Testosterone boosters today contain all kinds of weird and exotic-sounding ingredients. Looking at the label of your average test booster can feel like you’re looking at a different language; many manufacturers purposefully use the chemical or Latin names for commonplace substances to make their product seem more exciting.
On top of that, there’s the problem of manufacturers outright lying. Every single testosterone booster on the market today claims to have a special, unique, powerful formula. They say that their ingredients have all been “scientifically-proven” to raise free serum testosterone levels. Some of them make spectacular claims, like being as powerful as anabolic steroids, or being a viable alternative to TRT.
But we know that most of this is total BS.
The weird and wonderful substances used in testosterone boosters today number in the hundreds. Yet only a handful actually have any demonstrable effect on free serum testosterone levels in men suffering from low testosterone. An even smaller number have been scientifically shown to raise test in healthy young men.
How are you supposed to know the good ingredients from the bad?
How can you possibly be expected to keep up with all the research being done on these substances?
The simple answer is, you can’t. But you don’t need to; you have us!
Below you will find a list of the most commonly used ingredients in natural testosterone boosters. We’ve covered the good and the bad. Instead of just telling you what we think and then linking studies to back up our pre-existing opinions, we’ve listed the key studies published on that ingredients, a quick overview of what they found, and what their limitations were. We’ve also given you a conclusive opinion on whether the ingredient works or not.
Testosterone Booster Ingredient Guide
Below you will find all of the most commonly used ingredients in testosterone boosters today. We’ve cited some of the best, most robust scientific studies done on the substance. We’ve cited studies both for and against the use of the ingredient as a natural testosterone booster.
To make your research quick and easy, we’ve stated whether or not we think the substance works or not right next to the name.
That’s enough of a preamble.
LET’S GET TO IT!
D-Aspartic Acid – LEGIT
- This study looked at how D-Aspartic Acid supplementation works in humans and rats. The researchers gave 23 men a potent D-Aspartic Acid supplement and 20 men a placebo for 12 days. A similar study was done in parallel on rats. Serum Luteinizing Hormone and testosterone levels were measured. The researchers concluded: “In humans and rats, sodium D-aspartate induces an enhancement of LH and testosterone release…In the pituitary and in testes D-Asp is synthesized by a D-aspartate racemase which convert L-Asp into D-Asp. The pituitary and testes possesses a high capacity to trapping circulating D-Asp from hexogen or endogen sources.” (Published 2009 in Reproductive Biology & Endocrinology).
- This study is probably the most commonly cited in support of D-AA as a testosterone booster. It is indeed the most encouraging. Researchers were evaluating the efficacy of D-AA as a treatment for poor sperm motility. They were mainly looking at semen, but the blood analysis of the participants taking D-AA showed a 30-60% increase in serum LH and testosterone levels, respectively! The paper’s authors state: “The only variation was found to be in the LH and testosterone concentrations that were found to be increased between 1.3 – 1.6 fold compared to their basal levels in the Daspartate group. However, the increased levels of LH and testosterone observed in this study were in agreement with the previously reported results demonstrating that D-aspartate has the capacity to increase LH and testosterone blood levels.” (Published 2012 in Advances in Sexual Medicine).
However, the study of D-Aspartic Acid and testosterone has not always thrown up such straightforward results. Many studies have found that D-AA supplementation does very little for free serum testosterone levels. One study even found that it can decrease serum testosterone!
- A very interesting – and often overlooked – study found that large quantities of D-AA led to a significant decrease in serum testosterone concentrations. A group of 24 men, all resistance trained, were given either 6g of D-AA, 3g of D-AA, or placebo. The test ran for 14 days. The findings are completely at odds with the studies listed above: “The present study demonstrated that a daily dose of six grams of d-aspartic acid decreased levels of total testosterone and free testosterone (D6), without any concurrent change in other hormones measured. Three grams of d-aspartic acid had no significant effect on either testosterone markers. It is currently unknown what effect this reduction in testosterone will have on strength and hypertrophy gains.” (Published 2015 in the Journal of the International Society of Sports Nutrition).
This is a very worrying finding. However, in our opinion, this is the outlier in the sample group. Far more studies seem to show that D-Aspartic Acid supplementation reliably increases free serum testosterone in healthy young men and men suffering with low testosterone. The 2015 study discussed above only went on for 14 days, and the sample size was small. While we must take its conclusions seriously, we think the weight of the evidence pulls us in one clear direction.
D-Aspartic Acid works well for most men. If you try it and you think your testosterone levels might be falling, cease use and go see a doctor!
Vitamin D – LEGIT
- This trial looked at the correlation between Vitamin D levels, total testosterone, and free testosterone levels in over 600 middle-aged Korean men. The findings of this study are conclusive and convincing, so we’ll just let them speak for themselves: “A vitamin D deficiency [25(OH)D < 20 ng ml−1 ] was associated with an increased risk of deficiencies of TT (<2.30 ng ml−1 ) (odds ratio [OR]: 2.65; 95% confidence interval [CI]: 1.21-5.78, P= 0.014) and FT (<6.50 pg ml−1 ) (OR: 1.44; 95% CI: 1.01-2.06 P= 0.048) after adjusting for age, season, body mass index, body composition, chronic disease, smoking, and alcohol use. In conclusion, we demonstrated a positive correlation between 25(OH)D and testosterone, which showed similar seasonal variation in Korean men.” That is one strong correlation! (Published 2015 in the Asian Journal of Andrology).
- Another, even larger, study conducted on German men reached the same conclusions. Here, 2,299 men who were selected randomly from patients sent for a certain procedure. We’ll again let the results and the conclusions drawn by the authors speak for themselves: “In linear regression analyses adjusted for possible confounders, we found significant associations of 25(OH)D levels with testosterone, Free Androgen Index and SHBG levels (P < 0.05 for all)…Androgen levels and 25(OH)D levels are associated in men and reveal a concordant seasonal variation. Randomized controlled trials are warranted to evaluate the effect of vitamin D supplementation on androgen levels.” (Published 2010 in Clinical Endocrinology).
You might have noticed that these studies were fairly short term. However, Vitamin D has been extensively studied in long-term clinical trials.
- This clinical trial took 165 overweight but otherwise healthy men and measured how Vitamin D supplementation affected testosterone levels. We’ll quote the abstract at length: “Participants received either 83 μg (3,332 IU) vitamin D daily for 1 year or placebo. Initial 25(OH)D concentrations were in the deficiency range (< 50 nmol/l) and testosterone values were at the lower end of the reference range in both groups. Mean circulating 25(OH)D concentrations increased significantly by 53.5 nmol/l in the vitamin D group, but remained almost constant in the placebo group. Compared to baseline values, a significant increase in total testosterone levels, bioactive testosterone, and free testosterone levels (from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l; p = 0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group.” (Published 2011 in Hormone & Metabolic Research).
We believe that Vitamin D has been thoroughly proven to positively influence free and total testosterone levels. The exact mechanism is difficult to identify. Vitamin D certainly behaves more like a hormone in the body. There is a strong correlation between Vitamin D levels and testosterone levels; in almost all studies, high Vitamin D levels means high testosterone levels, and low Vitamin D means low testosterone. Some studies seem to indicate that Vitamin D might act as a SHBG binder.
Until research identifies exactly how Vitamin D affects testosterone levels, we’re in the dark. But it is quite clear that Vitamin D supplementation reliably increases free and total testosterone in healthy, obese, and older men. The correlation is strong across cultures and geographies.
Tribulus Terrestris – BOGUS
- One clinical trial looked at Tribulus Terrestris supplementation in healthy men. The study took 21 men aged 20-36, all of a healthy weight, and split them into three groups. One group received 20mg of TT per kg of body-weight, another 10mg/kg bw, and the other 7 a placebo for a total of 24 days. The results showed quite clearly that Tribulus Terrestris does not increase free serum testosterone in healthy young men. The authors conclude: “There was no significant difference between Tribulus terrestris supplemented groups and controls in the serum testosterone”. (Published 2005 in the Journal of Ethnopharmacology).
- One of the most important studies you need to look at when investigating Tribulus Terrestris is this one. You will find this study talked about in any honest analysis of TT. Researchers took 22 elite Australian rugby players undergoing intensive pre-season training. The rugby players were either given 450mg of TT per day or a placebo. An extreme weight training regime should deplete testosterone levels, so the researchers were looking to see if TT preserved them. They were seriously disappointed: “No between-group differences were noted in the urinary T/E ratio. It was concluded that T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5-28 days. Furthermore, T. terrestris did not alter the urinary T/E ratio and would not place an athlete at risk of testing positive based on the World Anti-Doping Agency’s urinary T/E ratio limit of 4:1.” (Published 2007 in the Journal of Strength & Conditioning Research).
We think it’s plainly clear that Tribulus Terrestris doesn’t boost testosterone levels as many supplement manufacturers claim. We are yet to see a study countering the findings of the two studies cited above. But there are plenty of others showing Tribulus Terrestris doing absolutely nothing for testosterone.
There’s really no argument here! Tribulus Terrestris is bogus!
Ginseng – LEGIT
- This clinical investigation is one of the most promising studies looking at ginseng supplementation and testosterone. Researchers from the University of Rome La Sapienza took 66 men, gave them ginseng, and then measured everything from sperm motility to total testosterone levels. Their conclusion reads as follows: “Use of Panax Ginseng extract showed an increase in spermatozoa number/ml and progressive oscillating motility, an increase in plasma total and free testosterone, DHT, FSH and LH levels, but a decrease in mean PRL. It is suggested that ginsenosides may have an effect at different levels of the hypothalamus-pituitary-testis axis.” This last point is interesting; it seems that ginseng affects very particular parts of the hypothalamus, pituitary gland, and the testes – those most directly related to fertility. This bodes well for the safety of the supplement. (Published 1996 in Panmanerva Medica).
- An earlier study seems to show precisely the same thing; ginseng supplementation reliably increases serum testosterone. In this clinical trial, male rats were given either 1% or 5% preparations of Panax Ginseng for 60 days. A control group was also used. Interestingly, only the rats fed the 5% preparation experienced any rise in testosterone levels. However, that rise was large: “Rats that received 5% ginseng experienced a significant increase in blood testosterone level (rho less than 0.001). Prostate weight in the treated animals was significantly reduced as compared to the control animals.” (Published 1982 in Arichives of Andrology).
Yet there are other studies showing little to no effect from ginseng supplementation. What these studies suggest to us is that the dosage, potency, and type of ginseng being used is extremely important in determining how effective it is going to be at raising testosterone levels.
- This fascinating study looked at whether ginseng saponin components prevent the development of this copulatory disorder (when male rats just stop having sex). The findings of this study might be massive for the testosterone booster industry, so it is worth quoting the absrtact in full: “The following constituents of red ginseng powder were administered intraperitoneally once per day throughout the individual housing period: crude ginseng saponins and pure ginsenoside Rb1, Rb2, Rg1, and Ro. Three elements of copulatory behavior (mounting, intromission and penis licking) were determined. Following prolonged individual housing only one mouse in the vehicle-treated group displayed mounting. Chronic treatment with crude ginseng saponins (25, 50 and 100 mg/kg) significantly lessened the severity of copulatory disorder in a dose-dependent manner. Ginsenoside Rg1 (2.5, 5 and 10 mg/kg) also resulted in a significantly higher incidence of copulatory behavior as compared to the individually housed vehicle-treated group, whereas ginsenoside Rb1, Rb2 and Ro were ineffective. This evidence indicates that ginsenoside Rg1 is one of the ingredients of red ginseng root that acts on male copulatory behavior.” (Published 1998 in Methods and Findings in Experimental and Clinical Pharmacology).
Ginseng – in its various forms – is a very common addition to natural testosterone boosters today. It is often added to herbal teas and health smoothies because of its ability to boost vitality. As we’ve seen, ginseng is definitely capable of having a positive effect on testosterone levels.
However, not all ginseng is equally capable of affecting your hormones. Some do it far more than others. The exact composition of ginsenosides in the extract or plant being used will determine its ultimate efficacy. Dosage is also a very important variable. If you read the cited studies, you’ll get a good idea for how much ginseng needs to be consumed to have a sizable effect.
Ultimately, you need to accept that ginseng is extremely unreliable. Some manufacturers would have you believe that it is basically nature’s TRT (testosterone replacement therapy). It isn’t.
It has a real but modest impact on hormonal parameters. It sometimes works remarkably well, and in other circumstances it doesn’t work at all.
Luteolin – LEGIT
- Luteolin appears to act as a powerful, natural aromatase inhibitor. This interesting clinical investigation looked at a number of different substances thought to act as natural aromatase inhibitors. The researchers looked at each substance individually, measuring how much it appeared to inhibit the action of the enzyme in vitro. The researchers point out that luteolin seems to act as a strong aromatase inhibitor: “When comparing aromatase inhibitory activity within the flavone compound class, several trends become apparent. Hydroxyl groups at positions 5, 7, and 4′ generally increase aromatase inhibition activity [e.g., as in…luteolin (31)…]”. (Published 2008 in Anticancer Agents in Medicinal Chemistry).
- This much more convincing study seems to strongly confirm these findings. We strongly recommend reading this paper if you are interested in pursuing aromatase inhibition without resorting to pharmaceuticals. The researchers here identified the mechanisms behind luteolin’s action: “Luteolin decreased aromatase mRNA and protein expression in KGN cells. Luteolin also promoted aromatase protein degradation and inhibited estrogen biosynthesis in aromatase-expressing HEK293A cells, but had no effect on recombinant expressed aromatase.” The authors of the paper were confident enough to publish their findings more emphatically: “The present study suggests that luteolin inhibits estrogen biosynthesis by decreasing aromatase expression and destabilizing aromatase protein”. (Published 2012 in the Journal of Agricultural and Food Chemistry).
- One final study we think you should check out is this one. Here, researchers were looking to see if luteolin administration helped to minimize the side effects of the drug Letrozole (which is used to treat breast cancer by reducing aromatase activity). They did indeed find what they were looking for; luteolin supplementation reduced the side effects of the drug. However, they also found that luteolin had similar effects to Letrozole: “Similar to letrozole, luteolin administration reduced plasma estrogen concentrations and suppressed the xenograft proliferation…In contrast to letrozole, luteolin increased fasting plasma high-density lipoprotein concentrations and produced a desirable blood lipid profile.” This obviously needs further study, and the researchers did not suggest that luteolin was preferable to Letrozole for the treatment of breast cancer. Not at all. But it is definitely an interesting finding worthy of further study!
This is a no-brainer for us. We’re not aware of any other natural substance which has such proven aromatase inhibitory power. The fact that it has been found to work well in so many studies, and with such resounding success in each case, speaks volumes.
We think every testosterone booster should contain a decent serving of luteolin. Few natural substances have such a sound scientific pedigree. None seem to work in quite the same way.
By stacking things that promote testosterone synthesis and release with luteolin, you can get results that are far more significant than using either substance alone. You will be, in effect, tackling both sides of the problem.
Maca Root – BOGUS
- In this clinical trial, fourteen postmenopausal women were given 3.5 g of powered Maca per day for 6 weeks and matching placebo for 6 weeks, in either order, over a total of 12 weeks. The researchers were specifically looking at Maca’s ability to influence hormonal parameters in humans. One of the central claims that supplement manufacturers make about Maca is that it stimulates LH release, just like D-Aspartic Acid. But this study blows this assertion right out the water: “No differences were seen in serum concentrations of estradiol, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin between baseline, Maca treatment, and placebo (P > 0.05)”. (Published 2008 in Menopause).
- Another common assertion about Maca is that it improves sexual desire. The implication is that it must also increase testosterone levels, as the two usually go hand in hand. However, this study directly counters this claim. We’ll let the authors explain themselves: “Men aged 21-56 years received Maca in one of two doses: 1,500 mg or 3,000 mg or placebo. Self-perception on sexual desire, score for Hamilton test for depression, and Hamilton test for anxiety were measured at 4, 8 and 12 weeks of treatment. An improvement in sexual desire was observed with Maca since 8 weeks of treatment. Serum testosterone and oestradiol levels were not different in men treated with Maca and in those treated with placebo (P:NS). Logistic regression analysis showed that Maca has an independent effect on sexual desire at 8 and 12 weeks of treatment, and this effect is not because of changes in either Hamilton scores for depression or anxiety or serum testosterone and oestradiol levels.” That’s convincing enough for us! (Published 2002 in Andrologia).
- It is worth highlighting one final study to really drive this point home. In this trial, researchers gave large doses of Maca Root powder (1.5g – 3g daily) to men aged between 21 and 56. The findings were similar to those reported in the studies above: “Serum levels of luteinizing hormone, follicle-stimulating hormone, prolactin, 17-alpha hydroxyprogesterone, testosterone and 17-beta estradiol were measured before and at 2, 4, 8 and 12 weeks of treatment with placebo or Maca (1.5 g or 3.0 g per day). Data showed that compared with placebo Maca had no effect on any of the hormones studied nor did the hormones show any changes over time. Multiple regression analysis showed that serum testosterone levels were not affected by treatment with Maca at any of the times studied (P, not significant). In conclusion, treatment with Maca does not affect serum reproductive hormone levels.” (Published 2003 in the Journal of Endocrinology).
It should be clear to you now that Maca Root does absolutely nothing for testosterone levels. It doesn’t even work for specific populations of conditions; the studies above looked at men and women of very different ages, yet the conclusions were all the same: no effect on testosterone was observed.
Supplement manufacturers will tell you that Maca Root has been proven to increase testosterone in men. They will then point you to a study showing that it increases libido. But increase libido is not the same as increasing serum testosterone! The studies actually all state that Maca Root improves sexual desire independently of hormonal parameters.
If you are just interested in spicing up your sex life and regaining some of your old ‘appetite’, then Maca Root might be worth a try. But if you want to increase testosterone itself, don’t bother!
Magnesium – LEGIT
- This paper should be a required text when looking at magnesium and testosterone’s relationship. In it, researchers explain that serum magnesium levels are closely correlated with anabolic hormone levels in older men; higher magnesium levels in the blood always correlate with higher free and total testosterone levels (as well as higher levels of other anabolic hormones). The actual results are worth looking at: “After adjusting for age, magnesium was positively associated with total testosterone (β ± SE, 34.9 ± 10.3; p = 0.001) and with total IGF-1 (β ± SE, 15.9 ± 4.8; p = 0.001). After further adjustment for body mass index (BMI), log (IL-6), log (DHEAS), log (SHBG), log (insulin), total IGF-1, grip strength, Parkinson’s disease and chronic heart failure, the relationship between magnesium and total testosterone remained strong and highly significant (β ± SE, 48.72 ± 12.61; p = 0.001)”. (Published 2011 in the International Journal of Andrology).
Here is a graph showing the researchers’ findings. It shows the relationship between serum magnesium levels and serum testosterone levels, adjusted for age:
- It is also worth reading the studies conducted on younger, healthy, physically fit men. In this study, researchers looked at how 4 weeks of magnesium supplementation affected the hormone profiles of young tae kwon do practitioners, with sedentary controls to measure testosterone at rest and post-exercise. The findings are again worth quoting in full: “The free plasma testosterone levels increased at exhaustion before and after supplementation compared to resting levels. Exercise also increased testosterone levels relative to sedentary subjects. Similar increases were observed for total testosterone. Our results show that supplementation with magnesium increases free and total testosterone values in sedentary and in athletes. The increases are higher in those who exercise than in sedentary individuals.” (Published 2011 in Biological Trace Element Research).
Magnesium is one of the most common ingredients in natural testosterone boosters. It is actually one of the most commonly used supplements among natural bodybuilders and enhanced athletes alike. It has long been prized for its ability to support healthy testosterone levels – crucial when the body is being subjected to heavy weight training for long periods of time. The current scientific consensus is that this is not ‘broscience’ or hearsay; magnesium really works, and it works extremely well!
We now understand how magnesium affects testosterone levels in the human body. We know that a magnesium deficiency is almost always followed by a sharp drop in free and total serum testosterone levels. It is also quite clear that fixing a magnesium deficiency through supplementation generally leads to a sharp rise in serum testosterone levels.
Supplemental magnesium also seem to enhance the increase in serum testosterone observed in healthy young men post-exercise.
This stuff has been a staple for decades for a reason – it works! It should be in every testosterone booster as standard. There isn’t much of a toxicity concern here, and few people get anywhere near enough in their diets. While you should strive to get plenty from food, we think a good supplement should provide a healthy dose.
Learn more from our testosterone booster buying guide.
See our list of the best testosterone boosters in the UK.