows at 13,000 feet in the Peruvian Andes, where it's been cultivated as a food for at least 2,000 years. It's a brassica, related to radish, turnip, and watercress. The dried root is milled into a nutty-tasting powder eaten in porridge and drinks. Its distinctive compounds include macamides, macaenes, and glucosinolates; which of them drives the libido effect is still unclear.

The evidence for sexual desire

Independent evidence The most-cited trial is a 12-week, double-blind, placebo-controlled study in 57 men aged 21–56, randomized to 1.5 g/day, 3 g/day, or placebo. Both maca groups reported increased sexual desire from week 8 onward; placebo did not. Crucially, serum testosterone and estradiol didn't change, and the effect wasn't explained by improvements in mood or anxiety.

A 2010 systematic review identified four RCTs; two in healthy men showed improved desire, one in men with ED showed improved function scores, and one in postmenopausal women showed improved sexual dysfunction scores. The reviewers concluded the evidence was positive but limited by small trial sizes.

A 2009 trial in men with mild ED found 2.4 g/day for 12 weeks improved erectile function scores and sexual well-being more than placebo. And a small trial found maca reduced SSRI-induced sexual dysfunction, particularly at 3 g/day.

Why hormone-independence is interesting

Editorial Most "libido" ingredients are really testosterone ingredients: raise T, hope desire follows. Maca appears to work through a different route, possibly via the nervous system, and shows effects even in men with normal testosterone. That makes it complementary to hormonal ingredients like Tongkat Ali rather than redundant. In the Spartamax formula, maca is the piece aimed at desire directly. See causes of low libido in men for why desire and hormones don't always track.

Black, red, or yellow?

Maca comes in several phenotypes. Yellow is most common and most studied for libido. Black maca has been studied for sperm parameters and memory in animals; red for prostate size in rats. In humans, the libido evidence is mainly from mixed or yellow maca. Spartamax doesn't specify.

Dose and format

The studied doses are 1.5–3 g/day of dried powder, sometimes gelatinized (pre-cooked to remove starch and improve digestibility). Concentrated extracts (4:1, 10:1) exist and could theoretically deliver an equivalent dose in a smaller amount, but they're less studied and standardization is inconsistent.

Editorial A Spartamax gummy weighs about as much as a single clinical dose of maca powder. Seven ingredients share the gummy. Unless the formula uses a highly concentrated extract, which the vendor doesn't state, the maca content is a small fraction of the amounts studied. Of all seven ingredients, this is where the gap between research and gummy capacity is widest. The dosage page discusses whether adding a separate maca product makes sense.

Safety

Maca is a food, and its safety record reflects that. Trials report no significant adverse effects at 3 g/day. Two cautions: raw (non-gelatinized) maca contains glucosinolates that could theoretically affect thyroid function in people with iodine deficiency, and some users report mild jitteriness or GI upset. People with hormone-sensitive conditions are sometimes advised to be cautious, though maca doesn't appear to alter hormone levels.

Related: the ingredients page covers all seven compounds, and the how it works page explains where maca fits in the formula's logic.