It sounds like a clash of two South American boxing titans; Bulbine Natalensis vs. Tribulus Terrestris.
Both derived from plants already known to boast powerful aphrodisiac properties and demonstrated to be effective at boosting testosterone levels in animal studies, Bulbine Natalensis and Tribulus Terrestris are two of the biggest names in botanical hormone boosting supplements on the market.
In this guide, we take a look at the science behind the claims and provide as much evidence about the efficacy of each.
Head to Head: The Comparison
|Bulbine Natalensis||Tribulus Terrestris|
|Type||Plant Extract||Plant Extract|
|Active ingredients||Steroidal saponins, tannins, alkaloids, cardiac glycosides and anthraquinones||Steroidal Saponins
|Health Claims||Boosts testosterone and acts as an aphrodisiac to boost libido||Improve erectile function, boost libido, testosterone, stamina and strength as well as support healthy immune and urinary system|
What is Bulbine Natalensis?
A South African herb used in traditional medicine to treat anything from mosquito bites to sunburn as a topical application and nausea to diarrhoea as an internal solution, bulbine natalensis is a relatively new player in the sports supplement market.
Bulbine Natalensis consists of steroidal saponins, tannins, alkaloids, cardiac glycosides and anthraquinones.
What does Bulbine Natalensis claim to do?
Research has recently suggested that this potent plant extract can boost libido and testosterone as well as reduce the amount of oestrogen produced by our bodies.
In animal studies, Bulbine Natalensis has been shown to be an effective libido enhancer, outperforming Viagra.
Does Bulbine Natalensis boost testosterone levels?
Animal studies that have been undertaken do show a positive effect on testosterone levels with increases of 346% being reported with a correlative decrease in oestrogen by 35%. This was recorded at doses of 50mg/kg in rats.
However, the research has also shown that these effects are dose dependent with too much Bulbine Natalensis actually producing the reverse effect, having a toxicological bell curve. At doses of 100mg/kg the effect was the same as doses of 25mg/kg or lower; in some instances, actually decreasing testosterone levels below that of the control group.
As yet, the limited number of human studies undertaken have either failed to reproduce these results or shown no impact on testosterone levels at all.
The Dangers of Bulbine Natalensis
There is evidence from the limited studies undertaken on Bulbine Natalensis to suggest that there is a toxic effect, specifically relating to the liver. This is largely due to a series of trials performed on rats where the lipid profile in test subjects at therapeutic doses of 25-100 mg/kg were seen to mimic steroid cycles. Observations were reported of raised HDL cholesterol levels and triglycerides.
Additional studies also reported distortions in the architecture of the kidneys in otherwise healthy rats post-study.
Bulbine Natalensis: Summary
Though the claims of testosterone boosting properties are encouraging the benefits in humans is yet to be determined though anecdotal evidence suggests that results are comparable. However, the dangers of the toxicity of this plant in either animal or human studies is yet to be determined with the safety of long term use being unknown.
What is Tribulus Terrestris?
Used in traditional medicine across Asia, America, Africa and Australia, Tribulus Terrestris is more commonly known as bullweed, devils weed and puncture vine.
It has been used as a herbal extract to treat conditions from angina to anaemia, digestive disorders to flatulence. Used for centuries, there is very little evidence of any side effects to this herb.
What does Tribulus Terrestris claim to do?
In modern markets, tribulus terrestris is claimed to treat erectile dysfunction and boost the libido with potent and proven results. In recent years, supporters of this supplement have also claimed that it provides a boost to testosterone levels and enhances muscular strength and stamina. In some circles, users claim report similar effects to that of anabolic steroids.
What’s the science behind Tribulus Terrestris?
Tribulus terrestris contains steroidal saponins, lignin amides, flavonoids, alkaloids and glycosides.
There is evidence that supports the claim that steroidal saponins have a potent effect on mimicking the behaviour of naturally occurring human growth hormones such as testosterone.
The main saponins in tribulus terrestris is protodioscin which is a compound proven to significantly increase testosterone levels in animal studies and stimulate the libido.
Research on tribulus has also been used effectively to treat diabetes, decrease blood pressure, as an effective diuretic and pain-killer and to treat depression.
Does Tribulus Terrestris boost testosterone levels?
There is no doubting that the active ingredients in tribulus terrestris have worked very effectively in animal studies (including primates) to boost testosterone levels by as much as 52%.
However, there is yet to be a conclusive study that is widely accepted by the scientific community that these results can be replicated in humans.
Two trials do produce supportive evidence for the claims that tribulus terrestris boost testosterone levels with marked improvements seen in both athletes and healthy young males.
That said, several other trials have also produced findings that testosterone levels can be boosted by tribulus though the increases seen in these, of 16%, were deemed ‘insignificant’.
Detractors of the few human trials undertaken suggest that the results are flawed as there is often a conflict of interest in the sponsors of the studies with positive findings on the testosterone boosting properties of tribulus or that the test subjects are often suffering from erectile dysfunction or have impaired testosterone production.
Is Tribulus Terrestris Safe?
There are no toxic effects reported with the use of tribulus terrestris at therapeutic doses.
Tribulus Terrestris: Summary
The power of tribulus terrestris to boost libido and enhance testosterone levels in animal studies is irrefutable and there is certainly evidence to suggest that this is also true in humans although further research is needed on the doses required to support this.