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Limited evidenceMen's health

Fadogia Agrestis

A West African shrub that became a testosterone-booster trend on the strength of a single 2005 rat study — with zero human trials of any kind. A follow-up from the same laboratory found the same extract damaged rat liver and kidney at the doses that raised testosterone, which makes this one of the harder supplements on the market to justify.

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What the science says

  • Raises testosterone Limited evidence

    The entire claim traces to one rodent experiment in which an aqueous stem extract at 18-100 mg/kg for five days raised serum testosterone in male rats several-fold and increased mounting behaviour. No human being has ever had testosterone measured in a controlled trial of Fadogia agrestis, so neither an effective dose nor whether any effect occurs in men is known.

  • Improves libido and erectile function Limited evidence

    Aphrodisiac effects have been reported in rats, including a paroxetine-induced erectile dysfunction model where the extract restored several testicular and penile biomarkers. Rodent mounting frequency is a weak proxy for human sexual function, and no clinical trial in men exists at any dose or duration.

  • Product quality is reliable Limited evidence

    Analytical work using UHPLC-MS on commercial Fadogia supplements found substantial variability in phenolic content between products, and the plant is easily confused with related Vangueria species in trade material. Supplements are typically labelled only as a "10:1 extract" with no marker compound standardised, so what is in the capsule is essentially unverifiable by the buyer.

Dosage & safety

Studied doseThere is no evidence-based human dose. Labels commonly specify 300-600 mg/day of a 10:1 stem extract, a figure with no trial basis. The rodent doses that raised testosterone (18-100 mg/kg) would scale to roughly 200-1100 mg/kg-equivalent in humans depending on the allometric assumption — but the same range is where organ toxicity appeared in rats, so scaling it up is exactly the wrong lesson to draw.
SafetyThis is the entry's main point. In a 28-day rat study from the same group that reported the testosterone effect, the aqueous stem extract at 18-100 mg/kg produced dose-dependent liver and kidney damage: elevated serum ALT, AST and ALP, altered organ weights, and evidence of membrane and cellular injury. No human toxicology, no chronic-use data, and no drug-interaction data exist. Fadogia agrestis has no history of authorised food use in the EU or UK and is not an approved novel food there; it is sold in the US as a dietary supplement without pre-market safety review. Anyone with existing liver or kidney disease, on hepatotoxic medication, or drinking regularly has a clear reason to avoid it. If a man's goal is higher testosterone, the tested routes are weight loss, sleep, treating hypogonadism medically, or a prescribed therapy — not an untested herb with published rodent hepatotoxicity. Anyone using it anyway should have liver enzymes checked.

How to take it

TimingTiming does not matter - no dosing schedule has been studied in humans.
With food?With food, which is the only tolerability advice available for a herb with no human data.
Worth knowingGet baseline ALT, AST and ALP before starting and repeat them after a few weeks; published rodent hepatotoxicity is the reason this entry exists.

Interactions

With medications

  • medications that stress the liver, such as methotrexate, isotretinoin, or regular high-dose acetaminophen

    No human interaction data exist, but the same rat study that reported a testosterone effect also found dose-dependent liver and kidney injury, so combining it with a hepatotoxic drug stacks two risks. do not combine; if you take it anyway, have liver enzymes checked before and during use

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does Fadogia agrestis raise testosterone?

Nobody knows in humans: the claim traces to a single 2005 rat study, and no human trial of Fadogia agrestis has ever measured testosterone. The evidence grade is limited.

Is Fadogia agrestis safe?

Fadogia agrestis has no human safety data, and a 28-day rat study from the same lab that reported the testosterone effect found dose-dependent liver and kidney damage at the same doses. Avoid it if you have liver or kidney disease, take hepatotoxic medication or drink regularly, and have liver enzymes checked if you use it anyway.

How much Fadogia agrestis should I take?

There is no evidence-based human dose of Fadogia agrestis; the common 300-600 mg/day label figure has no trial basis. Scaling up the rat doses is the wrong lesson, because those doses also caused organ toxicity.

Does Fadogia agrestis improve libido?

Only in rats. Aphrodisiac effects of Fadogia agrestis have been reported in rodent studies, but no clinical trial in men exists at any dose, so the evidence is limited.

Scientific references

Where to buy

Nutricost, Fadogia Agrestis, 600 mg, 240 Capsules

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