Muira Puama Sexual Function Studies Are Mostly Rats

The Oasis Health Journal · Submitted October 4, 2026 · 10:00 AM EDT

By Marlo Quist · Edited by Priya Raman, C.N.C.

Muira puama is a Brazilian bark sold in supplements for sexual function. The bark has been used in traditional medicine for a long time. The supplements are available now.

The human evidence is not.

What exists is mostly rats.

The Rat Study Was Encouraging for Rats

In a 2024 trial published in Sexual Medicine, researchers injured the pelvic neurovascular supply in rats, then treated some of them with an herbal blend that included muira puama, guarana, ginger and L-citrulline. After six weeks, the treated rats showed significantly better erectile function recovery than the control group. Intracavernous pressure measurements were higher. Smooth muscle content was preserved. Neuronal markers improved.

The rats recovered.

You are not a rat with a surgically induced pelvic injury being treated in a controlled university setting. That is a different scenario. The study establishes that the blend did something measurable in that specific injury model. It does not establish what happens when a human man takes a muira puama supplement he bought online and hopes for the best.

The Cells Responded in a Dish

A 2021 study in Translational Andrology and Urology took human corporal smooth muscle cells and treated them with a commercial muira puama sexual function product in a laboratory dish. The cells increased production of inducible nitric oxide synthase, nitric oxide and cGMP. All of those are involved in the erectile process. The effect was blocked when researchers added an iNOS inhibitor, confirming the pathway.

Your cells are not in a dish.

That is also a different situation. Cells in culture do not have a circulatory system, a nervous system, a liver that metabolises things or a digestive tract that decides what gets absorbed. A dish is a clean room. A body is a committee that argues about everything and files paperwork wrong.

The study shows the ingredient can activate a relevant pathway under ideal conditions. It does not show what happens when you swallow a capsule and wait.

What the Reviews Found

A 2020 review in Sexual Medicine Reviews evaluated common ingredients in erectile dysfunction supplements. The authors found that although L-arginine had clinical data supporting improved function, most other ingredients, including muira puama, had limited evidence in humans. The review concluded that ED supplements remain poorly studied and that further research is required to determine efficacy.

Further research is academic for "we do not know."

A 2019 analysis in The Journal of Sexual Medicine examined the top-rated erectile dysfunction supplements on Amazon. Across six products, 21 ingredients appeared. The researchers found 413 studies involving those ingredients, but only 59 involved human subjects. Of those, only 12 studies tested individual ingredients and reported improvement.

Muira puama appeared in multiple products. Strong evidence for it did not.

The Supplement Market Does Not Wait for Evidence

You can buy muira puama extract in capsules, powders and combination formulas marketed as natural sexual performance support or mens vitality enhancement supplement products. The labels talk about traditional use. They talk about herbal wisdom.

They do not talk about the size of the human trials because the human trials are not there yet.

The Amazon analysis found something else interesting. When researchers used review-filtering software to remove suspicious comments, the reported benefits dropped sharply. Reviews claiming improved erection strength fell 77 percent. Reviews reporting increased confidence dropped 89 percent.

The ratings looked good until someone checked whether the ratings were real.

If you search for muira puama sexual function supplements, you will find products. You will find star ratings. You will find testimonials that sound like they were written by the same person in different hats. What you will not find is a published human trial that enrolled men, gave them muira puama by itself, measured sexual function with a validated instrument and reported results in a peer-reviewed journal.

That study has not been done.

Where the Dosage Comes From

The rat study used 45 milligrams per kilogram of body weight daily, delivered in peanut butter. For a 180-pound human, that would be about 3,700 milligrams a day, except you cannot scale a rat dose to a human that way because metabolism is not linear. The cell study used concentrations measured in micrograms per milliliter in a culture dish, which does not translate to a capsule dose at all.

Commercial products contain anywhere from 250 milligrams to 1,500 milligrams per serving. Those numbers are not based on human efficacy trials. They are based on traditional use references, the amount that fits in a capsule and what other companies are putting on their labels.

The dose is a guess that sounds official because it is printed on a bottle.

How This Compares to Other Options

If you are comparing muira puama to other male performance supplements, you are comparing weak evidence to weak evidence in most cases. L-arginine has some human data. Ginseng has some human data. Horny goat weed has mostly tradition and one small trial. Tongkat ali has a few studies.

Muira puama has the rats and the dish.

The fact that an ingredient appears in a traditional system does not mean it does not work. It means we do not know yet. The fact that it activates a pathway in cells does not mean it is useless. It means the next step is a controlled human trial, and that step has not happened.

The industry sold the product before the research arrived. That is how the industry works. It always has been.

What You Are Actually Buying

When you buy a muira puama supplement, you are buying a bark extract that has been used traditionally, that did something measurable in rats with pelvic injuries and in human cells in a dish, and that has not been tested in a proper human trial for sexual function.

You are also buying the hope that traditional use means something. Which it might.

You are not buying proof.

The research that exists is not fake. It is incomplete. The pathway work is real. The rat work is real. The gap is the part where someone gives it to a hundred men for twelve weeks and measures what happens with a validated questionnaire and publishes the results where other researchers can check the work.

That has not been done.

The supplement is available. The evidence is not. Those are two separate facts and the industry would prefer you did not notice.

This article is education and reporting on published research. It is not medical advice, and nothing here is intended to diagnose, treat, cure or prevent any disease. Talk to your own clinician about your own situation.

Sources

1. Nutraceutical and low energy shockwave treatments improved sexual function recovery in a rat pelvic neurovascular injury model, Sexual medicine (2024).
2. Activation of the iNOS/NO/cGMP pathway by Revactin® in human corporal smooth muscle cells, Translational andrology and urology (2021).
3. Efficacy and Safety of Common Ingredients in Aphrodisiacs Used for Erectile Dysfunction: A Review, Sexual medicine reviews (2020).
4. An Analysis of Popular Online Erectile Dysfunction Supplements, The journal of sexual medicine (2019).