Bulbine natalensis
Rooiwortel / 'Ibhucu' (Asphodelaceae)
Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Not FDA evaluated; sold as a bodybuilding supplement
Reference only. Not medical advice.
What can go wrong
Rodent data show dose-dependent hepatotoxicity, nephrotoxicity, and adverse lipid changes; anthraquinone content raises additional concern. No human safety dataset exists. Anyone treating this as a benign 'natural test booster' is extrapolating from rat studies that themselves flagged organ damage.
This is something to take to a clinician. The Atlas can tell you what is known about bulbine natalensis in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Bulbine natalensis is a succulent used in traditional Zulu/Xhosa medicine for various complaints. It entered the Western supplement market almost entirely on the back of a series of rat studies from Yakubu and colleagues (University of Fort Hare / Ladoke Akintola) reporting increased serum testosterone, raised mounting/intromission frequency, and penile-tissue changes at certain doses. Those same researchers also reported dose-dependent liver and kidney toxicity and altered lipid profiles in rats. There are essentially no human RCTs. The supplement industry quotes the testosterone findings while omitting the organ-toxicity findings from the identical studies.
A Zulu medicinal succulent that became a bodybuilding 'test booster' on the strength of rat studies.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
Combinations named above are how people use these compounds together, under names the community gave them. The combinations themselves have not been studied. Evidence for one compound is not evidence for a pair.
How it is supposed to work
Mechanism is unproven. Rodent work attributes effects to saponins and other glycosides hypothesized to stimulate Leydig-cell steroidogenesis and luteinizing-hormone-like activity, raising serum testosterone. None of this has been demonstrated in humans, and the magnitude and even direction of any human hormonal effect is unknown.
Contains anthraquinones (knipholone and related compounds), phytosterols, saponins, and glycosides typical of the genus. The marketed material is usually a 10:1 or similar leaf/root extract of variable composition.
The pro-testosterone study is also a hepatotoxicity study
The widely cited paper that supplement labels lean on (Yakubu & Afolayan) reported that at a higher dose Bulbine natalensis raised liver and kidney enzyme markers and disturbed lipids in rats. The 'testosterone up' headline and the 'organ toxicity' finding come from the same animal experiments.
Safety in detail
- Rat studies reported elevated ALT/AST and renal markers at higher doses
- Anthraquinones can be hepatotoxic and laxative
- No human pharmacovigilance data
- Quality and extract ratio vary widely between brands
What people get wrong
Often saidClinically proven to raise testosterone
ActuallyThe 'proof' is rat data from one research group. No randomized human trial has shown a testosterone or erectile benefit in men.
Often saidA safe herbal alternative to TRT
ActuallyThe foundational rodent studies themselves documented liver and kidney toxicity; calling it safe contradicts its own evidence base.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
How we got here
Long used in southern African folk medicine (the broader genus Bulbine is a common burn and wound remedy). Its career as a 'test booster' is recent and almost wholly Western, driven by bodybuilding forums and supplement marketers who discovered the Yakubu rat papers in the late 2000s.
The people taking it
Cultivated and wild-harvested in South Africa; sold globally as capsules and extracts by sports-nutrition brands. Commonly stacked with Tongkat Ali, Tribulus, and fadogia in 'natural testosterone' products.
What we do not know
- Does Bulbine natalensis change testosterone in humans at all?
- What is the human hepatic safety margin given the rodent toxicity signal?
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Sold as 10:1-type leaf extracts with no enforced standardization marker; identity testing is rare and substitution with other Bulbine or aloe-family succulents is plausible.
At a glance
- Family
- Asphodelaceae
- Origin
- South Africa (KwaZulu-Natal)
- Active classes
- Anthraquinones, saponins, glycosides
- Key evidence base
- Rat studies (Yakubu et al.)
- Human RCTs
- Effectively none
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Bulbine natalensis. A short entry is not a safe entry.
- Timeline. We have not built the dated record of research and regulatory events.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Yakubu & Afolayan, Bulbine natalensis on male rat sexual behaviour2009
Reported increased mounting, intromission and serum testosterone at 25-50 mg/kg in rats
Yakubu & Afolayan, toxicity evaluation2009-2010
Reported dose-dependent hepatic and renal toxicity and lipid changes at higher rodent doses