Fadogia agrestis is a shrub from tropical Africa in the coffee family (Rubiaceae). Botanists now also classify it as Vangueria agrestis. Traditional medicine has used it as a decoction for fever, pain and malaria, and as an aphrodisiac (Avula et al., Biomed Chromatogr 2020; Avula et al., Planta Med 2019). Its stem extract is now sold in dietary supplements aimed at testosterone and male sexual function.
The most important fact is how little evidence exists. Everything known about its hormonal effects comes from a small number of studies in male rats, almost all from one research group in Nigeria. We found no published human trial and no registered one. The same rat studies that reported higher testosterone also reported changes in testicular, liver and kidney markers that the authors interpreted as signs of toxicity.
This page summarizes what the animal studies and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Type | Herbal dietary supplement (stem extract) |
| Plant | Fadogia agrestis Schweinf. ex Hiern (also Vangueria agrestis), family Rubiaceae; native to tropical Africa |
| Route | Oral |
| Doses studied | 18, 50 and 100 mg/kg/day of aqueous stem extract, in rats only |
| Human trials | None found in PubMed or ClinicalTrials.gov (searched October 2026) |
| Half-life | Unknown; no pharmacokinetic data in animals or humans |
| Reported effect | Higher serum testosterone and mating behavior in male rats |
| US status | Sold as a dietary supplement; not FDA-approved for any use; not a controlled substance |
| WADA status | Not named on the 2026 Prohibited List |
What it is
Fadogia agrestis is a shrub, and the rat studies used a water extract of its stem. Chemists have identified many compound families in the plant, but none has been linked to an effect on hormones:
- monoterpene glycosides (Anero et al., Phytochemistry 2008);
- ursane-type triterpenoid glycosides, benzophenone glycosides and an iridoid glucoside from the roots (Osman et al., Nat Prod Res 2020);
- phenolic acids and flavonoids; one profiling study identified 73 compounds across the aerial parts and roots (Avula et al., 2020).
In the first rat study, a simple screen of the stem extract found alkaloids and saponins, with weaker signals for anthraquinones and flavonoids (Yakubu et al., Asian J Androl 2005). There is no standardized extract or agreed marker compound, unlike the eurycomanone used for tongkat ali.
How it works in the body
How Fadogia agrestis might affect testosterone is not known. The rat study authors proposed that the extract raises blood testosterone and that this explains the change in mating behavior, but did not identify an active compound or show how the rise occurs (Yakubu et al., 2005).
In a later rat model of erectile dysfunction, the extract raised nitric oxide and cGMP (the signaling molecules that relax penile blood vessels) and lowered PDE5, the enzyme that sildenafil blocks. The authors attributed this to antioxidant effects (Ogunro and Yakubu, Reprod Sci 2023).
No study has measured absorption, blood levels or half-life of any Fadogia agrestis compound, in animals or in people.
What the research shows
All studies below were in rats. They used small groups, a single extract made in the lab, and were run largely by the same research group. Their results should not be assumed to apply to people.
| Study | Design | Doses (oral, per kg body weight) | Main findings |
|---|---|---|---|
| Yakubu 2005 | Male rats, sexual behavior and serum testosterone at days 1, 3 and 5 | 18, 50, 100 mg/kg daily | More mounts and intromissions, shorter latencies, longer time to ejaculation; serum testosterone rose in all dose groups |
| Yakubu 2008 | Male rats, 28 days, then 10 days off | 18, 50, 100 mg/kg daily | Changes in testicular weight, cholesterol and enzymes judged adverse; partial recovery, mainly at 18 mg/kg |
| Yakubu 2009 | Male rats, 28 days, liver and kidney | 18, 50, 100 mg/kg daily | Enzyme shifts from organs to blood and higher lipid peroxidation; no deaths or visible organ changes |
| Ogunro 2023 | 30 male rats with erectile dysfunction induced by paroxetine; 5 per group | 18, 50, 100 mg/kg; sildenafil 50 mg/kg as comparator | Extract, like sildenafil, raised nitric oxide, cGMP and antioxidant enzymes and lowered PDE5 to levels near untreated rats |
Testosterone and sexual behavior
The 2005 study is the main basis for testosterone claims. All three doses increased mount and intromission frequency, shortened the time to the first mount and intromission, and prolonged ejaculatory latency. Serum testosterone rose in all treated groups “in a manner suggestive of dose-dependence” (Yakubu et al., 2005). The abstract does not report the size of the testosterone rise, and the study lasted only 5 days.
Erectile function model
In rats given the antidepressant paroxetine to induce erectile dysfunction, the extract at all three doses brought penile and testicular nitric oxide, cGMP, PDE5 and antioxidant measures back to levels similar to untreated rats. Sildenafil did the same. The authors recommended its use in erectile dysfunction only after clinical trials (Ogunro and Yakubu, 2023).
Human evidence
There is none. We found no human study of Fadogia agrestis in PubMed and no registered trial on ClinicalTrials.gov. No human dose has ever been tested, so supplement doses are not based on trial data.
About “testosterone booster” claims. Statements that Fadogia agrestis raises testosterone in men are extrapolated from a 5-day study in rats. Across marketed testosterone boosters in general, a 2024 systematic review of human trials found that most fail to raise total testosterone (Morgado et al., Int J Impot Res 2024).
Side effects and risks
No human safety data exist. The animal findings below are the only toxicity information available.
Testicular changes in rats
After 28 days at 18, 50 or 100 mg/kg, rats had a higher testis-to-body-weight ratio, higher testicular cholesterol, sialic acid and glycogen, and lower testicular protein and alkaline phosphatase and glutamate dehydrogenase activity. The authors concluded these were “indications of adverse effects” on testicular function. After 10 days off the extract, recovery occurred mainly at the lowest dose, which the authors described as the dose used in folk medicine (Yakubu et al., J Ethnopharmacol 2008). Sperm counts and fertility were not reported in the abstract.
Liver and kidney markers in rats
In the same 28-day dosing design, the extract lowered alkaline phosphatase, lactate dehydrogenase and gamma-glutamyl transferase inside the liver and kidney while raising them in the blood. Serum malondialdehyde, a marker of lipid peroxidation (oxidative damage to cell membranes), rose in all treated groups. No rats died, and organ weights and appearance were unchanged. The authors interpreted the pattern as damage to liver and kidney cell membranes (Yakubu et al., Hum Exp Toxicol 2009).
Toxic relatives in the same genus
Two other Fadogia species, F. homblei and F. monticola, cause gousiekte, a heart syndrome of ruminant livestock in southern Africa linked to the plant toxin pavettamine (Hurter et al., Onderstepoort J Vet Res 1972; Van Elst et al., Phytochemistry 2013). These studies did not examine F. agrestis, so whether this is relevant to it is unknown.
Who has no safety data
Because there are no human studies, nothing is known about its safety in:
- people with liver or kidney disease;
- men trying to conceive, given the testicular findings in rats;
- people taking prescription drugs, since no interaction studies exist;
- pregnant or breastfeeding women, and children.
Quality and contamination
Under US law, FDA does not have the authority to approve dietary supplements before they are marketed, and it does not review their labels or claims in advance (FDA).
Product content is variable. A University of Mississippi analysis of 17 dietary supplements labeled as containing Fadogia agrestis found its phenolic marker compounds in 12, at 0.3–2.7 mg per daily serving, and detected none in the other 5 (Avula et al., Planta Med 2019). The same group developed methods to tell the plant’s root, aerial parts and supplements apart (Avula et al., 2020).
Legal status
Fadogia agrestis is not named in the US controlled-substance schedules for anabolic steroids (21 CFR 1308.13), and it is not named on the WADA 2026 Prohibited List. Because supplement content is not verified before sale, athletes cannot rule out contamination of any product.
Key takeaways
- A rat-only evidence base. Testosterone and sexual-behavior effects come from short studies in male rats, mostly from one research group.
- No human trials at all. No human study or registered trial was found, so there are no human doses, effect sizes or safety data.
- The same rat studies raised safety signals. At 18–100 mg/kg/day for 28 days, rats showed testicular, liver and kidney marker changes that the authors judged adverse.
- No pharmacokinetic data. Absorption and half-life are unknown in any species.
- Product content varies. In one analysis, 5 of 17 supplements labeled as Fadogia agrestis had none of its marker compounds detected.
- Better-studied alternatives exist, though still modest. Tongkat ali and Tribulus terrestris have at least been tested in human trials.
Sources
- Yakubu MT, Akanji MA, Oladiji AT. Aphrodisiac potentials of the aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male albino rats. Asian J Androl. 2005;7(4):399–404. PubMed.
- Yakubu MT, Akanji MA, Oladiji AT. Effects of oral administration of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem on some testicular function indices of male rats. J Ethnopharmacol. 2008;115(2):288–292. PubMed.
- Yakubu MT, Oladiji AT, Akanji MA. Mode of cellular toxicity of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male rat liver and kidney. Hum Exp Toxicol. 2009;28(8):469–478. PubMed.
- Ogunro OB, Yakubu MT. Fadogia agrestis (Schweinf. Ex Hiern) stem extract restores selected biomolecules of erectile dysfunction in the testicular and penile tissues of paroxetine-treated Wistar rats. Reprod Sci. 2023;30(2):690–700. PubMed.
- Anero R, Díaz-Lanza A, Ollivier E, et al. Monoterpene glycosides isolated from Fadogia agrestis. Phytochemistry. 2008;69(3):805–811. PubMed.
- Osman AG, Ali Z, Fantoukh O, et al. Glycosides of ursane-type triterpenoid, benzophenone, and iridoid from Vangueria agrestis (Fadogia agrestis) and their anti-infective activities. Nat Prod Res. 2020;34(5):683–691. PubMed.
- Avula B, Bae JY, Wang YH, et al. Chemical profiling and characterization of phenolic acids, flavonoids, terpene glycosides from Vangueria agrestis using ultra-high-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry and metabolomics approach. Biomed Chromatogr. 2020;34(9):e4840. PubMed.
- Avula B, Bae JY, Raman V, et al. Quantification of phenolic compounds from Fadogia agrestis and dietary supplements using UHPLC-PDA-MS. Planta Med. 2019;85(2):145–153. PubMed.
- Hurter LR, Naudé TW, Adelaar TF, et al. Ingestion of the plant Fadogia monticola Robyns as an additional cause of gousiekte in ruminants. Onderstepoort J Vet Res. 1972;39(1):71–81. PubMed.
- Van Elst D, van Wyk B, Schultz A, Prinsen E. Production of toxic pavettamine and pavettamine conjugates in the gousiekte-causing Fadogia homblei plant and its relation to the bacterial endosymbiont. Phytochemistry. 2013;85:92–98. PubMed.
- Morgado A, Tsampoukas G, Sokolakis I, et al. Do “testosterone boosters” really increase serum total testosterone? A systematic review. Int J Impot Res. 2024;36(4):348–364. PubMed.
- ClinicalTrials.gov. Search results for “fadogia.” Accessed October 12, 2026. ClinicalTrials.gov.
- Food and Drug Administration. Questions and answers on dietary supplements. FDA.
- Drug Enforcement Administration. Schedules of controlled substances: Schedule III. 21 CFR 1308.13. eCFR.
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA 2026 Prohibited List.