Testosterone booster supplements are usually a combination of vitamins, minerals, and herbs to stimulate natural testosterone production.

I created this guide to help you separate hype from substance and filter out which ingredients are proven (in clinical trials) to boost testosterone and which ones are simply a waste of money.

Let’s get started.

Alpha Glycerophosphocholine

Alpha-GPC is a compound used for its cognitive enhancing abilities and to enhance power output in athletes

1. 8 healthy males supplementing with 1g of Alpha-GPC experienced increases in GH 60-120 minutes after ingestion (source).
2. 7 resistance-trained men supplementing with 600mg of Alpha-GPC before exercise experienced a significant spike in GH levels post-workout (source).

Although the sample sizes were small, and not much research has been done in the area, Alpha-GPC does seem to have a positive interaction with growth hormone levels.

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Anacyclus Pyrethrum (Akarkara)

Anacyclus Pyrethrum, aka Akarkara root, is an Ayurvedic herb that has traditionally been used for its purported male enhancement benefits.

It is still in the preliminary stages of research, but the following rat studies provide insight towards its potential as a testosterone booster:

a) Rats given 50-150mg/kg of Anacyclus root extract experienced a dose-dependent increase in testosterone and LH (a precursor to testosterone) by up to two-fold (precise values not given) (1).

b) Rats were given 50-100mg/kg of Anacyclus root extract experienced significant improvements in seminal parameters and sexual behavior (characterized by increased mount frequency) (2). This effect has been shown to persist up to 15-days after initial supplementation (3).

c) Rats given 50-150mg/kg of Spilanthes acmella extracts (a herb that contains the same active ingredient as Anacyclus) for 27-days experienced dose-dependent increases in testosterone by up to 115% (4).

Key Takeaway

Anacyclus Pyrethrum has been shown to enhance natural testosterone production in rats. Whether this effect carries over in humans as well remains to be seen.

Ashwagandha

Withania somnifera, commonly known as ashwagandha, is an adaptogenic herb that helps the body deal with the physical and chemical effects of stress. In Sanskrit, ashwagandha translates to the “smell of the horse,” referring to the traditional belief that ingesting the herb imparts the strength and virility of a stallion. The following research provides insight towards its impact on testosterone:

a) 57 healthy male subjects (aged 18-50) were given either a twice-daily dose of 300mg of ashwagandha root extract or placebo for 8-weeks. During this time, subjects were also put on a 3-day/week resistance training program. Compared to placebo, not only did the ashwagandha group experienced more significant increases in testosterone (2.6% vs. 15%), but they also gained more strength (as measured by bench press 1-rep max), more muscle size (as measured by arm and chest circumference), and had significantly fewer markers of exercise-induced stress (5).

b) 60 infertile male subjects given 5g of ashwagandha root powder daily for three months experienced a 10-22% increase in total testosterone (6). Seminal parameters were also significantly improved, and the pregnancy rate in the partners of the treated patients increased by 15%.

c) 75 infertile men given 3g of ashwagandha root extract for three months experienced a 14-41% increase in total testosterone (7).

Key Takeaway

Ashwagandha is a proven testosterone boosting herb that is especially effective when combined with resistance training.

Vitamin B-12

Like B-6, B12 also plays a role in a number of different bodily functions ranging from the regulation of mood to the regulation of energy levels and even maintaining brain health.

The most common use of B-12 supplementation is in addressing adrenal fatigue and impaired metabolic functions.

Again, B12 has not been studied for its direct effects on testosterone but it is definitely a plus point in terms of benefiting overall health.

Bioperine

Bioperine is a fancy term for black pepper extract.

It provides no test booster benefits on its own, but is readily added to a range of supplements for its ability to improve absorption of the primary ingredients.

Bladderwrack Extract

Bladderwrack (aka Fucus Vesiculosis) is a type of seaweed that provides a good source of iodine, i.e. the thyroid support mineral. The active compounds in Bladderwrack are known as L-Fucose.

L-Fucose compounds are generally seen to be beneficial for their anti-oxidant, anti-inflammatory, and anti-carcinogenic properties. As per the interaction with testosterone, I was unable to find any.

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Boron

Boron is a trace mineral that’s naturally present in the environment and some foods as well. Here’s the research on its interaction with testosterone:

a) Healthy male subjects given 10mg of boron daily for 7-days experienced a 28% increase in free testosterone levels (8).

b) Weightlifters were given a daily dose of 2.5mg of boron for 7-weeks. They experienced a 33% increase in total testosterone and a 15% increase in free testosterone levels (9).

c) Healthy male subjects were given 10mg of boron for 4-weeks. They experienced an 11.49% increase in total testosterone (10).

Key Takeaway

Boron has been shown in multiple human trials to have a positive influence on testosterone.

Bulbine Natalensis

Bulbine Natalensis is a herb native to southern Africa that has traditionally been used as an aphrodisiac and for its purported male enhancement benefits. Bulbine is still in the preliminary stages of research, but the following rat studies provide insight towards its potential as a testosterone booster:

a) Male rats were given 25-100mg/kg of aqueous bulbine extract for 14-days. They experienced up to a four-fold increase in testosterone (11). This effect was not dose-dependent - the 50mg/kg dose was the most effective, and the 100mg/kg dose was the least effective.

b) Scientists gave male rats 25-50mg/kg of aqueous extract of Bulbine natalensis for 7-days. The rats experienced significant improvements in sexual behavior and serum testosterone levels (12).

c) Male rats were given 25-50mg/kg of bulbine extract for 7-days. They experienced up to a 346% increase in testosterone with an inhibitory effect on estrogen taking place as well. Male rats were given 100mg/kg of bulbine. This group experienced a decrease in testosterone (13).

Key Takeaway

Bulbine Natalensis has a potent testosterone-boosting effect in rat studies and damages the liver and kidneys to the same extent as a steroid cycle.

Butea Superba

Butea Superba, aka Red Kwao Krua, is a herb from Thailand that has traditionally been used to enhance male health. The following three studies reveal insight towards its impact on testosterone:

a) Male rats given 0-200mg/kg of Butea Superba for 90-days experienced dose-dependent decreases in testosterone (at doses above 100mg/kg) (14).

b) Men with erectile dysfunction given a daily dose of 500mg of Butea Superba for 3-months experienced an 11.27% increase in testosterone as well as significant improvements in sexual parameters (15).

c) In a single case study of a 35-year old Thai man, Butea Superba reportedly skyrocketed his DHT (dihydrotestosterone) to a level way above the reference range (16). As a side-effect, this man had a significantly enhanced libido.

Key Takeaway

Although Butea Superba seems to boost libido, its influence on testosterone is unreliable. More research is needed to reach an evidence-based conclusion.

Caffeine

Although caffeine is not an ingredient added to testosterone boosters, there is a bunch of research that reveals its positive influence on T:

a) Male cyclists were put through 5-sets of 30-second sprints. 240mg of caffeine was administered in part of the experimental group following the second set of sprints. Not only did the caffeine group improve sprint performance by 5.4%, but they also had 12-14% higher testosterone levels compared to placebo (17).

b) Professional rugby players were given 0-800mg of caffeine 1-hour before a resistance training session. Placebo experienced a 15% increase in testosterone during exercise. This increase was further accentuated in the subjects supplementing with caffeine. The largest increase was 36% in the 800mg group (18). However, an important point to note is that the 800mg of caffeine also resulted in a 52% increase in cortisol. At the same time, the overall testosterone to cortisol ratio declined.

c) Professional rugby players were randomly assigned to ingest either 4mg/kg of caffeine or placebo 1-hour before exercise (which consisted of 4-sets of bench press, squat, and bent-over rows at 85% of 1-rep maximum). The athletes were further categorized into two categories: 1) sleep-deprived (<6 hours of sleep), and 2) non-sleep deprived (8+ hours of sleep). In the deprived sleep group, caffeine supplementation increased testosterone by 26.5%. In the non-sleep deprived group, caffeine supplementation increased testosterone by 30.1% (19).

d) In competitive athletes that were sleep-deprived (had been awake for 24 hours), caffeine supplementation at 6mg/kg was able to increase aerobic performance and significantly improve the testosterone to cortisol ratio (T/C) (20).

Key Takeaway

Athletic activity increases testosterone, and supplementing with caffeine is a proven way to further accentuate this acute increase. There’s no saying whether caffeine boosts testosterone without athletic activity.

Calcium

Calcium is 1 of the 22 vitamins and minerals essential for survival. You probably know it as the bone vitamin, but its influence on testosterone is also noteworthy:

a) Athletes undergoing resistance training experienced increases in testosterone, which was further accentuated with 35mg/kg of calcium supplementation (21).

Key Takeaway

Calcium supplementation has a positive influence on testosterone when combined with strength-training.

Calcium D-Glucarate

Calcium D-Glucarate is a natural substance that is largely associated with anti-oxidant benefits. It has anti-aromatase properties.

No human studies have been performed in this area, but in one animal study, rats given 10mg of Calcium D-Glucarate experienced 23% lower estrogen levels relative to control (source).

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Chromium

Chromium is found in trace amounts in pl​ants and most commonly in grains. It is an essential mineral in the human body.

Chromium regulates the breakdown of glucose for energy and also manages insulin sensitivity. Supplementing with chromium in amounts beyond what your body needs is not associated with any benefits.

The only studies that looked at the interaction between chromium and testosterone levels were performed in women with ovary conditions.

Even then, no interaction was seen.​

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Chrysin

Chrysin is a compound found in bee pollen and honey. It exploded on to the supplement scene as a testosterone booster after a couple of test-tube studies (22, 23) found that it inhibits the aromatase enzyme and allows testosterone to remain unconverted to estrogen. This claim, however, didn’t hold up in-vivo (24):

a) Rats given 50mg/kg of chrysin for 60-days experienced a 30% increase in testosterone (25).

a) 21 days of eating chrysin-rich foods failed to influence testosterone levels in men (26).

Key Takeaway

Based on the limited evidence available, chrysin fails to have an influence on testosterone levels in men.

Cordyceps

Cordyceps is a mushroom that has traditionally been used in China for its apparent anti-aging and pro-fertility properties.

Although supplementation with cordyceps has increased testosterone levels in multiple rat studies (source, source), no human studies have yet been performed in that regard.

At the current stage of research, cordyceps extract is only a potential testosterone booster.

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Creatine

Creatine is the king of bodybuilding supplements. Here’s what the research says about its impact on testosterone:

a) Elite rugby players were given 100mg/kg of creatine 1.5-hours before a passing drill. They experienced a 25% increase in testosterone (27).

b) Amateur swimmers supplementing with creatine improved their 50-m swimming time by 4.6% and had 15% higher testosterone levels than placebo (28).

c) 26 athletes (both male and female) from various sports were brought in to analyze group differences between those who supplemented with creatine and those that didn’t. Compared to the athletes who never supplemented with creatine, the athletes that had been supplementing with creatine for 1-4 years had, on average, 52.9% higher baseline testosterone levels (29).

d) College athletes going through a loading phase of creatine for 7-days (25g/day) experienced a 56% increase in DHT. Then, they went through a maintenance phase whereby they consumed 5g/day for 14-days. Even to this point, DHT levels remained elevated to 40% above baseline (30). DHT is an androgen with 3-10x the potency of testosterone.

e) College level football players were put on a 10-week resistance training program. During this time, they were randomly assigned to received either placebo, 10.5g/day of creatine, or a mixture of 10.5g/day of creatine and 3.2g/day of beta-alanine. The subjects supplementing with only creatine saw the best results in strength improvements and hormonal increases with an average increase of 22% in total testosterone and a 22.5% increase in free testosterone (31).

Key Takeaway

Creatine’s effectiveness in improving muscular performance has been consistently proven in a multitude of studies. Its impact on testosterone also seems significant.

Damiana

Damiana is a supplement derived from the dried leaves of the Turnera Diffusa plant. In Central America, it has traditionally been brewed as a tea for use as an aphrodisiac.

The evidence on Damiana is limited. There haven’t been many studies performed with it, and even the ones that have do not involve humans. A couple of rat studies (source, source) have shown aphrodisiac effects, but the rats were “sexually sluggish” to begin with. A test-tube study (source) shows Damiana to have aromatase inhibiting effects, but in no way can we conclude that the same effect will take place in humans as well.

This is the first time I’ve seen this ingredient in a testosterone supplement.

Damiana is not a proven testosterone booster.

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D-Aspartic Acid

D-Aspartic Acid (DAA) is an amino acid and a widespread ingredient in testosterone boosters. The research regarding its effectiveness, though, is questionable:

a) Healthy men given 3.12 grams of DAA for 12-days experienced a 42% increase in testosterone (32).

b) Resistance trained men supplementing with 3g of DAA while undergoing a 4-day/week training program failed to experience any testosterone changes after 28-days (33).

c) Infertile men given 2.66g of DAA for 90-days experienced significant improvements in seminal parameters, and the pregnancy rate in the partners of the men increased by 26.6%. Testosterone levels increased in the range of 30-60% (34).

d) Healthy men supplementing with 3g of DAA for 14-days failed to experienced any testosterone changes (35).

e) Resistance trained men were randomly assigned to ingest either placebo, 3g of DAA, or 6g of DAA over 4-weeks. Subjects also underwent a 4-day/week training program. No significant differences were noted between the placebo and the 3g group, but the 6g group experienced a 12.5% decrease in total testosterone and a 15.3% decrease in free testosterone (36).

Key Takeaway

Supplementing with D-Aspartic Acid may boost testosterone in the short-term (12-days), and although this increase may persist in infertile men, the evidence suggests that T returns to baseline within 28-days in otherwise healthy men.

Fenugreek

Trigonella foenum-graecum, aka fenugreek, is a herb from India that has traditionally been recommended to support male health and virility. Here’s the research on its influence on testosterone:

a) Resistance trained men given 500mg of a fenugreek supplement for 8-weeks, while on a 4-day/week training program, experienced a 12% increase in bioavailable testosterone (37).

b) 60 healthy men were given either 600mg of fenugreek or placebo for 6-weeks. The subjects receiving fenugreek experienced improved physiological aspects of libido, but testosterone levels remained unaffected (38).

c) 45 resistance-trained men were randomly assigned to ingest either 500mg of a fenugreek supplement or placebo for 8-weeks. Subjects were also put on a 4-day/week periodized training program. After 8-weeks, testosterone levels remained unaffected by fenugreek supplementation (39).

d) 49 resistance-trained men were randomly assigned to ingest either 500mg of fenugreek or placebo for 8-weeks while put on a periodized resistance training program. At the end of 8-weeks, the fenugreek group experienced a 10% decrease in free testosterone levels (40).

Key Takeaway

More evidence than not reveals that fenugreek either has no effect on testosterone or that it may even decrease free T.

Forskolin

Coleus forskohlii, aka forskolin, is yet another herb from Ayurveda that, today, is most commonly used as a fat-burner. There is also some evidence supporting its testosterone boosting abilities:

a) 30 overweight and obese men were randomly assigned to ingest either two daily doses of 250mg of forskolin or placebo for 12-weeks. At the end of 12-weeks, the forskolin group experienced an average increase of 16.77% in total testosterone (41).

Key Takeaway

The only human study on forskolin and testosterone shows a positive interaction in both obese and overweight men. More evidence is needed to confirm whether this effect carries over in men who are not overweight or obese.

ForsLean

ForsLean is a patented form of forskolin.

Forskolin is the active ingredient in the herb Coleus forskohlii.

Like ashwagandha, coleus forskohlii is also from Ayurveda (a branch of of ancient Indian herbal medicine).

It has traditionally been used to reduce inflammation, ease pain, and treat haemorrhoids. Today, it is a popular ingredient in many fat-burner and test-booster supplements.

Supplementing with forskolin elevates the levels of cAMP (cyclic adenosine monophosphate) in the body (18). Higher cAMP levels are associated with an increased rate of fat-loss.

As per its effects on testosterone, there are some test-tube studies (19, 20) that show a positive influence.

However, we can’t be sure whether these effects carry over in humans as well. The lone human study (21) I found showed forksolin supplementation to boost free T, but the impact was not significant.

At the current stage of research ForsLean is not a proven testosterone booster.

Ginger

Ginger is a spice that is readily added to food and has been used in traditional medicine in China and India. There is one study that shows its positive influence on testosterone:

a) 75 infertile men given an undisclosed amount of ginger extract for 3-months experienced a 17.7% increase in testosterone levels and significant improvements in seminal parameters as well (42).

Key Takeaway

The only human study on ginger and testosterone shows that it may boost testosterone levels in infertile men. However, this study is limited in scope because the researchers used an undisclosed amount and failed to include a double-blind control.

Ginseng

Many testosterone boosters on the market include Siberian ginseng, American ginseng, or some other patented form of the herb. But the ‘True Ginseng’ is Korean Red Ginseng (KRG), aka Panax Ginseng. This is the most researched form of the herb and what I’ll be talking about below:

a) 60 men with erectile dysfunction were randomly assigned to ingest either thrice daily doses of KRG or placebo for 12-weeks. Compared to placebo, the KRG group experienced significant improvements in penile performance with an insignificant change in testosterone (43).

b) In 66 men with low sperm motility, Panax ginseng increased testosterone and DHT (44). I was unable to get the full details of this study.

Key Takeaway

The current evidence on ginseng’s impact on testosterone is limited as it has only been performed in men with ED.

Grape Seed Extract

Grapes are great for men’s health because they contain anti-estrogenic and blood flow enhancing compounds. The only human study I found that looked at the impact of grape seed extract (GSE) on hormones was performed in women (45), but the results do not apply to men. Nonetheless, some cell-culture and rat studies provide insight:

a) Researchers have found GSE to contain potent anti-aromatase compounds (46, 47). Aromatase is the enzyme responsible for converting testosterone into estrogen - the less of it you have in your body, the more testosterone is allowed to remain unconverted.

b) Rats induced with testicular damage through high alcohol intake over 10-weeks experienced a decrease in testosterone levels by 44.2%. This decrease was reduced to 6.31% after GSE supplementation (48).

Key Takeaway

Although grape-seed extract has been shown to have anti-estrogenic and testosterone protective effects in cell-culture and rat studies, we cannot conclude that these same effects carry over in humans.

Green Tea Leaf Extract​

Green Tea Leaf extract is a powerful antioxidant that provides a bunch of health benefits including (but not limited to) improved brain function, fat-loss, and decreased risk of cancer.

As for its direct impact on testosterone, there is none.

Horny Goat Weed

Epimedium, aka Horny Goat Weed (HGW), is a herb that has traditionally been used in Chinese herbal medicine as an aphrodisiac. The active ingredient in HGW is icariin, which may have pro-erectile benefits. The human research on HGW and testosterone is limited, but the following rat studies provide insight:

a) In a group of chemically castrated rats, 200mg/kg of icariin supplementation was enough to increase testosterone levels almost triple compared to control (49).

b) In rats induced with penile injury, 1mg/kg of icariin was enough to restore testosterone levels to baseline (50).

Key Takeaway

Although horny goat weed has a positive impact on testosterone levels in rats, no human studies exist on the matter.

Maca

Lepidium meyenii, aka Maca, is a dark leafy vegetable that belongs to the broccoli family. This herb is a proven libido enhancer (51, 52) but let’s see what the research says about its influence on testosterone:

a) In 50 men with mild erectile dysfunction, 2400mg of maca supplementation for 12-weeks could not influence any hormonal parameters (53).

b) 57 male subjects given 1500-3000mg of Maca daily for 12-weeks experienced no testosterone changes compared to control (54). Another study with a very similar design revealed the same result (55).

Key Takeaway

Maca is a proven libido enhancer, but its effect on testosterone is negligible.

Magnesium

Magnesium is the fourth most abundant mineral in the human body and essential for several biological processes. As per its effects on testosterone, the following studies provide insight:

a) Magnesium supplementation at 10mg/kg increased the free testosterone levels of martial arts practitioners by up to 38% after exhaustion (56). This increase was seen in sedentary subjects as well, but not to the same extent.

b) A cross-sectional analysis of 399 elderly men found magnesium levels to be firmly and independently associated with testosterone levels (57).

Key Takeaway

Magnesium supplementation is effective at acutely boosting testosterone after strenuous exercise. In the long-term, magnesium status is independently associated with testosterone, i.e., a magnesium deficiency can lower testosterone levels.

Melatonin

Melatonin is the hormone that controls your sleep cycles.

Typically, your levels of this hormone fluctuate with the rising and setting of the sun.

If your body clock is aligned with the circadian rhythm, then your melatonin levels should rise in the morning and progressively fall as the day progresses.

Usually, 1-10mg of melatonin is taken as a sleep aid or to help with jet-lag in realigning one’s body clock. The 1mg dose in Quantum T is a good addition in the formula.

Combined with magnesium, it will increase your sleep quality and help you get into a deep state of restful sleep that will speed up recovery and allow you to wake up fresh.

Mucuna Pruriens

Mucuna Pruriens (aka Velvet Bean) is a bean that grows from trees and has traditionally been used to treat Parkinson’s disease. As per its influence on testosterone, here’s what the research tells us:

a) Infertile men were given 5g of mucuna pruriens seed powder for 3-months experienced significant improvements in seminal parameters, and a 27-39% increase in testosterone (58). Similar results were replicated in another study as well (59).

b) Infertile men given 5g of mucuna pruriens seed powder for 3-months experienced a 27-81% decrease in cortisol (60).

Key Takeaway

Mucuna Pruriens is a proven testosterone booster in infertile men. Whether this effect carries over in otherwise healthy men remains to be seen.

Niacin

Vitamin B3 refers to the compound called nicotinic acid, aka niacin. It is an essential B Vitamin, and supplementation is primarily associated with improved markers of cholesterol and triglycerides.

Although this makes it seem like niacin is supportive of cardiovascular health, there is a drawback to supplementation as well; niacin increases insulin resistance.

This is why niacin is not associated with reduced risk of cardiovascular disease.

Although it has no direct impact on testosterone, niacin is theorized to support growth, mental function, and longevity.

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Pine Pollen

Pine Pollen is an all-encompassing term that refers to the supplements derived from the pollen of pine trees. The pollen that is most commonly used in supplements comes from the Scots Pine (Pinus sylvestris) since studies have detected that it contains testosterone (61). That said, the dose of testosterone is not likely high enough to affect men’s hormonal concentrations.

Key Takeaway

The pollen from the Scots Pine contains testosterone, but there is no research to confirm whether the pollen extract’s ingestion boosts testosterone.

Polygonum cuspidatum

Japanese Knotweed, or Polygonum Cuspidatum, is a herbal medicine that has traditionally been used for circulation and heart health. The active ingredient is resveratrol, and most of its benefits can actually be tied back to that.

Although not studied directly for its impact on testosterone levels, this compound has been shown to have a significant anti-inflammatory effect (source) which could indirectly support better health and, in turn, increase testosterone levels.

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Quercetin

Quercetin is a naturally occurring compound that is most commonly found in apples and onions.

It has been shown to have powerful anti-inflammatory and antioxidant properties, anti-cancer, and anti-artherogenic qualities, but has not been thoroughly researched as per its interaction with hormones.

There is one study that showed onion juice (a rich source of quercetin) to increase testosterone levels in rats (source), but whether or not this effect carries on to affect humans in the same way still remains to be seen.

Researchers fed rats onion juice at 4g/kg of bodyweight for 20 days, after which the rats experienced significantly higher testosterone levels.

Due to a lack of human research, quercetin is only a potential testosterone booster.

Rhodiola Rosea

Rhodiola Rosea is an adaptogenic herb that’s touted for its ability to enhance cognitive and physical vitality. Research on this herb has found supplementation to be an extremely useful measure against stress and fatigue (62, 63, 64). Other than that, Rhodiola Rosea has also been shown to improve subjective well-being (65) and fight off depression (66).

Key Takeaway

Though the direct impact of this herb on testosterone has not been studied, Rhodiola Rosea may indirectly increase T-levels by reducing cortisol effects.

Royal Jelly

Royal Jelly is a substance secreted by worker honeybees and fed to larvae being raised as potential queen bees. Royal Jelly, like pine pollen, actually contains testosterone, and some studies have looked into how it can influence hormonal parameters in men:

a) Compared to placebo, men given 3000mg of royal jelly for 6-months had 14% higher testosterone levels (67).

b) Infertile men were given 25-100mg of royal jelly for 3-months experienced up to a 22% increase in testosterone (68).

Key Takeaway

Royal Jelly’s potential as a testosterone booster is promising, but the current human research is limited in scope.

Safed Musli Extract

Chlorophytum Borivilianum, aka Safed Musli, is yet another herb from Ayurvedic Medicine. It has traditionally been used as aphrodisiac and has also been found to have adaptogenic qualities.

The current research on Safed Musli involves some animal studies and only two human studies.

But the human studies use equal parts of another supplement (velvet bean) as well, so we can’t be sure of the results.

Also, the two human studies are funded by companies that manufacture the compound, so the results should be analyzed with a pinch of salt.

At this point in time, Safed Musli Extract is not a proven testosterone boosting ingredient and further research is required to draw any conclusions on it.

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Saw Palmetto

Saw Palmetto is an extract derived from the Serenoa repens plant. The extract is a mixture of fatty acids with supposed testosterone-boosting abilities. Let’s see what the research has to say:

a) A daily dose of 160mg of saw palmetto for 1-week failed to influence testosterone levels in 32 healthy male volunteers (69).

b) Men supplementing with saw palmetto (undisclosed amount) for 6-months experienced 32% lower dihydrotestosterone (DHT) levels as a result (70).

c) Men supplementing with 320mg of saw palmetto per day for 3-months had significantly higher testosterone levels and significantly lower DHT levels than the control group (71).

Key Takeaway

Saw palmetto might boost testosterone, but it does so by reducing testosterone’s conversion to dihydrotestosterone (DHT). DHT is the most potent androgen in the male body, and many of the benefits that we associate with testosterone can actually be tied back to DHT. So lower amounts of it are something we don’t want.

Shilajit

Shilajit is a thick, tar-like substance that exudes from the Himalayas’ rocky layers and other massive mountain ranges. It has been used in Ayurveda as an energy rejuvenator and anti-aging compound. As per its effects on testosterone, here’s the research:

a) Infertile men were given a twice-daily dose of 100mg of processed shilajit for 90-days experienced a 23.5% increase in testosterone (72).

b) Healthy men were given a twice-daily dose of 250mg of purified shilajit for 90-days experienced a 20.45% increase in total testosterone and a 19.14% increase in free testosterone levels (73).

Key Takeaway

Shilajit is in the preliminary stages of research, but the current human trials reveal potent testosterone boosting effects in both infertile and healthy men.

Stinging Nettle Root

Stinging Nettle is a plant that gets its name from the stinging sensation when it comes in contact with the skin. The root extract of this plant has been used since the ancient Greeks’ time as an anti-inflammatory. It is claimed to be a testosterone booster, but here’s what the lone human study says:

a) In men with benign prostatic hyperplasia (BPA), a thrice-daily dose of 120mg of stinging nettle root for 6-months was unable to influence testosterone levels (74).

Sustamine

Sustamine is the trademarked name for L-Alanyl-L-Glutamine, a combination of alanine and glutamine (two amino acids). It is commonly used as a sports supplement to improve performance. As per its effects on testosterone, there has only been one human study:

Physically active men supplementing with Sustamine were found to experience no changes in hormonal parameters after exercise (source).

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Key Takeaway

According to the lone human study published on the matter, supplementing with Stinging Nettle does not affect testosterone levels in men.

Tongkat Ali

Tongkat Ali (aka Eurycoma Longifolia Jack, Malaysian Ginseng, or Longjack) is a herb native to parts of South East Asia where it has traditionally been used to enhance aspects of male health. As per the science, here’s what the studies say:

a) 75 men with low testosterone levels were given 100mg of Tongkat Ali extract for 1-month, after which 90.8% had levels within the normal range (75).

b) 109 men were randomly assigned to ingest either a daily dose of 300mg of Tongkat Ali or placebo for 12-weeks. At the end of 12-weeks, testosterone levels in the Tongkat Ali group were about the same as placebo (76).

c) Moderately stressed men given 300mg of Tongkat Ali extract for 4-weeks experienced a 37% increase in free testosterone levels as a result (77).

d) Elderly men were given 400mg of Tongkat Ali extract for 5-weeks. They experienced a 15.1% increase in total testosterone and a 61.1% increase in free testosterone levels (78).

e) Healthy men given 200mg of Tongkat Ali extract for 12-weeks experienced a 10.36% increase in total testosterone and an 18% decrease in free testosterone levels (79)

Key Takeaway

Tongkat Ali has been shown to boost testosterone levels in men with low testosterone and men who suffer from stress. Further evidence is needed to confirm whether this effect carries over in men who do not meet these conditions.

Tribulus Terrestris

Tribulus Terrestris is a plant from Ayurvedic medicine that has traditionally been used as an aphrodisiac. It is perhaps the most popular ingredient in testosterone boosters, but the evidence behind its effectiveness is lacking:

a) Elite rugby players given 450mg of Tribulus Terrestris for 5-weeks failed to experience any changes in testosterone levels (80).

b) Healthy men given 10-20mg of Tribulus/kg of bodyweight for 4-weeks failed to experience any changes in testosterone (81)

c) Infertile men supplementing with a daily dose of 6g of Tribulus Terrestris for 60-days experienced a 16.3% increase in testosterone (82).

Key Takeaway

Tribulus Terrestris fails to influence testosterone levels in otherwise healthy men. Even in infertile men, the effect is marginal.

Velvet Antler

Velvet Antler is a crushed antler (usually from deer or elk) traditionally taken as a health supplement. There are many claims for it to having powerful testosterone boosting effect, but the science suggests otherwise:

a) Supplementing with a daily dose of 1.5g of velvet antler for 11-weeks failed to influence hormonal parameters in 38 active men (83).

b) Elderly men given a daily dose of 1g of velvet antler for 12-weeks failed to experience any changes in hormonal parameters. (84).

c) Elite rowers given 560mg of velvet antler daily for 10-weeks failed to experience hormonal or physical changes (85).

Key Takeaway

Supplementing with Velvet Antler fails to influence any hormonal parameters in men.

Vitamin D

Vitamin D, commonly referred to as the “sunshine vitamin,” is, in fact, not even a vitamin - it is a steroid hormone. Vitamin D is essential for human survival, and it regulates over 1000 bodily functions. Maintaining optimal levels of vitamin D is critical for optimal testosterone:

a) In a cross-sectional study of 2299 men, the men with sufficient vitamin D levels had significantly higher testosterone levels than the men who were deficient in it (86).

b) Healthy male subjects supplementing with 3332IU of vitamin D for 1-year had 25% higher testosterone levels than placebo (87).

c) In a cross-sectional study of 1362 men, vitamin D status and testosterone levels (both free and total) were found to be directly correlated (88). The correlation, however, plateaued when vitamin D levels surpassed 80nmol/l.

Key Takeaway

Depending on the extent of your current deficiency, supplementing with vitamin D can significantly enhance testosterone production. If your vitamin D level is already optimal (>55nmol/l), increasing supplementation with it will not further boost testosterone.

Yacon Root

Yacon (aka Smallanthus sonchifolius) is a tuber vegetable commonly used in South America to extract a syrup. It is similar to a potato and has been shown to benefit gut health.

Yacon’s interaction with testosterone has only been researched in one rodent study:

• Rats given 200mg/kg of Yacon extract for 5 weeks had 3x higher testosterone levels compared to the control group (Source).

Now, although this is an astounding result we cannot say that the same effect will carry on to affect humans.

Due to a lack of human research, Yacon root is only a potential testosterone boosting ingredient.

(source)

Zinc

Zinc is an essential trace mineral in the human body that regulates enzymes and provides immunity and antioxidant benefits. This is another mineral that is widely cited as a testosterone booster:

a) Elite wrestlers supplementing with 3mg of zinc/kg per day were able to prevent sharp drops in testosterone that occurred after exhaustion (89).

b) In male patients on hemodialysis with zinc deficiencies, 250mg of daily zinc supplementation for 6-weeks increased testosterone levels by 89.6% (90).

c) Male subjects put on an exercise bicycle experienced a sharp drop in testosterone. Supplementing with 3mg of zinc/kg prevented this sharp drop (91).

d) Infertile men supplementing with zinc experienced significant increases in testosterone and DHT (92).

Key Takeaway

A deficiency of zinc can significantly lower testosterone. If you’re already getting sufficient amounts of zinc through diet, supplementation is not likely to further enhance your testosterone.