Does Fadogia Agrestis Really Increase Testosterone?

Fadogia agrestis is often sold as a natural testosterone booster, but the research behind that claim is limited. The most frequently cited evidence comes from a 2005 experiment in male rats rather than a clinical trial in men.

That study measured serum testosterone and sexual behaviour after several days of treatment. A later study by the same researchers examined what happened to testicular function when rats received the extract for 28 days.

What Is Fadogia Agrestis?

Fadogia agrestis is a shrub in the Rubiaceae family that has traditionally been used in parts of Nigeria as an aphrodisiac and sexual invigorator. The researchers who conducted the 2005 study described the stems as the part commonly used for this purpose.

The preparation tested in the study was an aqueous stem extract. The dried stem was powdered, extracted in distilled water for 48 hours, filtered, concentrated, and then reconstituted before being given to the rats.

Chemical screening detected saponins and alkaloids, with smaller amounts of flavonoids and anthraquinones. Steroids and caffeine were not detected in the extract.

What Did the 2005 Study Test?

Yakubu, Akanji, and Oladiji divided male rats into groups receiving 18, 50, or 100 mg/kg of aqueous Fadogia agrestis stem extract. A control group received distilled water. Sexual behaviour and serum testosterone were assessed after one, three, and five daily doses.

The researchers were investigating the plant’s traditional use as an aphrodisiac. Testosterone was measured alongside behavioural indicators including mount frequency, intromission frequency, mount latency, intromission latency, and ejaculatory latency.

How Much Did Fadogia Agrestis Increase Testosterone in Rats?

By day 5, serum testosterone concentrations were approximately twice the control value in rats receiving 18 mg/kg, three times the control value at 50 mg/kg, and six times the control value at 100 mg/kg. The increases were statistically significant at all three doses.

The researchers described the pattern as suggestive of a dose-dependent response, with larger increases generally appearing at the higher doses.

Did Fadogia Agrestis Affect Sexual Behaviour?

Mount frequency and intromission frequency increased in rats receiving Fadogia agrestis, while the time before the first mount and first intromission decreased. Ejaculatory latency increased as well. All three doses produced statistically significant changes compared with controls.

At 100 mg/kg on day 5, both mount frequency and intromission frequency were about 3.7 times their respective control values.

The researchers interpreted these changes as evidence of aphrodisiac activity and proposed that the accompanying rise in testosterone could help explain the behavioural effects.

How Might Fadogia Agrestis Affect Testosterone?

The 2005 study did not establish the biochemical mechanism responsible for the testosterone increase.

The authors suggested that saponins in the extract might play a role by increasing luteinising hormone, which could in turn stimulate testosterone production. Luteinising hormone was not measured, however, so the proposed pathway was not directly tested.

The extract also contained alkaloids and small amounts of other phytochemicals. The researchers did not isolate individual compounds or determine which constituent was responsible for the hormonal effects.

What Happened When Rats Took Fadogia Agrestis for 28 Days?

A 2008 study by the same researchers gave male rats 18, 50, or 100 mg/kg of aqueous Fadogia agrestis stem extract every day for 28 days.

After treatment, the testes-to-body-weight ratio, testicular cholesterol, glycogen, and sialic acid increased, while testicular protein concentration decreased.

Alkaline phosphatase and glutamate dehydrogenase activity decreased, while acid phosphatase and gamma-glutamyl transferase activity increased.

The researchers interpreted these biochemical changes as evidence that the extract had altered testicular function and concluded that the effects could impair the functional capacity of the testes, particularly at 50 and 100 mg/kg.

The study did not directly measure infertility or reproductive success. Its conclusions were based on biochemical markers used to assess testicular function.

Did Testicular Function Return to Normal After Stopping Fadogia Agrestis?

After the 28-day treatment period, five rats from each group stopped receiving the extract and were observed for another 10 days.

Glycogen returned to control values across the treated groups, while several other measurements moved toward normal without fully recovering; recovery was clearest at 18 mg/kg. Alkaline phosphatase returned to the control range at 18 mg/kg, and gamma-glutamyl transferase returned to control values at 18 and 50 mg/kg.

The testes-to-body-weight ratio remained significantly above the control value at 18, 50, and 100 mg/kg after the 10-day recovery period, and glutamate dehydrogenase also remained below control values at all three doses. Neither marker recovered even at the lowest dose.

The authors described the overall pattern at 18 mg/kg as suggesting that the changes were not permanently toxic in the rats, although several individual measurements had not returned fully to control values by day 38.

Does Fadogia Agrestis Increase Testosterone in Humans?

Neither of these studies tested Fadogia agrestis in people.

The 2005 experiment shows that the aqueous stem extract used by the researchers increased serum testosterone in male rats. It cannot establish whether Fadogia agrestis raises testosterone in men, how large any effect might be, or how consistently it would occur.

The 2008 experiment also leaves human safety unresolved because it measured testicular effects only in rats.

Controlled human trials would be needed to determine whether Fadogia agrestis meaningfully increases testosterone in men and whether repeated use is safe.

Can the Rat Doses Be Converted Into a Supplement Dose?

The doses used in these studies should not be treated as instructions for taking a commercial Fadogia agrestis supplement.

The researchers prepared their own aqueous extract from dried plant stems. Commercial products may differ in plant material, extraction method, concentration, and composition.

The studies also tested rats rather than humans. A dose expressed in milligrams per kilogram in a rat experiment is not automatically equivalent to the same milligrams per kilogram in a person.

Neither paper established a human dose for increasing testosterone.

Bottom Line

Fadogia agrestis increased testosterone in male rats, with the largest rise occurring at the highest dose tested. The evidence for that effect comes from one short-term animal experiment.

A later 28-day rat study found changes in multiple biochemical markers of testicular function, with incomplete recovery of some measurements after treatment stopped. Whether either the testosterone effect or the testicular changes occurs in humans remains unknown.

On the available evidence, Fadogia agrestis has not been established as a testosterone booster for people.

References

Yakubu, M. T., Akanji, M. A., & Oladiji, A. T. (2005). Aphrodisiac potentials of the aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male albino rats. Asian Journal of Andrology, 7(4), 399–404. https://doi.org/10.1111/j.1745-7262.2005.00052.x

Yakubu, M. T., Akanji, M. A., & Oladiji, A. T. (2008). Effects of oral administration of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem on some testicular function indices of male rats. Journal of Ethnopharmacology, 115(2), 288–292. https://doi.org/10.1016/j.jep.2007.10.004