Do Testosterone Boosters Work?

The claim

Testosterone boosters are sold on a simple promise: take this, raise your testosterone, get bigger and stronger and generally more of a man.

The category is enormous and mostly herbal. Tribulus, ashwagandha, fenugreek, zinc blends, proprietary formulas with names designed to sound clinical.

Here is the pattern that runs through the evidence I found, and once you see it you can apply it to almost any product in this aisle.

Who is actually taking this stuff

Researchers surveyed Italian gyms and fitness clubs between May and October 2024. Of 696 people who started the questionnaire, 510 valid responses were analysed.

Current use of Tribulus terrestris was reported by 7.8 percent of respondents.

The paper's own framing of the product is worth quoting for its bluntness: it is marketed to enhance fitness performance despite inconclusive evidence regarding its efficacy and safety.

The study also examined risk behaviours associated with dietary supplements and anabolic steroids together, which tells you something about the neighbourhood these products sit in. The researchers were interested in whether supplement use tracks alongside riskier choices.

This is a survey. It describes who uses it and why, not whether it works.

A herb, eight weeks, and no difference

Twenty-four moderately active participants were randomly assigned to either Astragali radix supplementation or a placebo. Everyone did 8 weeks of resistance training at three sessions per week, then 2 weeks of intensified training at six sessions per week.

Strength was measured three ways: maximal voluntary isometric contraction of the knee extensors, leg press one-rep max, and leg extension one-rep max. Blood was drawn for inflammatory markers and testosterone.

From baseline to after the eight weeks of training, all three strength measures increased in both groups, with no differences between them.

So the training worked. The supplement added nothing on top.

That is the shape of most of this category. The people taking the product get results, because they are training. The placebo group gets the same results, because they are also training.

Twenty-four participants split into two groups is small, so this could miss a modest effect. But small is also the norm in this literature.

The free version does not work either

Cold exposure is the non-supplement member of this family. Cold showers, ice baths, the whole thing, widely claimed to raise testosterone.

Eleven current or former male college athletes took 10-minute cold showers at 17 degrees Celsius for four consecutive days. Salivary testosterone was sampled before the first shower and again at the end.

It did not increase.

Eleven people over four days is a small, short study, and the authors present it as a research communication rather than a definitive answer. But it points the same direction as the supplement evidence: the intervention that is supposed to raise testosterone did not raise testosterone.

Now the study where it did work, and why it does not apply to you

This is the important one, because it is how these products get their marketing material.

Sixty men took part in a 90-day multicentre randomised, double-blinded, placebo-controlled trial of a standardised polyherbal formulation. Proper design.

The results were real. Sperm count rose 72.5 percent against 8.6 percent in placebo. Motility rose 14.4 percent against 6.3 percent. Serum total testosterone rose 23.3 percent.

A 23 percent testosterone increase in a well-designed placebo-controlled trial. That is exactly the number a supplement company puts on a label.

Here is what the label will not tell you. Every participant had oligospermia, clinically low sperm count. They were recruited because they had a diagnosed fertility problem.

That is a completely different situation from a healthy 22-year-old with normal testosterone. When a system is impaired, correcting it can produce large changes. When a system is already working, there is nothing to correct.

This is the single most useful thing to understand about this entire category. Read who was in the study before you read what happened to them.

What actually moves testosterone

The boring answers, and none of these came from the studies above, so treat this as context rather than evidence from this piece: sleep, bodyweight, training, and not being deficient in things you should not be deficient in.

If you genuinely suspect low testosterone, the move is a blood test and a doctor, not a tub. Real deficiency is a medical condition with medical treatment, and the trial above is a reminder that when there is a genuine problem, treating it properly produces genuine numbers.