Enough randomized trials have now been run on testosterone supplements that researchers can sort them instead of guessing. The useful question stopped being whether any of them work, and became which ones, and for whom.
A 2024 systematic review in the International Journal of Impotence Research went through 52 studies covering 27 proposed testosterone boosters. Most did not raise total testosterone. Two herbs did hold up for men: Eurycoma longifolia, better known as Tongkat Ali, and Withania somnifera, better known as ashwagandha. A 2026 meta-analysis of 23 trials put a number on the second one.
Most men do not arrive at this subject through a lab result. They arrive through a week that used to be ordinary. The gym session that now needs two days of recovery. The evening that disappears into the sofa. The drive that is still there, but has to be scheduled around how tired you are.
Researchers have a name for that cluster when it shows up with age: androgen deficiency of the aging male, or late-onset hypogonadism. It is measured with questionnaires as much as with blood, because the symptoms often move before the numbers do. That matters for what follows. Several of the trials below recruited men whose testosterone was still inside the normal range, and measured whether the symptoms improved anyway.
In 2024 a team led by Morgado published a systematic review in the International Journal of Impotence Research with a blunt title: do testosterone boosters really increase serum total testosterone? They collected two decades of data, ending with 52 studies covering 27 different proposed boosters, and sorted the results by who was taking them -- athletes, men with late-onset hypogonadism, infertile men and healthy men.
Their finding was that most fail. That sounds like bad news for the category, and for most of what is sold it is. Read the other way, it is the most useful thing a buyer can have, because the same review names the survivors.
For men with late-onset hypogonadism, Eurycoma longifolia was rated possibly effective. For healthy men, Eurycoma longifolia and Withania somnifera were both rated possibly effective. Out of 27 candidates, those are the two herbs that cleared the bar in men. They are also the two that a serious formula is built around, which is not a coincidence -- the review is public and the formulators read it too.
This is the one with a number attached. In 2026 Fornalik and colleagues published a systematic review and meta-analysis in Planta Medica that pooled 23 randomized, placebo-controlled trials covering 1,706 adults, with the protocol registered in advance on PROSPERO.
Ashwagandha significantly lowered cortisol. In men, it raised testosterone by a mean difference of 57.43 ng/dl. In women it did not, which is a detail worth keeping, because it tells you the effect is specific rather than a general stimulant response.
The cortisol result is the part most people skip, and it is arguably the more interesting half. Cortisol and testosterone move against each other. A man under sustained stress is not only sleeping worse; he is running a hormonal headwind. An herb that lowers one side of that balance while nudging the other is doing something structurally different from a stimulant that borrows tomorrow's energy.
The analysis also saw signs of a dose-response pattern tied to withanolide content, which is the active fraction. That is the number to look for on a label, and almost nobody prints it.
Tongkat Ali is the ingredient that appears in both halves of the Morgado review, rated possibly effective for men with late-onset hypogonadism and again for healthy men. It is the closest thing this category has to a consensus pick.
The trial worth knowing by name is Leitao and colleagues, published in Maturitas in 2021. It ran six months, double-blind and placebo-controlled, in 45 men averaging 47 years old, all with androgen deficiency of the aging male. The dose was 200 mg a day. What makes it unusual is the design: four arms, crossing the supplement with a concurrent training programme three times a week.
Erectile function improved with both interventions. The largest improvement came from the men who did both -- the supplement and the training together.
That result is the single most practical finding on this page. The supplement was not competing with the exercise; it was compounding it. Anyone deciding whether to bother with a daily capsule while they are also trying to move more has their answer, and it is the opposite of the usual either-or.
Maca is where the honest answer gets more interesting than the marketing. In 2023 Shin and colleagues published a randomized, double-blind, placebo-controlled trial in The World Journal of Men's Health, in 80 men with symptoms of late-onset hypogonadism. They took gelatinized maca for 12 weeks.
Read the recruitment line carefully: the participants were eugonadal. Their testosterone was already in range. They had the symptoms without the lab result, which is the situation a very large number of men over 40 are actually in.
Against placebo, the maca group improved significantly on the Aging Males' Symptoms scale, on the International Index of Erectile Function and on the International Prostate Symptom Score. The share of men screening positive on the androgen deficiency questionnaire fell.
So maca earns its place for what men feel rather than for what a blood panel prints. That is a different job from the one Tongkat Ali does, and it is why the two sit well together: one works on the hormone, the other on the day.
These two are not testosterone ingredients, and a formula that pretends otherwise is selling you the wrong story. They work on circulation, which is the other half of the problem and the half that decides whether a hormonal improvement is visible.
L-arginine is the raw material the body converts into nitric oxide, the signal that relaxes blood vessels. Menafra and colleagues tested it properly: a multicentre, double-blind, randomized, placebo-controlled trial published in the Journal of Endocrinological Investigation in 2022, with 6 g a day for three months in 98 men with vasculogenic erectile difficulty. Scores improved significantly, and so did measured blood flow velocity in the penile arteries on ultrasound. By the end, 74 percent of the men had moved up a category.
Horny goat weed is the one with the unserious name and a real compound behind it: icariin. Niu and colleagues reviewed its molecular behaviour in Translational Andrology and Urology in 2022, and the mechanism is specific -- icariin acts on the same enzyme family that prescription pills target, far more weakly. The honest framing is that it is a supporting act with a plausible route, not a headline ingredient.
The Morgado review is the shopping list, and it is short. If a product's case rests on ingredients that were not among the few that held up, the case is marketing.
Four things worth checking, in order:
That last point is the quiet one. Adherence is the variable nobody markets and every trial depends on.
Yes, for two of the ingredients, with the expectation set correctly. A systematic review of 52 studies cleared Tongkat Ali and ashwagandha for men, and a meta-analysis of 23 trials put a measured testosterone increase on the second one. That is firmer ground than this category stood on five years ago.
What none of it is, is a replacement for hormone therapy. A supplement here is a potentiator. It adds to a system that is already running, and the size of what it adds depends on where you start -- your age, your sleep, how much you move, what else is going on. The Leitao trial showed that directly: the men who trained as well got the biggest result.
That is also why two men on the same bottle describe different months. The honest promise is a gradual, compounding improvement over a season, not a switch.
See the Vigor Jelly formula and pricing →The trials behind this page ran 12 weeks to six months, not days. The maca trial measured at 4 and 12 weeks; the Tongkat Ali trial ran a full six months. Judging a bottle after a week tells you nothing either way.
They are not competing. The Morgado review rated Tongkat Ali possibly effective both for men with late-onset hypogonadism and for healthy men; ashwagandha held up for healthy men and has the clearer number behind it, a mean increase of 57.43 ng/dl across 23 trials. They reach the same place by different routes, which is why formulas carry both.
It helps, but the Shin maca trial is a reminder that symptoms and lab values do not always move together: those men had normal testosterone and improved anyway. If you want a number to track, ask for total and free testosterone in a morning draw.
On the available evidence, yes, and in your favour. In the six-month Maturitas trial the largest improvement came from the group that took 200 mg of Eurycoma longifolia and trained three times a week. The two added up rather than overlapping.
The name is folklore; the compound is icariin, and a 2022 review in Translational Andrology and Urology traced how it acts on the same enzyme family prescription pills target, much more weakly. It is a supporting ingredient with a plausible mechanism, not the reason to buy a formula.
Yes, particularly if you take blood pressure medication, blood thinners, thyroid medication or anything for the prostate. Ashwagandha affects thyroid hormone levels and L-arginine affects blood vessels, so both are worth mentioning.
This article is for general information and is not medical advice. Talk to a healthcare professional about your own situation, especially before combining a supplement with prescription medication.