Testo Lab Pro Review: A Science-Backed 38% Testosterone Upgrade?

This review is an update to a previous review on the same product, which has since had a major overhaul to its dosing, naming and branding.  

What was once called "Performance Lab SPORT T+" is now renamed "TestoLab Pro T-Booster" by Opti-Nutra.

With a new handle, fresh coat of paint, and revamped dosing recommendation, we put this upgraded formula to the test to determine, once again, if there's a formulation that can quantitatively and qualitatively move the needle on testosterone enhancement.

As stated in the original write up:

"Post-regulation of T precursors, supplement companies have had to reach far and wide to identify other natural ingredients that impart some effect on the testosterone pathway.  Is there supplement combo that can match the effectiveness of the “andro” days?"

OptiNutra is certainly trying. And, the answer to the question above is leaning towards the postive side of the spectrum.  

Here's what TestoLab Pro claims about their product on their website:  

  • "Increases testosterone levels safely & naturally"
  • "Protects, sustains & potentiates circulating T"
  • "Boosts muscle grwoth, strength & athletic prowess"
  • "Invigorates masculine energy, virility & potency"

These are some mighty bold claims for a supplement, in my opinion. 

So I decided to put this formula to the test, subjectively and objectively, by taking the prescribed dose (2 caps twice per day) for 90 days.  Subjective observations were made throughout the 3 month-long trial period, as well as before and after blood analysis of male hormone markers. 

Does this formula increase testosterone, as the company claims it does? 

Let’s find out below


Testo Lab Pro® Review Summary:


  • Supports & Maintains Testosterone through multiple pathways
  • The chosen ingredients are supported by science.
  • Does not need to be cycled - can be used year-round
  • After lab testing, this product led to a 38% increase in testosterone for me!
  • The product boosted my libido, strength, and endurance


  • Relatively pricey
  • Might build up mineral imbalances, such as too much zinc and too little copper, over time

Conclusion: an excellent all-round testosterone booster that contains many high-quality ingredients and has impeccable quality standards.



My Experience Taking TestoLab Pro

As described above, I took the recommended 4 caps per day for 90 days.  During the trial period, I followed a consistent diet and exercise routine and avoided any significant changes in lifestyle factors in the interest of minimizing external influence hormone signaling and production. 

For baseline reference, I'm Joe, I'm a 44 YO male who’s diet & exercise program is geared towards health optimization and longevity. 

I run 3-4 days per week, with most sessions being 4-mile jogs @ 7:30/mile pace. 

One session per week is high intensity sprinting. Another day a week is dedicated to resistance training, where I focus 30 minutes on deadlift, squat, or bench plus a couple of complimentary lifts. Diet is low carb, no sugar with occasional 24-36hr fasts.

My program is not quite keto, as total carbohydrate intake is usually 50 grams per day. No fasting was performed during the T+ trial period. 

I’ve divided my experience with TestoLab Pro into two sections, the objective lab data, and subjective observations. Let’s start with the subjective section.


My Subjective Experience Taking This Testosterone Booster

Prior to starting the supplement, I decided I was going to track 4 subjective criteria that are tied to testosterone levels in males.  These include libido, mental focus, emotional lability, and strength/endurance. 

I would make a mental note of each factor on a daily basis and complete a subjective self-assessment on a weekly basis.  I used a 3-point rating scale where “2” represents neutral/no change, “1” represents a decrease and “3” represents an increase. I have condensed the 12 weeks into a 3-month summary. 

Here are the results:



Mo. 1

Mo. 2

Mo. 3








Mental Focus






Emotional Lability






Strength Endurance







From a baseline perspective, I feel fortunate to have a normal functioning libido, pretty good mental focus, stable emotional lability, and decent strength/endurance for a guy my age.  

As you can see from the table above, not a whole lot changed in my four subjective criteria.  The most notable effect I experienced during the trial period was a modest increase in libido during the final weeks of the trial period. 

I did not experience any noticeable change in my ability to focus, speed to anger or change in stress tolerance. I did experience a modest improvement in strength and endurance in the final month as well. 

In summary, the subjective changes I experienced while taking TestoLab Pro was a modest spike in my libido and most increase in strength and endurance during the last 3-4 weeks of the 3-month trial.   


Let’s switch gears to the lab data:


My Lab Testing Results With This T-Booster

I utilized the “Let's Get Checked” at-home lab service to collect before and after samples. 

The “Before” sample was my baseline, taken the morning immediately prior to my first dose of the supplement.  The “After” sample was taken the morning of the 31st day following the completion of a 3-month supply of the product. The test performed was the “Male Hormone ” package, including the biomarkers listed in the table below. 

What follows is my interpretation of the observed changes in the biomarkers.  I caution readers to keep in mind that n=1, which, as I trust you know, does not imply any degree of statistical significance.  

On the whole, each result for the biomarkers tested landed inside the laboratory’s reported reference ranges.  As such, baseline markers coming into the supplement trial were already in good shape.  


There are myriad sources on the web where one can find thorough explanations of the physiological roles of each of the biomarkers assessed, so I’ll refrain from offering those here, aside from a brief comment on directionally which way a male interested in boosting T would want to see that go.


Testosterone-Related Biomarkers

Here's an explanation of the lab outcomes listed above:


Sex Hormone-Binding globulin (SHBG) is a protein that transports sex hormones around the body. 

When the hormone is bound to SHBG, it cannot perform its programmed function. As such, lower levels are generally more desirable when boosting T, as this results in more “free” T, the form that does the heavy lifting for men. My results showed a 56% increase in SHBG, despite there being at least one nutrient in the formula, boron, that has been shown to decrease SHBG levels. 

The free androgen index is a ratio of free testosterone to SHBG. The 15% drop experienced between baseline and treatment was driven by the change in testosterone and SHBG. This value dropped because SHBG rose at a higher percentage than T over the course of the experiment.

Speaking of testosterone… 

Obviously, this is the marker of greatest interest. My results showed a 38% increase from baseline. This is encouraging data, however it must be interepreted through the lens of n=1.  

I’ll elaborate on this observation in the section following the ingredient review.  Let’s switch gears to explore the science behind the formula.  


Scientific Review Of Ingredients

Below I've reviewed all ingredients in TestoLab Pro:


1. Vitamin D, 50 micrograms (mcg), 250% of Daily Value.

The impact of Vitamin D on testosterone has been pretty thoroughly studied with results generally supporting positive impacts on male testosterone levels, especially in those where both vitamin D levels as well as testosterone levels were considered low at baseline (1). 

Of interest, there is research showing that Vit D treatment has no effect on total testosterone levels in middle-aged healthy men with normal baseline T levels (2). This is where devilish details come back to bite. 

For many T-boosting supplements, the target audience is healthy young-middle aged men who likely already have normal baseline T levels, where Vit D may not have an impact on these individuals.   

Verdict: While many studies show that Vitamin D has a positive impact on Testosterone, it likely requires that one already has low Vit D and low T for vitamin D supplementation to meaningfully impact T levels.


2. Vitamin K1 and K2, 50 mcg, 42% of Daily Value.

Vitamin K is often found in vitamin D supplements. This is because one of the primary roles of vitamin D is to facilitate calcium metabolism. In this process, vitamin K helps vitamin D do its job more effectively. 

What does this have to do with enhancing testosterone?  Well, I think the jury is still out on that.  A review of the scientific literature yielded little information on the role of vitamin K in testosterone production.  A single study performed in rats showed that vitamin K deficiency decreased T production and that administration of vitamin K reversed inflammation-induced T suppression in rats (3).

Not exactly a slam dunk here.  Scientific research on the role of vit K on testosterone is limited and it is hard to make any claim of relevance. 

Verdict: Vitamin K is often coadministered with Vitamin D to help with calcium metabolism and its effects on testosterone are unclear.


3. Magnesium, 50 mg, 12% of Daily Value. 

Research suggests that magnesium influences testosterone by at least two indirect methods. 

Sex hormone-binding globulin (SHBG) is a protein whose job is to attach to circulating hormones like testosterone.  When these two molecules are linked up, the hormone is not able to perform its normal signaling function. As such, higher levels of SHBG are undesirable to someone trying to raise testosterone. SHBG can also be attached to mineral cations like calcium, zinc, and magnesium.

Research shows that administering magnesium can “tie up” SHBG, leaving more free testosterone to go about its business (4).  

The second method by which magnesium exerts a positive effect on testosterone is an even more indirect method than what is described above. 

This pathway involves the immune system. High levels of inflammation secrete chemical messengers, called cytokines, that suppress testosterone production.  Research has shown that magnesium can modulate oxidative pathways that result in immune activation, thereby dampening a system's inflammatory load (5).    

Verdict: Some evidence suggests magnesium has positive, indirect effects on testosterone maintenance, however, many positive outcomes are linked to older males who have experienced age-related T decline.


4. Zinc, 30 mg, 272% Daily Value

Zinc and testosterone have a long and well-studied history, with the discovery of the relationship between zinc deficiency and hypogonadism dating back to the 1960s (6).

Additional work has linked zinc as an important cofactor to enzymes responsible for the entire testosterone synthesis pathway. However, much like the other minerals & nutrients discussed here, discovering an essential role for an ingredient in a hormone synthesis pathway does not always translate to increase hormonal production when that ingredient is supplemented. In many circumstances, the nutritional status of the individual plays a significant role on the effect of supplementation.  

A well designed 2007 study in the European Journal of Clinical Nutrition explored the effect of zinc supplementation on various biomarkers, notably zinc and testosterone, in young, exercising men. The study concluded that the use of the zinc supplement had no significant impact on serum free and total testosterone levels. The authors went on to conclude that it is unlikely that individuals with balanced dietary zinc status will not benefit from zinc supplementation (7).

Verdict: Zinc’s role in testosterone synthesis & maintenance is well established, however, supplementing with this mineral in the absence of zinc deficiency is unlikely to lead to increased testosterone production. 


5. Boron, 6 mg, no daily value established

Boron’s role in testosterone enhancement is intriguing and seemingly multifactorial. 

A thorough published review on its various effects have identified that boron increases free testosterone, decreases estradiol, and decreases inflammatory biomarkers, after only 1 week of supplementation (8).

Another study has shown that boron supplementation in healthy males led to a significant decrease in sex hormone-binding globulin, consequently resulting in higher levels of free testosterone (9). 

Verdict: Of the minerals purported to boost testosterone, boron appears to be the best-studied and most impactful in healthy, active males. 


6. KSM-66 Ashwagandha Extract (Withania somnifera, 5% withanolides) 600 mg.

Extracts of this Ayurvedic medicine herb have been promoted to have positive impacts on youthful vigor, muscle strength, and endurance.

A 2019 double-blind, placebo-controlled study in overweight men aged 40-70 years found a 14.7% increase in testosterone compared to placebo (10). While the design of this study appears to be rock solid and the outcome favorable, there remain questions as to the impact this ingredient has on healthy, athletic males.  

A 2015 study did investigate the impact of this herb on athletic males and found that an 8-week trial resulted in significantly greater muscle size, reduction in exercise-induced muscle damage, a significantly greater decrease in body fat, and significantly higher testosterone levels (11). 

The manufacturer makes some interesting claims about this particular ingredient.  Of note, they state: "KSM-66® is the strongest full-spectrum ashwagandha extract – standardized for 5% active withanolides. KSM-66® is also the only 100% Organic Certified ashwagandha."

They go on to claim that KSM-66 optimizes the hypothalamic-pituitary-adrenal axis, stimulates lutenizing hormone and follicle-stimulating hormone (which signal for testosterone production) and supplies antioxidant activity to fight free radicals that impact testosterone production.  

I did not see any references that back up the aforementioned claims. 

Verdict: The body of literature on this herb is surprisingly robust and encouraging, suggesting that this ingredient should be a staple of any testosterone-enhancing supplement.


7. D-Aspartic Acid Calcium Chelate, 600 mg.

D-Aspartic Acid Calcium Chelate (DAACC) is an amino acid purported to enhance testosterone.

In my search for published literature exploring the effects of this supplement, I stumbled across systematic review that is arguably the most comprehensive synthesis of scientific information on D-AA-CC to date. The authors state that results from 23 animal studies showed a positive effect on testosterone levels whereas results from 4 human studies were inconclusive (12). 

A 2015 study exploring the effects of relatively high doses of D-AA-CC (3 grams/day & 6 grams/day) on resistance-trained men found no difference in serum T levels after 14 days of supplementation (13). 

Of interest, an online supplement seller (not the manufacturer of TestoLab Pro) promoting the use of D-Aspartic Acid for testosterone enhancement references a handful of weak studies but then goes on to state “for active men, the increase in testosterone levels is not significant”.

The manufacturer claims D-AA-CC stimulates release of luteinizing hormone and growth hormone, but again does not offer any references to substantiate these claims. 

Verdict: DAACC appears to be an effective T enhancer in animals, but the evidence for boosting T in active males is insufficient.   


8. Mucuna Pruriens Extract (15% levodopa), 300 mg.

Mucuna Pruriens is a herb that contains the dopamine precursor, levodopa.

The 300mg dose at 15% standardization provides a meaningful amount of levodopa.  It appears that the administration of a dopamine precursor leads to increased dopamine production, which then positively influences the hypothalamus-pituitary-gonadal axis by upregulating the production of luteinizing hormone (LH) and consequently testosterone. 

Treatment with the levodopa resulted in increases in T, LH, and dopamine in infertile males (14). A fairly robust body of knowledge has explored the impacts of mucuna on androgenic processes in rat models and it appears to have significantly positive effects, however, the number of studies replicating these findings in athletic males is small, with the bulk of evidence focusing on male fertility (15).

Verdict: promising ingredient that has some studies suggesting benefits. Dose is good.


9. Luteolin (from orange extract), 60 mg.

Luteolin is a flavonoid molecule with documented ability to inhibit the estrogen synthesis enzyme aromatase.  Much of the work on this nutrient has focused on its potential use in slowing down estrogen-dependent cancer cell proliferation (1617). 

This is encouraging work, carving out a potentially useful niche for this supplement.  Frustratingly, it appears the supplement industry has taken the luteolin research applied to cancer cell aromatase inhibition and applied it to testosterone enhancement in men. 

I was unable to find any published literature demonstrating altered serum hormone levels in athletic men, therefore its utility in a T-enhancing formula remains speculation based on a hypothetical model.  

Final comment on this: having observed a 47% reduction in estradiol levels between my baseline and treatment sample in the initial review of the formulation, is it possible that luteolin inhibited estradiol conversion, leading to the results observed? 

Verdict: Luteolin has demonstrated anti-aromatase properties, but no studies in athletic males have shown enhanced T and/or decreased estrogen.  

My Assessment Of TestoLab Pro

If you’ve made it this far, there appears to be a spectrum of positive, neutral, and negative pieces of evidence tied to the outcome of this review. The lab results showed a positive direction testosterone levels over the course of 3 months. 

All of which need to be taken with a grain of salt given the n=1 sample size. The subjective measures showed repeated positive movement in libido, modest increase in perceived strength and endurance, and no perceptible change in emotional lability, or mental focus. 

The scientific review of the ingredients showed that many have science backing their inclusion in a testosterone-enhancing formula, but there are often caveats to when these ingredients may show benefit. 

Notably, many ingredients only show a response when it is known that there is a baseline deficiency and/or the user is a non-athletic male who’s testosterone may already be low. 

I remain particularly intrigued by the KSM-66 Ashwagandha included in this formula, as there seems to be a robust amount of data supporting its role in boosting T, notably in active men.  

I still can’t help but wonder if this formula would provide greater tangible benefits for more intensive athletes. 

While much of the science on the ingredients suggests that greater response is found in those who are deficient, the higher physical stress and turnover rate of nutrients in high performing athletes may put them in states of deficiency that the supplement could provide. 

The company’s website seems to be geared towards catering to this demographic, with a messaging emphasis on “All Man. Testosterone. Muscle. Sex.” I appreciate the crisp, manly design of their webpage, but the science geek in me was left wanting more evidence backing claims made.  

While I did find a couple of graphs documenting the impact of a couple of ingredients, not a single referenced scientific study could be found.  


Finishing Thoughts: The Best-Researched Formula On The Market?

In the post-andro era, we are left with few natural ingredients that can raise testosterone.  With that in mind, I feel that the TestoLab Pro formula does a good job of combining what appears to be the best-researched combo of ingredients on the market. 

The formula would likely offer the most benefit to those who are deficient in zinc, boron, magnesium & vitamin D, and possibly those who are sedentary or high-level performers who are not adequately replacing lost nutrients.

I remain open to the idea that this formula is beneficial to weekend warrior types, supported by my repeated experience with increased libido while using the product.

Interestingly, amidst the major overhaul from the first generation of the product, they simply doubled the daily dose of each ingredient.  I find myself asking "why". Regardless, the company's decision may have paid off, if my own qualitative and quantitative measures are an indicator of what one can expect from using the product. 

In summary, it's a solid formula that would benefit from larger-scale trials to determine its impact on testosterone. 

This is a post by Joe Ailts. Joe has completed degrees in biotechnology (BS) and nutrition (MS) and is a science writer for Alexfergus. He has 14 years of experience in the clinical laboratory arena as well as in the dietary supplement industry.


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