Testosterone Fakes: An Analysis of Supplement Efficacy

Around the age of 30, testosterone levels drop by about 1% per year. At age 75, serum testosterone is on average 35% lower and free testosterone 50-60% lower compared to what it was at age 25.

On online shops such as amazon- and, supplements are sold that claim to increase your testosterone levels. Known as testosterone boosters, these supplements claim toimprove sportperformance and increase your strength and muscle mass.

Unsurprisingly, evidence to back up these claims is never provided. So it' s high time we found out for ourselves.

What you can expect

To assess a treatment, we have collected and analyzed multiple scientific studies. A treatment assessed as ineffective, is really ineffective. Vice versa this also applies.

To keep the guide compact and readable, the analysis for each treatment is summarized in a few sentences. For a complete overview of the research results, please see the attached articles and scientific references.


D-Aspartic Acid

Includes a large number of studies, but most are of low quality. Human trials are limited - 4 in total.

D-Aspartic increases testosterone production in animals, but data in humans is contradictory. In one study D-Aspartic Acid increased testosterone, but two other studies found no effect. The last study found no effect on Testosterone at a dose of 3 gr/d, but a decrease in Testosterone at a dose of 6 gr/d.

The effectiveness of D-aspartic acid as a testosterone booster has not been proven. According to the data available, there is no reason to assume otherwise. As a testosterone boosting supplement we consider D-Aspartic Acid to be ineffective


Limited number of studies available. A total of 9 studies have been conducted on humans. Two studies found a positive effect on testosterone, while six studies found no effect. In one study the effect remained undetermined.

The effectiveness of Boron as a testosterone booster has not been proven. For increasing the testosterone we consider the product to be ineffective.


According to a meta-analysis, the drug increases testosterone in women, but not in men. For example, a dose of 150 mg/d was found to have no effect on testosterone in young men, but did in women.

The effect in women and lack of effect in men was also confirmed by the study of Morales. A dose of 50 mg/d DHEA increased serum testosterone by 203% in women, but had no effect in men.

The effect of DHEA as a testosterone booster seems to be limited to women. For men we provisionally assess the product as ineffective.


Tribulus Terrestris

Despite its popularity, the number of studies is limited.

In a 1981 study Tribulus Terrestris had a positive effect on testosterone. Two other studies with doses of 450 mg/day and 300 mg/day found no effect.

The effectiveness of Tribulus Terrestris is not proven. Studies are scarce and apart from a few studies there is no study that shows Tribulus Terrestris increases testosterone. For boosting testosterone a supplement like Tribulus Terrestris is ineffective.

Saw palmetto extract

Includes a large number of studies but the number of studies done in humans is limited.

Two studies found a positive effect on T while in six studies no effect on T was found. In the remaining two studies, the effect on Testosterone was undetermined.

The effectiveness of saw palmetto as a testosterone booster has not been proven.

Tongkat ali extract

Tongkat increases testosterone production in animals, but the number of studies on humans is limited. Three human-trial studies are available. Two studies found a positive effect on Testosterone, while the remaining study measured no effect on Testosterone.

The effectiveness of Tongkat Ali is questionable. Animal trials are promising, but conclusive data in humans is lacking.

Warning: In Malaysia, Canada, Singapore and the United States, warnings have been issued because the supplements were contaminated with substances like acetildenafil or tadalafil.

In addition, laboratory analysis reveiled that 36/100 products were found to contain more than the legally permitted amount of mercury.

Maca root extract / Maca root powder

A total of 28 studies are available, but only 4 human trials.

In three of the human trials, Maca root extract had no effect on testosterone levels. In the remaining study, Maca root extract actually decreased testosterone levels.

The efficacy of Maca root extract as a testosterone booster has not been demonstrated. We rate this supplement as ineffective.


A total of 11 studies are available, 7 of which are human trials.
In four studies, Fenugreek had a positive effect on testosterone. In the remaining three studies, the results were inconclusive.

The current studies are promising, but evidence is limited. More research is needed. As a testosteron booster, we provisionally assess this substance as product as neutral.


Limited number of studies available. Most studies are of low quality with a high risk of bias. For our analysis we included 7 studies of which 6 were RCTs and 1 RCCT. These studies were of high quality.

Only one study found that Ginseng increased testosterone, the other 6 studies found no effect.

The efficacy of Ginseng for boosting testosterone levels has not been proven. Claims that suggest the contrary are unfounded.


Limited number of studies available of which 2 human trials. Data is contradictory. One study found a positive effect, while the other found no effect.

The efficacy of Ashwagandha as a testosterone booster has not been proven. Based on the current evidence, we rate is ineffective.

Horny Goat Weed

No human trials available.
The only thing that suggests an effect on testosteron is the “clever” name.

Studies on the effect on T in humans are lacking. There is no reason to believe that Horny Goat Weed increases testosterone.

Its efficacy has not been proven. For increasing testosterone, we rate it as ineffective.



A limited number of studies are available. Zinc was often combined with magnesium or strength training so the benefits of zinc cannot be isolated.

According to a 2017 meta-analysis, zinc supplementation does not provide any benefits to Testosterone. No effect was found on either free or serum testosterone.


Vitamin D

Includes a large number of studies including some meta-analyses; a study of studies.

Vitamin D supplementation seems to be useful for older men (50+), men with poor physical health and men with vitamin D deficiency. A meta-analysis showed that Vitamin D increased testosterone in this group.

In young men without deficiency, it had no effect on testosterone. The use of a vitamin D supplement is recommended in the above risk groups. In young men without vitamin D efficiency is not proven.