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Nugenix Free Testosterone Booster Review: A Dietitian’s Objective Analysis

Written by Sharon Lehman, RDN

Reviewed by Anthony Dugarte, MD 

Last Updated on April 13, 2021

Dietitian Rating:


About This Rating
The average rating of this product is calculated based on the evaluation of the following factors:
  • Support for Claims:3.0
  • Ingredient Safety:4.0
  • Value for the Price:2.0
  • Brand Transparency:3.0

Nugenix Free Testosterone Booster is a men’s dietary supplement designed to support healthy levels of free testosterone for increased libido, enhanced muscle mass, and more stamina. There is limited evidence to support these claims.

Nugenix Free Testosterone Booster Review: A Dietitian’s Objective Analysis
Photo by WellnessVerge


  • Accessible at most major retailers
  • 30-day return policy
  • Relatively safe ingredients


  • Expensive
  • Lacks independent third-party testing
  • Amount of each ingredient in testosterone complex not specified


Nugenix Free Testosterone Booster contains a testosterone boosting ingredient complex designed to support healthy testosterone levels.

Testosterone boosting supplements, including Nugenix, claim that by bringing levels up, men will build more muscle with strength training, have increased strength, and enhanced sexual libido and performance.

Testosterone is the primary male reproductive hormone and has many functions in the body, including sexual function, reproduction, skin health, energy, mood, and brain health.

It also plays a role in body composition, helping to regulate fat metabolism and muscle mass.

Men naturally experience a decrease in testosterone levels as they age, usually beginning around the age of 30.

Low testosterone levels are linked to erectile dysfunction and an increased risk of serious diseases, like diabetes, heart disease, obesity, and depression.

Over-the-counter testosterone boosters have gained popularity since they’re considered safer than hormone replacement therapy.

The only way for a man to know if his testosterone levels are low is through blood work.

I feel that a lot of men reach for these “natural” testosterone supplements to enhance results in the gym and bedroom without lab work.

Evaluation of Ingredients

The product description on the Nugenix website states their Free Testosterone Booster contains eight ingredients that “have been lab tested for maximum effectiveness.”

Interestingly enough, I count only see six ingredients on the supplement facts label.

The only way this product contains eight ingredients is if they’re counting the two inactive ingredients: gelatin and magnesium stearate which are simply capsule ingredients.

This inaccuracy didn’t give me a great feeling about the product claims, but let’s see what the evidence says.

Nugenix ingredients label. Photo by WellnessVerge
Nugenix ingredients label. Photo by WellnessVerge

Vitamin B6 (pyridoxine hydrochloride)

Nugenix Free Testosterone Booster contains 2 milligrams of vitamin B6 per serving.

The Recommended Dietary Allowance for B6 is 1.3 milligrams per day and the Upper Limit is 100 milligrams per day.

Vitamin B6 plays a big role in energy production and protein metabolism.

Most people do not need B6 supplementation and get adequate amounts of B6 from food, where it’s found in poultry, pork, fish, white and sweet potatoes, and many fruits.

I couldn’t find too much information on a connection between vitamin B6 and testosterone, but several dated studies found lab animals with B6 deficiency had lower testosterone levels compared to animals given vitamin B6 supplementation.

Some research suggests that the need for vitamin B6 increases with exercise.

My guess is Nugenix includes B6 since it’s considered an “energizing” nutrient.

Vitamin B12 (methylcobalamin)

Nugenix Free Testosterone Booster contains 50 micrograms of vitamin B12 per serving.

The Recommended Dietary Allowance for B12 is 2.4 micrograms per day and no Upper Limit exists since toxicity is unlikely.

Most people get enough vitamin B12 from food, where it’s plentiful in animal foods, like meat, poultry, dish, eggs, and dairy.

Vegans and some vegetarians who don’t eat animal foods may require supplementation.

Vitamin B12 plays a role in cell production, including the creation of new red blood cells.

There is no link between vitamin B12 and testosterone production.

However, many energizing supplements include it to enhance energy and athletic performance even though there’s no evidence to support this if your levels are normal.

Zinc (zinc chelate)

Nugenix Free Testosterone Booster contains 1 milligram of zinc per serving.

The Recommended Dietary Allowance for zinc is 11 milligrams per day and the Upper Limit is 40 milligrams per day.

A review of research on zinc’s role in physical activity found that blood levels of zinc decreased following exercise, suggesting it plays a role in muscle recovery.

There’s also some evidence suggesting a relationship between levels of zinc and free testosterone in the body.

A small study conducted on male wrestlers found levels of free testosterone increased following 4 weeks of zinc supplementation.

Nugenix Free Testosterone Complex

The main ingredient in Nugenix Free Testosterone Booster is Nugenix Free Testosterone Complex, which contains L-citrulline malate, Testofen, and tribulus.

The label says each serving contains 2,103 milligrams of this complex but does not list the specific amounts of each ingredient.

L-citrulline malate

L-citrulline malate is an amino acid. In the body, it’s converted to another amino acid, L-arginine, which is involved in the production of nitric oxide.

Nitric oxide plays a role in healthy blood flow by dilating blood vessels.

Low levels of nitric oxide are linked to erectile dysfunction (ED).

Some evidence suggests L-citrulline supplementation can improve symptoms of mild ED in men.

Several studies have also looked at the effect of L-citrulline on exercise endurance and fatigue, but supplementation was not effective at improving performance for high-intensity plyometrics, upper-body resistance training, or cycling.


Testofen is a registered name for a brand of fenugreek seed extract. Fenugreek is a plant that’s used in cooking and ancient medicinal practices.

There is some evidence that fenugreek seed extract improves testosterone levels, libido, and body composition in men.

This double-blind, randomized controlled trial involving 120 men found men taking 600 milligrams of fenugreek seed extract per day for 12 weeks had improvements in sexual function and testosterone compared to the placebo group.

Another study involving 60 men found those who took 600 milligrams of Testofen per day had improved libido compared to the placebo group.

A study of 49 men found that those who took 500 milligrams of fenugreek seed extract for 8 weeks had enhanced body strength and improved body composition compared to those taking a placebo.


Tribulus also has a history of use in ancient medicine.

It’s often found in testosterone boosting supplements, even though research has mixed findings regarding its usefulness.

Several studies have found tribulus supplementation has no effect on testosterone levels or erectile dysfunction, but that it may improve libido.

There’s also no evidence to support its use by athletes for boosting performance or body composition.

Verdict on Claimed Benefits

Below is our summary of the available evidence for the claimed benefits of Nugenix Testosterone Booster based on the available research:

Increase sex driveModerate Evidence
Enhance muscle massModerate Evidence
Boost free testosteroneModerate Evidence

Side Effects, Safety, and Dosage

The recommended dosage for Nugenix Free Testosterone Booster is 3 capsules per day taken on an empty stomach.

The instructions advise taking the supplement in the morning or 30–45 minutes before a workout.

On the product FAQ page, the brand advises supplementing with Nugenix for 8 weeks in combination with exercise.

They also make a suggestion for men who feel like they need more testosterone booster than the recommended dosage.

The website says increasing the dosage from 3 capsules to 4 or 5 capsules is acceptable because it “will still be in a safe tolerance zone.”

I don’t agree with supplement companies basically giving users a free pass to increase the recommended dosage if they see fit.

How would someone know they’re not getting enough?

I’m wary of supplements that list a “complex” on the ingredient label but fail to provide the exact amount of each ingredient.

Although the ingredients in Nugenix Free Testosterone Booster are probably safe for most healthy men to take without any serious risk of adverse side effects, not knowing the exact amount of the active ingredient poses some problems.

Some may experience mild digestive upset while using this supplement.

This also contains a high amount of vitamin B12, which doesn’t pose any serious safety concerns but seems wasteful.

You could be getting an excessive amount if you’re taking other supplements, like a multivitamin or pre-workout, that also contain vitamin B12.

Nugenix doesn’t contain quite as much vitamin B6 or zinc, but you’ll want to check the amount of these in other supplements to make sure you’re not getting too much.

Although it’s unlikely this supplement will result in excessive testosterone, it’s a good idea to be aware of signs your testosterone levels may be too high.

Acne, voice changes, excessive body hair, male pattern baldness, and mood imbalances can result from too much testosterone.

If you notice any of these changes, check in with your primary healthcare provider ASAP. 

If you want to try this or any other testosterone booster, check with your healthcare provider first.

Nugenix Capsules. Photo by WellnessVerge
Nugenix capsules. Photo by WellnessVerge

Cost and Where to Buy

You’ll find Nugenix at most major retailers, including drug stores like Walgreens, Rite Aid, and CVS and supplement stores like GNC.

Nugenix Free Testosterone Booster costs $69.99 for one bottle. Each bottle contains 90 capsules for a 30-day supply, which equates to roughly $2.30 a day per serving.

In my opinion, it’s way too expensive for a single supplement.

Nugenix does back its product with a 30-day return policy.

You can find their contact information and return information on their website.

How Nugenix Free Testosterone Booster Compares to Alternatives

Most men’s testosterone boosting supplements contain proprietary blends of herbal ingredients and vitamins and minerals.

Common ingredients include zinc, fenugreek, vitamin B6, tribulus, magnesium, boron, maca. Most cost in the $20 range for a 1-month supply.

This review found that most testosterone-boosting supplements lack evidence to support their claims, and many contain high doses of vitamins and minerals that can easily approach or exceed upper limits when combined with other supplements.

The Bottom Line

Research suggests two of the ingredients in Nugenix Free Testosterone Booster, L-citrulline malate and fenugreek seed extract, may help improve sexual function, libido, and body composition.

However, the evidence is limited and suggests short-term results.

There is no evidence that taking this product will result in long-term results.

A Word from Our RD

If you suspect your testosterone could use a natural boost, there may be some lifestyle factors you can alter to help.

Not surprisingly, natural methods to boost testosterone follow the same general recommendations for good overall health.

Research has found that men who are physically active, maintain a healthy weight, and eat a nutritious diet have higher testosterone levels than those who don’t.

Other lifestyle factors, like avoiding smoking, limiting alcohol intake, and getting enough rest also play a part in maintaining healthy hormone levels. 

If you’ve already checked those boxes, I recommend checking with your primary healthcare provider before trying this or any other testosterone boosting supplement.

They can check your hormone levels, which is the only way to know for sure if you have low testosterone.

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