Male vitality supplements: what the evidence supports

Two published findings frame everything else on this page, and neither appears in the marketing anywhere.

The first is about amounts. A 2023 analysis took the dietary supplements marketed for erectile health in one country, identified the ingredients with published evidence behind them, established a minimum effective daily amount for each, and scored every product against both. Two of the twenty-five products matched the higher-efficacy cluster. Three matched the lower one. Twenty — 80% — matched the criterion the authors called no expected efficacy. The ingredients were usually real; the amounts were usually negligible.

The second is about honesty. A 2025 study measured twenty products sold as natural sexual enhancers using high-performance liquid chromatography and found sildenafil or tadalafil — prescription drugs, undeclared — in seven of them.

Neither finding means the aisle is worthless. Both mean a reader has to look at the label rather than at the promise, and they are the reason this guide is organised by ingredient and by amount.

Lepidium meyenii is a root vegetable grown above 4,000 metres in the Peruvian Andes, where it is eaten as food. It is the only common ingredient on this shelf with two randomised, double-blind, placebo-controlled human trials behind it.

The first ran twelve weeks in men aged 21 to 56, comparing 1,500 mg and 3,000 mg a day of gelatinised maca against placebo. Self-reported sexual desire improved in the maca arms from week eight. The authors also measured serum testosterone and oestradiol and found no difference from placebo, and they built that finding into the paper's title: the effect had an absent relationship with testosterone. A logistic regression ruled out mood as the explanation as well.

That is worth holding onto, because almost the whole category is sold on a testosterone story. The single best trial in it measured testosterone and found nothing.

The second trial compared 1.5 g against 3.0 g a day in adults with medication-related sexual difficulty. The 3.0 g arm improved on both questionnaires; the 1.5 g arm did not. A dose-response relationship in a small trial is not proof, but it is the kind of detail that makes a reader ask what a product actually contains.

Outside sexual function, a 2024 systematic review and meta-analysis of maca and physical performance found large effect sizes across animal and human studies, with more effect at higher amounts.

Arginine is the amino acid the body converts into nitric oxide, the signal that relaxes smooth muscle in a vessel wall. It is the only ingredient on this shelf with a direct, uncontroversial mechanical link to what the aisle is sold for.

For blood pressure, a dose-response meta-analysis of 22 randomised trials found systolic pressure fell 6.40 mmHg and diastolic 2.64 mmHg on average, in people with and without raised pressure, with no further benefit above 9 g a day. A 2026 reassessment using 24-hour ambulatory monitoring in five trials found 24-hour systolic pressure down 4.23 mmHg.

For erectile function, a network meta-analysis of 15 randomised trials in 1,000 men ranked the options. Two carnitines with sildenafil came first at 97%, L-arginine with tadalafil second at 84%, sildenafil alone third at 79%, tadalafil alone fourth at 72%, and L-arginine alone fifth at 52%. No other regimen reached statistical significance. A separate meta-analysis of three trials in 184 men found arginine with pine-bark extract improved several questionnaire domains and made no difference to testosterone.

Every one of those trials worked in grams. That is the number to carry into any label comparison, and it is the number most labels in this aisle cannot meet because a capsule or a gummy has a physical ceiling.

Both are Brazilian barks, both are genuinely traditional, and both are where this aisle's evidence thins out.

Catuaba. A 2024 review of 74 native Brazilian plants used for male sexual dysfunction found fourteen with any experimental work behind the tradition, and Trichilia catigua is one of them. The work is ethnomedicinal and preclinical. A 2018 study of the bark's aqueous extract identified 26 compounds, found phenylpropanoid-substituted flavan-3-ols made up about 81% of the measured mass, and showed inhibition of monoamine oxidase A and acetylcholinesterase at around 121 micrograms per millilitre in vitro.

Muira puama. The published chemistry is solid: fourteen compounds isolated from Ptychopetalum olacoides bark, with two alkaloids — magnoflorine and menisperine — accounting for about 76% of what could be measured. Human evidence for the plant alone is essentially absent. A 2020 review of fifteen herbal sexual enhancers covers it for adverse effects rather than for efficacy, concluding that most were safe at therapeutic amounts and that drug interactions were the more serious concern.

A concentration in a dish is not an amount in a person, and traditional use is a reason to run a trial rather than a result. Neither statement is an attack on either plant; both are a description of where the evidence currently stands.