- Clinically dosed ingredients
- Can help increase muscle strength
- Accelerates muscle growth and fat reduction
- 10 research-backed ingredients
- Transparent dosage labeling
- 90-day money-back guarantee
Written by Steve Theunissen | ISSA: CPT & Fitness Nutrition
Fact checked by Robert Iafelice, MS, RD, LDN
FACT CHECKED
Methodology
We adhere to a strict methodology when reviewing products. We strive to deliver you an unbiased opinion on products and services so that you're able to make an informed decision. Learn More
We adhere to a strict methodology when reviewing products. We strive to deliver you an unbiased opinion on products and services so that you're able to make an informed decision. Learn More
It's easy to get confused between testosterone-boosting supplements. Not only do they often contain similar ingredients, but many of them also have very similar-sounding names. Case in point - TestoPrime and TestoFuel. They're both popular natural testosterone boosters with names that are easy to mix up. Yet, they are very different products.
In this comparison article, we clear up the confusion between these two testosterone boosters by putting them head to head. We'll compare them in terms of ingredients, dosage, effectiveness, and side effects. By the end of this article, you'll have a much clear understanding of the differences between TestoPrime and TestoFuel and which one is best suited for your goals.
** This post may contain affiliate links where we make a small commission on purchases made at no cost to you. We only recommend products we think you will find valuable.**
TestoPrime Vs TestoFuel: Which test booster is better?
Both TestoPrime and TestoFuel are effective natural testosterone boosters. Yet they have different areas of focus. Increasing testosterone levels may result in a stronger performance in the gym, as evidenced by increased strength levels and boosted protein synthesis for muscle growth post-workout. Another potential outcome is increased virility and performance in the bedroom. A third benefit is increased long-term hormonal improvements that offset the natural age-related testosterone decline.
Based on a combination of personal experience, ingredients, and dosage analysis (which we'll get into shortly) and verified user comments, we believe that TestoFuel is a better choice for people who are focused on improving their workout results. I personally noticed a greater strength increase when I was taking TestoFuel for four weeks than when I switched to TestoPrime for the same length of time. User reviews confirm my observations.
When it comes to boosting virility and sexual performance, TestoPrime seems to have the upper hand. That's not to say that it won't help you in the gym. You should still notice a surge in strength when you take this supplement regularly. However, the combination of ingredients will also do a better job of enhancing your libido than those in TestoFuel.
Both products seem to perform equally well when it comes to helping reverse age-related testosterone deficiency.
You'll notice from our ingredient and dosage breakdowns that TestoFuel is dosed in higher amounts than TestoPrime. For example, there are four times more fenugreek and two and a half times more ginseng in each serving of TestoFuel. So, it's fair to say that TestoFuel is the more potent product.
What is TestoPrime?
TestoPrime is a natural testosterone booster manufactured by UK company Wolfson Brands. The key ingredient in this supplement is D-Aspartic Acid, which is claimed to be able to increase testosterone production by up to 42%. One thing I noticed on the official TestoPrime website is that they make very specific claims about their product. Some of them are:
- Reduce stress by up to 71.6%
- Burn overall body fat by up to 16%
- Increase muscle strength by up to 138.7%
- Improve endurance by 92.2%
- Improve fat conversion by up to 12%
This product is also meant to improve concentration, sleep, and libido.
TestoPrime is only available from the official website. It is manufactured in both the US and the UK in FDA-registered and CMP-certified factories. Last but not least, TestoPrime comes with a lifetime guarantee!
There are a lot of reviews for TestoPrime online. On Reddit, there are a number of spirited discussions about the product's benefits. Here is a typical experience, as related by Reddit user u/Big-Mike-1:
"I've been taking Testoprime for about 3 weeks now. My normal routine is to weight lift and play basketball or tennis for cardio. I was in above average shape going into taking this, but never anything too special, but after taking this for 3 weeks now giving it time to kick in properly, I have noticed significant changes. I haven't been on the same strict routine the last week and I've eaten a lot unhealthier than normal yet I'm more fit than I've ever been, I have so much more energy, and for me especially I don't feel as stressed out and irritated all the time I feel more level headed. I don't grow much facial hair but it's also seemed to be growing more now. I would definitely recommend it, it's seem to be working incredibly well for me."
TestoPrime is an all-natural testosterone support that can help any man take control of his youthful vitality with a flood of new and natural testosterone...
What is TestoFuel?
TestoFuel is another all-natural testosterone booster. It is more specifically marketed as a muscle-building supplement than TestoPrime. TestoFuel is a product from the popular UK gym supplement company Roar Ambition. Other popular products in their range include Instant Knockout Fat Burner and 4-Gauge pre-workout.
TestoFuel is primarily designed to increase muscle mass and strength by encouraging the body to produce more testosterone. It also claims to be able to reduce fat and boost self-confidence.
Reddit user u/Ea127586 has been using TestoFuel instead of TRT. Here's his experience:
"I just remember my GP saying "Whoa your T levels are surprisingly low".
Take heed here though. He advised against TRT, because it can cause a permanent change in your body chemistry and he recommended I take a natural supplement instead, and if that didn't work we'd try the more extreme approach of testosterone replacement therapy. I use TestoFuel and swear by it, it got my numbers up and I feel like myself again, without any risk to altering my thyroids natural ability to make hormones."
TestoFuel is considered to be a revolutionary, exhaustively researched muscle building supplement with one very focused aim...to smash down the barriers to growth by opening your testosterone floodgates...
12 TestoPrime Ingredients
A supplement is only as good as its ingredients. Here's an overview of the dozen ingredients in TestoPrime and why they've been included.
1. D-Aspartic Acid - 2000mg
D-Aspartic acid is an amino acid that has been shown to help boost testosterone levels. It does so by stimulating the body's release of luteinizing hormone (LH). This then enhances testosterone production. So it's no wonder why this is one of the most common ingredients seen in testosterone boosting supplements.
In a 2009 study, researchers investigated how D-aspartic acid influenced the release of LH and testosterone in both human and rodent subjects. Previous studies were reviewed, and then the researchers conducted their own experiments. They found that both LH and testosterone increased as a result of D-aspartic acid supplementation. In men, the increase of testosterone production in the tests was as high as 42%.¹
2. Panax Ginseng - 40mg
The herb Panax ginseng, commonly called Asian ginseng, has been used for thousands of years in traditional Chinese medicine to support general health and wellness. One of Panax ginseng's many advantages is that it might help increase men's testosterone levels.
Although the exact method by which Panax ginseng raises testosterone levels is unknown, research has found several likely methods. One of the hypothesized theories is that it increases luteinizing hormone (LH), which is released by the pituitary gland. Higher levels of LH can result in increased amounts of testosterone because LH is the hormone that instructs the testes to produce the hormone.² Ginseng is one of many traditional medicines that has seen a resurgence in being a staple of natural performance enhancing supplements.
3. KSM®-66 Ashwagandha Extract - 55.68mg
The adaptogenic herb ashwagandha has been used in Ayurvedic medicine for centuries. It has been demonstrated that the ashwagandha extract KSM-66 may raise testosterone levels in males. According to research, taking KSM-66 as a supplement can raise testosterone levels by up to 17%.³ Ashwagandha supplements have seen a remarkable increase in use over the past decade.
4. Fenugreek - 200mg
Fenugreek is a herb that may boost testosterone production by inhibiting aromatase, which converts testosterone into estrogen. Researchers also believe that it may stimulate LH secretion in the pituitary gland, which then promotes testosterone production in the testes. A third way that fenugreek may boost 'T' levels is by improving insulin sensitivity and reducing inflammation. Both of these things can have a positive effect on testosterone levels.⁴ Fenugreek has been used for years as a natural way to combat erectile dysfunction.
5. Green Tea Extract - 200mg
Although there are a number of probable pathways, the exact method by which green tea extract raises testosterone levels is not entirely understood. One theory is that green tea extract may inhibit the enzymes that transform testosterone into estrogen, similar to fenugreek.
Green tea extract may also help promote the release of luteinizing hormone (LH) from the pituitary gland, which in turn helps stimulate the creation of testosterone in the testes.
The antioxidants abundant in green tea extract also help prevent oxidative inflammation and stress in the body. This may have a favorable effect on general health, including testosterone production.⁵
6. Pomegranate Extract - 8mg
In addition to inhibiting certain enzymes that convert testosterone into estrogen, pomegranate extract may boost the body's production of nitric oxide (NO). NO is a vasodilator that increases blood vessel size, allowing more blood and nutrients to pass through. The enhanced blood flow that results brings more oxygen to the testes. This may help boost testosterone production.⁶
7. Vitamin D - 26.68mcg
Low levels of vitamin D in men have been associated with reduced testosterone production. Researchers believe that this may be due to vitamin D's ability to stimulate LH production. Vitamin D is also important for bone health, immune function, and reducing inflammation.⁷ All the aforementioned benefits is one of the reasons why Vitamin D supplements are some of the most widely taken.
8. Zinc - 40mg
Zinc is a necessary mineral for good health and well-being, and is vital for maintaining normal testosterone levels. According to research, testosterone levels may drop due to zinc insufficiency, which may have an effect on libido, energy, and muscle growth.
Zinc has been found to improve male fertility since it affects sperm production and quality. It also contains immune-boosting qualities and can improve overall immunological function, which is crucial for athletes who could be more vulnerable to disease and infection because of their demanding training schedules.
Zinc is also important for protein synthesis, which is a key process for muscle growth and recovery. It also plays a role in energy metabolism and can help to improve overall energy levels and reduce fatigue.
The zinc in TestoPrime is in the form of zinc citrate, which is an easily absorbable form of the mineral.⁸
9. Vitamin B6 - 5.6mg
Vitamin B6 is an essential vitamin that is needed for general health and well-being. B6 is involved in protein metabolism and has been demonstrated to have a positive impact on testosterone levels. Studies show that it may help to regulate prolactin levels. Prolactin is a hormone that inhibits testosterone production in the testes. Vitamin B is one of the most important vitamins when it comes to muscle growth.
Vitamin B6 is also important for the production of energy.⁹
10. Vitamin B5 - 8mg
Vitamin B5, also known as pantothenic acid, plays a key role in the body's numerous metabolic activities, including the manufacture of hormones, neurotransmitters, and energy. Studies have demonstrated that vitamin B5 has a beneficial effect on the body's capacity to handle stress. B5 stimulates the release of adrenal hormones, and these hormones help control how the body reacts to stress. Vitamin B5 can help minimize the adverse effects of stress on the body, such as exhaustion and burnout, by promoting healthy adrenal function.
Vitamin B5 is also important for energy metabolism.¹⁰
11. Garlic Extract - 16mg
Allicin, one of the compounds in garlic, has been shown to have a positive effect on testosterone levels. It does this by raising the body's luteinizing hormone (LH) levels. Garlic extract is also known to offer a number of other health benefits which is why garlic supplements are a staple of many people's diet. It possesses anti-inflammatory and antioxidant characteristics that may help to lessen oxidative stress and inflammation in the body.¹¹
12. Black Pepper Extract - 6.68mg
Black pepper extract, or piperine, has been shown to improve the bioavailability and absorption of other ingredients in the supplement. Many nutrients, such as vitamins, minerals, and other plant compounds, have been proven to be better absorbed when piperine is added.¹²
10 TestoFuel Ingredients
Five of the ten ingredients in TestoFuel are also in TestoPrime. In this overview of TestoPrime ingredients, we focus on those that differ. For those in common, we'll just provide the dosage.
1. D-Aspartic Acid - 2000mg
Equal dosage to TestoPrime.
2. Maca Root Extract - 1800mg
Peruvian natives have been using the medicinal benefits of maca root for millennia, and now everyone can take advantage with the large selection of maca root supplements available. Macamides, one of the substances in maca root, are thought to have a positive effect on testosterone levels by enhancing the body's luteinizing hormone (LH) production.
Maca root extract is known to have numerous health advantages besides its potential effect on testosterone levels. It has been shown to possess antioxidant and anti-inflammatory effects, which may help the body to reduce oxidative stress and inflammation.¹³
3. Asian Red Panax Ginseng Extract - 100mg
Each serving of TestoFuel provides two and a half times as much Panax ginseng as you get in TestoPrime.
4. Oyster Extract - 100mg
Oyster extract is a great source of some compounds that are vital for healthy testosterone production and general well-being. Zinc, magnesium, and vitamin D are all known to be abundant in oysters and are all crucial for preserving healthy testosterone levels.¹⁴
5. Fenugreek Seed Extract - 800mg
This is four times the amount you get with TestoPrime.
6. Boron - 8mg
Boron is a mineral that may help to boost testosterone production. A study found that men who took boron for a single week experienced a significant increase in their free testosterone level.¹⁵
7. Vitamin D3 - 100mcg
TestoFuel contains almost four times the amount of vitamin D3 per serving.
8. Vitamin K2 - 18mcg
Vitamin K2 is a fat-soluble vitamin that contributes to bone and heart health and also plays a vital role in blood clotting. Research suggests that K2 supplementation may also increase testosterone levels.¹⁶
9. Magnesium - 70mg
Magnesium is involved in a range of metabolic processes. Studies show that it may also boost testosterone synthesis, increasing both free and total 'T' levels in the body.¹⁷ Another benefit of magnesium supplementation is that it supports healthy sleep.
10. Zinc - 10mg
TestoPrime does beat out TestoFuel here by 30mg.
Benefits of TestoPrime
Now that we've broken down the ingredients of both products, we are in a good position to evaluate the claimed benefits of each. Let's start with TestoPrime.
1. Reduces Stress
Stress has been shown to have a direct correlation to fat gain. By inhibiting cortisol levels, TestoPrime may be able to speed up fat burning. Ashwagandha is an ingredient that has been shown to have cortisol-inhibiting properties. It is also known as an adaptogenic, helping the body better adapt to stressful conditions.
2. Helps burn overall body fat
Wolfson Brands claim that the synergistic combination of ingredients in TestoPrime will boost overall fat-burning capacity by 16%. This is achieved through increased testosterone levels and the fat-burning ability of such ingredients as vitamin B6 and green tea extract. Ashwangandha's stress-reducing properties also help with weight control.
3. Increases muscle strength
According to the company, TestoPrime can increase muscle strength by up to 137%. On the official website, the claim is made that the product's ability to boost blood flow is the main driver of muscle strength increase. That's a bit of a head-scratcher; it's more likely to be the increased testosterone production and improved protein synthesis that comes from ingredients such as D-aspartic acid, magnesium, and fenugreek.
4. May improve endurance
Some of the ingredients in TestoPrime may increase endurance levels. These include Ashwagandha extract, which lowers stress levels. Reduced cortisol has been associated with improved levels of energy and endurance. Vitamin B6 is another ingredient that may increase endurance levels due to the role it plays in energy metabolism.
5. May help convert fat into energy
By promoting enhanced metabolic activity and energy generation, several of the ingredients in TestoPrime helps to convert fat into energy. The same two ingredients that are involved in energy production – Vitamin B6 and Ashwagandha – stand out here.
Carbohydrates, lipids, and proteins can all be converted into energy with the assistance of vitamin B6. As a result, vitamin B6 may indirectly encourage the conversion of excess body fat to energy by supporting a healthy metabolic process.
Ashwagandha extract may indirectly help in the conversion of fat to energy. In addition to having adaptogenic qualities, ashwagandha can also help with stress reduction.
TestoPrime is an all-natural testosterone support that can help any man take control of his youthful vitality with a flood of new and natural testosterone...
TestoPrime Side Effects
So long as you take it as directed, TestoPrime is a safe supplement. It contains only natural ingredients and is free of any preservatives, fillers, or flavorings. There have been no reported major side effects in any of the studies done on TestoPrtime ingredients or through customer feedback.
As with all supplements, however, there are some minor side effects that might be experienced by some users. These include acne, stomach discomfort, gas, and bloating.
Benefits of TestoFuel
Let's now turn to the claimed benefits that Roar Ambition makes regarding TestoFuel.
1. Increase lean muscle mass
D-aspartic acid, vitamin D, and zinc are a few naturally occurring ingredients of TestoFuel that have been proven to raise the body's testosterone levels. The process through which the body creates muscle tissue from amino acids is known as protein synthesis, and TestoFuel can assist in increasing it by raising testosterone levels. By encouraging the release of growth hormone, testosterone also contributes to the growth of lean muscle mass.
TestoFuel not only promotes muscle growth but also has the potential to lessen muscle wasting. Since testosterone has been demonstrated to have anti-catabolic properties, supplementing with TestoFuel may be able to lessen the likelihood of muscle loss. This can help bodybuilders and athletes in preserving muscle mass during periods of hard training and prevent muscle loss during layoffs.
2. Increase strength
TestoFuel increases your body's testosterone levels, which will make you stronger. Testosterone is essential for building strength since it controls the synthesis of red blood cells, bone density, and muscular growth.
TestoFuel can help increase muscle strength by promoting muscle growth, quickening the recuperation of tired muscles, and improving bone density by increasing testosterone levels. I have personally experienced a significant increase in strength in such exercises as the dumbbell bench press, cable curl, and shoulder press after taking TestoFuel for a month.
3. Helps reduce body fat
TestoFuel helps improve metabolic rate, boost fat burning, and reduce body fat by raising testosterone levels.¹⁸
According to studies, testosterone increases the activity of the lipolysis enzymes, which burn stored fat for energy, hence promoting fat loss. Lean muscle tissue, which testosterone also encourages to grow, can assist in boosting metabolic rate and aid in burning more calories throughout the course of the day.
4. Improved mood
D-Aspartic Acid, Vitamin D, and Ginseng are a few naturally occurring ingredients that raise testosterone levels and elevate mood. Increased testosterone levels help people feel happier, less stressed out and anxious, and perform better in their cognitive tasks.
Testofuel not only increases testosterone levels but also has the potential to lessen oxidative stress and inflammation, two things that might contribute to mood disorders like anxiety and sadness. Some of the ingredients in TestoFuel contain antioxidant and anti-inflammatory qualities that can help safeguard the brain and enhance general mental health.
5. Increased confidence
The claim of increased confidence is based on TestoFuel's ability to increase testosterone levels. Higher testosterone levels are associated with increased confidence, greater assertiveness, and boosted self-esteem.
TestoFuel is considered to be a revolutionary, exhaustively researched muscle building supplement with one very focused aim...to smash down the barriers to growth by opening your testosterone floodgates...
Testofuel Side Effects
TestoFuel is a completely natural supplement that is free of preservatives, additives, and any other unnatural ingredients. There are no reported major side effects that have been reported regarding this product or any of its constituent ingredients. However, some reviewers have reported such minor side effects as headaches, nausea, stomach upset, and gas.
When should I take them: TestoPrime vs Testofuel?
The recommended dosage for TestoPrime is four capsules per day, ideally taken with breakfast. To ensure the best outcomes, take TestoPrime consistently at the same time every day.
Four capsules per day is also the recommended dosage for TestoFuel. The supplement should be taken with a meal. TestoFuel should also be taken at the same time every day.
It's important to remember that neither supplement should be taken in excess of the manufacturer's recommended dosage.
How to take them: TestoPrime vs Testofuel?
Both TestoPrime and TestoFuel should be taken with food. The manufacturer of TestoPrime recommends taking the supplement with breakfast, while there is no specific meal recommendation with TestoFuel.
How much do they cost: TestoPrime vs Testofuel?
A one-month supply of TestoPrime costs $64.99.
A three-month supply is $129.99, saving you $21.66 per month.
A five-month supply is $194.99, saving you $25.99 per bottle.
All orders include free shipping.
A one-month supply of TestoFuel costs $65.00.
A two-month supply is $130.00.
A four-month supply is $195.00, saving you $26.00 per bottle.
All orders include free shipping.
From the above, we can see that the pricing is virtually identical between the two products.
TestoPrime vs TestoFuel FAQs
Does TestoPrime make you stronger?
TestoPrime increases testosterone levels. Doing so may help you become stronger because testosterone is essential for muscular development, strength, and general athletic performance.
But TestoPrime is not a magic pill that will instantaneously make you stronger. Instead, TestoPrime supports normal testosterone levels, which, when combined with a good diet and workout program, can indirectly result in more muscle growth and strength.
Does TestoFuel make you stronger?
TestoFuel may also make you stronger as a result of increased testosterone levels. I have personally experienced strength gains in the gym from taking TestoFuel to a greater extent than TestoPrime.
How long does TestoPrime take to work?
TestoPrime may take longer or shorter to start working, depending on your age, health, nutrition, and lifestyle choices. According to the official website, the ingredients begin to work rapidly so that users may begin to experience benefits within the first two to three weeks of consistent use. TestoPrime's full effects, however, might not be felt for up to two or three months because the body needs time to react and raise its levels of natural testosterone. Also, remember that TestoPrime comes with a lifetime guarantee in case you're not satisfied.
How long does TestoFuel take to work?
As with TestoPrime, the time it takes for TestoFuel to start working may also be affected by a person's workout habits, diet, age, and level of health. It will also take a bit of time for the body's testosterone levels to increase.
Based on my personal experience, I can say that I felt the effects in terms of strength and muscle increase faster with TestoFuel than TestoPrime. Those effects were felt after 3-4 weeks.
Summary
While other testosterone boosters claim to be effective, both TestoPrime and TestoFuel are high-quality, top-selling natural testosterone boosters. They both cost roughly the same and include many of the same ingredients. It's the unique ingredients, like maca root extract, oyster extract, and green tea extract, that set them apart. In general, TestoFuel is dosed at higher levels than TestoPrime.
If you're after a testosterone booster that will ramp up your strength levels in the gym and boost your muscle-building potential, then TestoFuel is the product for you. For those of you who want a more general-purpose supplement that boosts libido, increases energy, and combats fatigue, then you should opt for TestoPrime.
References:
- Topo, E., Soricelli, A., D'Aniello, A. et al. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reprod Biol Endocrinol 7, 120 (2009).
- Park, S. H., Yoon, J. S., Won, J. H., Lee, J. H., & Kim, K. T. (2014). Effects of Panax ginseng extract on male hormones and reproductive activity in healthy male volunteers: a randomized, double-blind, placebo-controlled clinical trial. Journal of Ginseng Research, 38(2), 106-111. doi: 10.1016/j.jgr.2013.11.005.
- Ambiye, V. R., Langade, D., Dongre, S., Aptikar, P., Kulkarni, M., & Dongre, A. (2013). Clinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males: A Pilot Study. Evidence-based complementary and alternative medicine : eCAM, 2013, 571420. doi:10.1155/2013/571420.
- Steels, E., Rao, A., Vitetta, L. (2011). Physiological Aspects of Male Libido Enhanced by Standardized Trigonella foenum-graecum Extract and Mineral Formulation. Phytotherapy Research, 25(9), 1294-1300. doi: 10.1002/ptr.3360.
- Hsu, C. H., Tsai, T. H., Kao, Y. H., Hwang, K. C., Tseng, T. Y., & Chou, P. (2003). Effect of green tea extract on testosterone and lipid peroxidation in rats exposed to restraint stress. Acta Pharmacologica Sinica, 24(10), 1292-1296. doi: 10.1038/sj/aps/1003329.
- Mirmiranpour, H., Khaghani, S., & Zandieh, Z. (2012). Effects of pomegranate extract supplementation on testosterone levels of endurance-trained males after an acute bout of exercise. Polish Journal of Food and Nutrition Sciences, 62(3), 171-175. doi: 10.2478/v10222-011-0043-3.
- Pilz, S., Frisch, S., Koertke, H., Kuhn, J., Dreier, J., Obermayer-Pietsch, B., & Zittermann, A. (2011). Effect of Vitamin D Supplementation on Testosterone Levels in Men. Hormone and Metabolic Research, 43(3), 223-225. doi: 10.1055/s-0030-1269854.
- Prasad AS, Mantzoros CS, Beck FW, Hess JW, Brewer GJ. Zinc status and serum testosterone levels of healthy adults. J Nutr. 2009; 135(2): 279-283. doi: 10.1093/jn/135.2.279. PMID: 19141660.
- Dakshinamurti S, Dakshinamurti K. Vitamin B6. In: Stipanuk MH, ed. Biochemical and Physiological Aspects of Human Nutrition. Philadelphia, PA: Saunders Elsevier; 2013: 422-438.
- Takahashi K, Akiba Y, Ohtani M, et al. Effect of vitamin B6 and pantothenic acid on fatigue and endurance capacity in rats. J Nutr Sci Vitaminol (Tokyo). 2008; 54(6): 491-496. doi: 10.3177/jnsv.54.491.
- Morales-Peza N, Flores-Fernandez JM, De la Cruz-Mosso U, et al. Effect of oral garlic administration on serum testosterone levels in adult men: a meta-analysis of randomized controlled trials. Phytother Res. 2021; 35(1): 141-149. doi: 10.1002/ptr.6799.
- Shoba G, Joy D, Joseph T, et al. Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers. Planta Med. 1998; 64(4): 353-356. doi: 10.1055/s-2006-957450.
- Gonzales GF, Cordova A, Vega K, et al. Effect of Lepidium meyenii (Maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men. J Endocrinol. 2003; 176(1): 163-168. doi: 10.1677/joe.0.1760163.
- Yalcin S, Gumus M, Yuce A, et al. Effects of oyster extract on the reproductive functions of male rats. Bratisl Lek Listy. 2015; 116(3): 156-160. doi: 10.4149/bll_2015_030.
- Naghii MR, Mofid M, Asgari AR, et al. Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. J Trace Elem Med Biol. 2011; 25(1): 54-58. doi: 10.1016/j.jtemb.2010.10.001.
- Nimptsch K, Rohrmann S, Nieters A, et al. Serum undercarboxylated osteocalcin as biomarker of vitamin K intake and risk of prostate cancer: a nested case-control study in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. Cancer Epidemiol Biomarkers Prev. 2009; 18(1): 49-56. doi: 10.1158/1055-9965.EPI-08-0555.
- Cinar V, Polat Y, Baltaci AK, et al. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biol Trace Elem Res. 2011; 140(1): 18-23. doi: 10.1007/s12011-010-8676-3.
- Willoughby DS, et al. Effects of 28 days of resistance exercise and consuming a commercially available pre-workout supplement, NO-Shotgun(R), on body composition, muscle strength and mass, markers of satellite cell activation, and clinical safety markers in males. J Int Soc Sports Nutr. 2012;9(1):1-19. doi:10.1186/1550-2783-9-1.
Steve Theunissen
Author