As an important amino acid, D-AA is responsible for not only regulating testosterone synthesis, but growth hormone production and muscle mass too.

It plays a key role in boosting the parts of the brain that regulate hormone release, especially luteinizing hormone – a T pre-cursor released from your pituitary gland that essentially tells your testes to make more T.

One study found that when a group of men supplemented D-AA for as little as 90 days, T levels rose by an average of 30-60%[1]. Not only that, but sperm count went up by 60-100% too.

1. D’Aniello, S et al. D-aspartate, a key element for the improvement of sperm quality. Adv. Sex. Med. 2012; 2: 47–53

This nutrient is often referred to as the sixth steroid hormone because of its ability to support your male hormones. It’s a nutrient that’s produced in the body when it comes into contact with UV rays from the sun – the problem is though that particularly in the west, we just don’t get enough of it, so a supplement is a must!

Numerous, exhaustively researched clinical trials have shown that vitamin D can kick-start testosterone levels. One of these studies found that 3,332 IUs of the vitamin boosted testosterone to significantly higher values[2].

Another study, published in the Journal of Science and Medicine in Sport[3], found that doses of 4,000 IU and above helped a group of athletes increase strength and muscle mass - all with absolutely no side effects.

Not only that, higher doses of vitamin D can also reduce muscle soreness[4], improve cognitive performance[5] and maximal endurance too[6].

We chose to put vitamin D in TestoFuel because there seriously isn’t a better natural stimulator of testosterone. Period.

2. Pilz, S et al. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011;43(3):223–225

3. Tomlinson, PB et al. Effects of vitamin D supplementation on upper and lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis. J Sci Med Sport. 2015 Sep;18(5):575-80.

4. Barker, T et al. Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise. Nutr Metab (Lond) 2013; 10: 69

5. Kenny, AM et al. Effects of vitamin D supplementation on strength, physical function, and health perception in older, community-dwelling men. J Am Geriatr Soc. 2003; 51(12): 1762-7

6. Jastrzebski, Z. Effect of vitamin D supplementation on the level of physical fitness and blood parameters of rowers during the 8-week high intensity training. Facicula Educ Fiz si Sport. 2014; 2:57-67

What’s the first food you think of when you’re wanting to boost your libido? Oysters of course.

And you wouldn’t be wrong to think that ether, as it’s a well-known aphrodisiac food. Research shows a clear link between this zinc-rich food and its ability to elevate testosterone.

In fact, oysters are the best source of zinc you’ll find – around 10 times the amount you’ll find in beef steak. And it’s the zinc that’s the key ingredient in this food, because prostate tissue requires more zinc than any other cells in the body.

Numerous studies have found that oyster extract improves reproductive function, keeps testosterone receptors firing on all cylinders, and also inhibits aromatization – the process by which some of your testosterone converts to estrogen[7]. This means more masculinity, less belly fat and the dreaded man boobs.

7. Matsuda, Y et al. Effects of oyster extract on the reproductive function of zinc-deficient mice: bioavailablity of zinc contained in oyster extract. Congenit Anom. 2003; 43(4): 271-9

This Asian herb has been shown to improve mood and cognitive ability – it’ll keep your immune system strong to.

Originally used as a libido enhancer and aphrodisiac, ginseng has recently been found to directly influence testosterone levels too. One study found that short-term use of the herb, increased both testosterone and its potent derivative DHT[8]. On top of that, it increases the release of luteinizing hormone (LH) and adrenocorticotropic hormone (ACTH), both of which help to stimulate testosterone release.

The benefits don’t end there either though. Because ginseng also has the ability to boost muscle pumps by elevating levels of nitric acid in your blood, and helps to improve insulin sensitivity[9], which can help you shred body fat and stay lean.

8. Salvati, G et al. Effects of panax ginseng C.A. Meyer saponins on male fertility. Panminerva Med. 1996; 38(4): 249-54

9. Pitteloud, N et al. Relationship between testosterone levels, insulin sensitivity and mitochondrial function in men. Diabetes Care. 2005; 28(7): 1636-1642

Fenugreek is a herb you’d find in Mediterranean climates. Much like ginseng, it’s commonly used in Asian cuisine and has a sweet and distinctive aroma.

Packed full of zinc, magnesium and selenium, fenugreek has the ability to slam the brakes on sex hormone binding globulin (SHBG). This protein is responsible for swallowing up testosterone in your blood stream so if it’s inhibited, your ‘free’ testosterone can do it job much more effectively.

Studies show that even with modest amounts of the herb, both total and free hormone levels are significantly ramped up[10].

10. Wilborn, C et al. Effects of a purported aromatase and 5α-reductase inhibitor on hormone profiles in college-age men. Int J Sport Nutr Exerc Metab. 2010; 20(6):457-65

This essential mineral works as a co-factor in the human body. This means that it regulates hundreds of enzymatic reactions including those that regulate the brain, bones and heart.

It supports physical endurance and metabolism as well as helps regulate the amount of strength and force your muscles can generate.

It also promotes recovery from intense workouts, boosts sleep quality and improves lean mass. Everything you’ll need for those big, tough gym sessions.

Of course, we’ve used it in TestoFuel because not only does it do all of the above; it’s been found to significantly elevates testosterone levels too, even in short-term human studies[11].

If you hit the gym on a regular basis, chances are you’re not getting enough magnesium in your diet. Current research suggests that many athletes only get around 70% of the amount they need; and some get less than 60%[12].

11. Cinar, V. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biol Trace Elem Res. 2011; 140: 18–23

12. Nica, AS et al. Magnesium supplementation in top athletes – effects and recommendations. Med Sport. 2015; XI(1): 2482-2494

Known as menaquinone in the research, vitamin K2 is the silent hero of TestoFuel.

You’ll find this nutrient in foods such as red meat and egg yolks and liver – all good anabolic hormone-boosting foods. The problem is though that these foods are also quite high in fat so might not support your fat-stripping goals that well. The solution? Supplement it instead.

Studies have shown that K2 compliments vitamin D3, allowing them to tag team your testes into submission, resulting in more testosterone release[15].

Not only does this vitamin play a supportive role in ramping up hormone release, it does it directly too. One study found that supplementing K2 for as little as 5 weeks led to a 70% increase in circulating testosterone levels[16].

15. Ushiroyama, T et al. Effect of continuous combined therapy with vitamin K2 and vitamin D3 on bone mineral density and coagulofibrinolysis function in postmenopausal women. Maturitas. 2002; 41; 211-221

16. Ito, A et al. Menaquinone-4 enhances testosterone production in rats and testis-derived tumor cells. Lipids Health Dis. 2011; 10: 158

It’s zinc to make the girls wink with this nutrient as supplementing it in your diet is a sure-fire way of ramping up those T levels.

As an essential mineral, zinc has the power to boost luteinizing hormone levels – an important brain hormone that tells your testes to spurt out some testosterone into your bloodstream.

Current research shows that a diet low in zinc spells disaster to testosterone levels as a deficiency in the mineral causes androgen receptors to become inefficient[17].

And unsurprisingly, adding zinc to the diet has been found to directly boost T levels as well as massively decrease aromatization – the process by where testosterone rapidly converts to the female hormone estrogen[18].

17. Prasad, AS et al. Zinc status and serum testosterone levels of healthy adults. Nutrition. 1996; 12(5): 344-8

18. Netter, A et al. Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count. Arch Androl. 1981; 7(1): 69-73

Boron is a natural element vital to human life. It occurs naturally in a number of varieties of green vegetables. Crucially, the latest scientific research suggests that boron plays an important role in helping your body produce testosterone (19).

But if your diet is sadly lacking in the fruits and vegetables containing boron, does this mean missing out on your own natural T-boost? Worry no longer, as TestoFuel contains 8mg of boron in every daily dose. This amount was found to increase free testosterone levels by approximately 25% in a landmark 2015 study(20).

Even better, boron supplementation has been shown to boost the effectiveness of Vitamin D - a key ingredient in Testofuel - which, in turn, is a brilliant natural stimulator of testosterone (21).

Boron is often the missing link in natural testosterone boosting. Don’t miss out for one minute longer; choose TestoFuel today.

19) Naghii, M. R. (1999). The significance of dietary boron, with particular reference to athletes. Nutrition and Health, 13(1), 31-37.

20) Pizzorno L. (2015). Nothing boring about boron. ncbi.nlm.nih.gov/pmc/articles/PMC4712861/

21) Pilz, S et al. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011;43(21):223–225

Once a sacred herb that Inca warriors considered essential, maca’s enormous impact is now being embraced by the West.

TestoFuel contains a generous dose of maca because of its phenomenal pre and post-workout properties. Groundbreaking 21st-century research proved that maca increased stamina and endurance - making it the perfect supplement to take before hitting the gym (22).

Maca has also demonstrated its ability to improve mood and feelings of wellbeing. Increasing your relaxed state can dramatically improve sleep quality - which in itself can have a considerable positive benefit on testosterone levels (23). And as an additional benefit, maca’s reputation as a natural libido raiser is well documented via studies throughout the globe.

When you consider all the positives maca delivers, the only question to ask is ‘Why would any test booster NOT contain this magical ingredient?’

22) Stone, M., Ibarra, A., Roller, M., Zangara, A., & Stevenson, E. (2009). A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen. Journal of ethnopharmacology, 126(3), 574-576.

23) Andersen, M. L., Alvarenga, T. F., Mazaro-Costa, R., Hachul, H. C., & Tufik, S. (2011). The association of testosterone, sleep, and sexual function in men and women. Brain research, 1416, 80-104.