Podcast episode 134 (in German)
Tongkat Ali and Fadogia – one plant tested, one not
November 11, 2026
Tongkat Ali and Fadogia are usually sold as a pair, yet only one of the two plants has ever been studied in humans. The episode shows what the root actually changes in men with low testosterone — and why a blood test can be a better first step than the capsule.
What it is about
Tongkat Ali is the root of a slow-growing tree from Southeast Asia, Fadogia agrestis a West African shrub related to coffee; both are considered testosterone plants. For the root there are randomized trials: in men with low levels, testosterone rises measurably but modestly, while in the largest study in healthy men the blood level stayed the same. What is interesting is that the questionnaires still show movement, in erectile function, resilience, fatigue and tension. A British survey shows why so many men reach for the root in the first place: symptoms are common, diagnoses rare. For Fadogia, by contrast, there are only rat experiments. The episode ends not with a buying recommendation but with the question of whether one’s own level has ever been measured.
Key points
- A 2022 meta-analysis pooled 5 randomized trials with 232 men: overall, testosterone rose significantly, but not in men with normal baseline levels.
- In the cleanest single study, double-blind in 105 men aged 50 to 70 over 12 weeks, the level rose from about 200 to 225 nanograms per deciliter; the study itself draws the line at 300.
- The largest study in healthy men, 109 participants over 12 weeks, found no difference from placebo in testosterone, but better erectile function and resilience in the questionnaires.
- The explanation on many packages, that Tongkat frees up testosterone, was checked in 32 young men: the transport protein and the regulating hormones from the pituitary gland remained unchanged.
- The advertising figures come from a study of 76 men without a placebo group and from a 37 percent increase in saliva, in men and women combined, paid for by the manufacturer.
- In a British survey of 973 men, so far available as a preprint, almost half had symptoms consistent with low testosterone; 4 percent had been diagnosed.
- For Fadogia there are only rat experiments: after 5 days testosterone rose, after 28 days the testicular values shifted toward damage; 5 of 17 products contained no detectable plant compounds.
Where the data stop
Almost all human data on Tongkat are tied to one Malaysian manufacturer: 7 of the 9 studies in the meta-analysis used the same extract, and the studies with the questionnaires are also close to the manufacturer. Heterogeneity between the studies was 87 percent, and there were also signs that unfavorable results were published less often. Whether a powder from the internet is the same thing, nobody knows; in 2018, only 37 percent of samples in a genetic test clearly contained the right plant. Nothing was tested for longer than a few months, and there are case reports concerning the liver and heart rhythm as well as a documented interaction with the beta blocker propranolol.
Questionnaires measure how someone is doing, and that is a finding in its own right alongside the lab value; expectation, however, has a stronger effect there than in the blood. There is no systematic count of forum reports. For Fadogia there is no study in humans at all, and the same goes for the combination. Neither plant is approved in the EU, and a low testosterone level is a medical diagnosis.
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Published on November 11, 2026.
The topic in the database
- Root extract from Southeast Asia: in men with low testosterone, several studies show a small increase, in healthy men nothing significant…Tongkat Ali
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-23.