Testosterone Boosters vs TRT: What the Ingredient Literature Actually Shows

Someone looked directly at this question. Researchers took the five highest-rated, most-reviewed testosterone-boosting supplements on Amazon, catalogued their ingredients, and went to the literature on each one.[1] The result is the most useful thing available for anyone weighing a supplement against prescription therapy, and it is worth reading before spending money in either direction.

What they did

The Amazon marketplace was searched for "testosterone" + "booster" with default settings, and the top five products by relevance on 22 July 2018 were reviewed for price, ratings, reviews, manufacturer details and ingredients.[1]

Those five products carried an average of 2,761 reviews and an average rating of 4.56 stars.[1] Whatever else is true, these are not obscure products.

What the ingredients are backed by

19 unique ingredients appeared across the five supplements. For the 10 most common, the researchers found 191 studies.[1]

The composition of that literature is the first finding:

Study type	Share of the 191
Human subjects	19%
Animal models	53%
In vitro	15%
Case reports or reviews	12%

Four in five studies behind the ten commonest ingredients were not conducted in people.

Narrowing to the 37 human studies:[1]

30% observed an increase in testosterone levels · 3% a decrease · 46% no effect · 22% indeterminate.[1]

Nearly half of the human research on these ingredients found no effect on testosterone. Under a third found an increase — and an increase in a measured level is not the same as a clinical benefit.

The authors' conclusion is unambiguous: limited human studies have evaluated these products, resulting in no definitive findings of efficacy, and patients should be cautioned before considering them given the availability of highly effective FDA-approved therapies.[1]

The part about the reviews

The 4.56-star average is the reason most people buy these products, so the researchers tested it. They categorised top customer reviews using themes from the Androgen Deficiency in the Aging Male questionnaire, then re-analysed after filtering untrustworthy comments with review-analysis software.[1]

What survived filtering:

• 91% decrease in users reporting increased libido
• 93% decrease in reports of improved strength or endurance
• 89% decrease in reports of improved sports ability
• 67% decrease in reports of improved sleep
• 60% decrease in reports of improved erections
• 59% decrease in reports of increased energy
• Elimination of reports of improved work performance[1]

Nine in ten of the strongest efficacy claims in the reviews did not survive a filter for untrustworthy comments.

The researchers are explicit about the limits of their own method — selection bias, a small number of supplements, and proprietary review-analysis software they did not control.[1] That is a fair caveat. It does not make a 91% attrition rate uninteresting.

How this compares with prescription therapy

The comparison is not close, and it is not close in a specific way.

Testosterone therapy has a characterised effect and a characterised limit. In symptomatic men over 65 with confirmed low testosterone, one year of treatment produced a moderate benefit for sexual function, some benefit for mood, and no benefit for vitality or walking distance.[2] That is a narrower claim than any supplement makes.

It is also a diagnosis-gated treatment. The Endocrine Society recommends against prescribing testosterone without a confirmed diagnosis, and formulation choice is weighed against pharmacokinetics, preference, adverse effects, burden and cost.[3] A supplement asks none of those questions.

The honest framing is this: prescription therapy is held to a standard that reveals its limits. Supplements are not held to that standard, which is why their claims are broader.

What to do with this

1. If the symptoms are real, get the level measured. A confirmed diagnosis determines whether testosterone is even the right question. Historically, roughly a quarter of men starting therapy in the US had no testosterone measurement in the prior year — see how prescribing tripled.
2. If the level is normal, testosterone is not the answer either. Fatigue and low libido have other causes, covered in fatigue and low libido after 40.
3. Tell your provider what you are taking. Supplement products are not uniformly what their labels say, and that is a safety matter rather than an efficacy one.

Bottom line

The most popular testosterone boosters are built on ingredients whose human evidence is thin and mostly negative or indeterminate, and their consumer reviews lose the large majority of their efficacy claims when filtered.

Prescription testosterone therapy does work, for a narrower set of outcomes than either supplements or its own marketing suggest, in men who actually have low testosterone. The first step is not choosing between the two products — it is finding out which category you are in.

References

3 sources

1. Balasubramanian A, Thirumavalavan N, Srivatsav A, et al. Testosterone Imposters: An Analysis of Popular Online Testosterone Boosting Supplements. J Sex Med. 2019;16(2):203–212. doi:10.1016/j.jsxm.2018.12.008 · PMID 30770069
2. Snyder PJ, Bhasin S, Cunningham GR, et al. Effects of Testosterone Treatment in Older Men. N Engl J Med. 2016;374(7):611–624. doi:10.1056/NEJMoa1506119 · PMID 26886521
3. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. doi:10.1210/jc.2018-00229 · PMID 29562364