Damiana Supplement Mood Studies Measured Boar Sperm for Forty Days

The Oasis Health Journal · Submitted August 22, 2026 · 3:32 PM EDT

By June Mackerel · Edited by Colette Ward

Damiana, or Turnera diffusa if one is being formal about it, is a small aromatic shrub native to Central and South America. It has been used in traditional medicine as a tonic, an aphrodisiac, and a mood remedy for rather a long time. The damiana leaf extract now sold in supplement form is marketed almost entirely on those claims. The research literature, however, has taken a route that can only be described as brave.

In 2026, researchers conducted a controlled trial on four Duroc boars. Each animal received seven grams of damiana extract daily for forty days, which corresponds, as it happens, to one complete spermatogenic cycle in swine. The study measured ejaculate volume, sperm concentration, motility, agglutination, and viability during storage at twenty-four, forty-eight, and seventy-two hours. The results indicated that sperm survival at twenty-four hours improved significantly during the supplementation period, with statistical significance noted at p less than 0.01. At forty-eight and seventy-two hours, the effect was present but more modest.

One imagines the boars were not consulted.

This is, to be clear, the most rigorous controlled trial of damiana's effects on reproductive function that currently exists. Four pigs. Forty days. Refrigerated sperm. The supplement industry has built rather a lot on less, so one can see why they would be pleased.

What the Damiana Supplement Actually Does in a Dish

A 2025 study investigated the effects of a ninety-five percent ethanolic extract of damiana leaf on a series of ligand-activated transcription factors involved in metabolic regulation. The names are quite long. At a concentration of fifty micrograms per milliliter, the extract demonstrated a strong agonistic effect on liver X receptor, activating it 2.7-fold, and on nuclear factor erythroid 2-related factor 2, which increased 21.6-fold. Activation of peroxisome proliferator-activated receptors alpha and gamma was in the range of 1.4 to 1.8-fold under similar conditions. At one hundred micrograms per milliliter, the extract decreased lipid accumulation in adipocytes by 55.3 percent and increased glucose uptake in muscle cells by 91.3 percent.

These are laboratory results obtained in cell culture.

No human being took damiana and subsequently lost fifty-five percent of anything.

The study also found that damiana extract antagonised the adipogenic effect induced by rosiglitazone, a full peroxisome proliferator-activated receptor gamma agonist, reducing lipid accumulation by 57.6 percent. The authors suggested this may indicate utility in preventing the undesired adipogenic effects of antidiabetic drugs of the glitazone class. This is a polite way of saying that one drug's side effect might be countered by a plant extract, provided one is comfortable describing that as a health strategy and not simply as introducing a second variable into an already complicated situation.

The Menopause Literature Does Not Contain a Damiana Menopause Support Trial

The 2021 review titled 'Estrogenic Plants: to Prevent Neurodegeneration and Memory Loss and Other Symptoms in Women After Menopause' is cited extensively in marketing materials for damiana sexual wellness products. It is a literature review. It lists damiana among several plants that have been used for centuries to alleviate menstrual and menopause symptoms, alongside cranberry, ginger, hops, milk thistle, red clover, salvia, soy, black cohosh, and vitex. The paper notes that various plants have attracted attention for their estrogenic effects and that damiana, specifically, has traditional use in this context.

It does not report a clinical trial. It does not specify a dosage. It does not measure mood, hot flushes, sleep quality, sexual satisfaction, or cognitive function in menopausal women who took damiana.

It acknowledges that these plants exist and that people have used them.

This is not quite the same as evidence that they work, though the supplement industry appears entirely comfortable with the conflation. One might go so far as to say the industry prefers it.

The review does note that hormone replacement therapy alleviates menopause symptoms but can increase cardiovascular and cancer risk, and that medicinal plants represent a therapeutic alternative of interest. One might describe this as an invitation to further research rather than a conclusion, but marketing copy does not generally trouble itself with such distinctions. Marketing copy, as a rule, is already quite sure.

Where to Buy Damiana Leaf and What You Are Actually Buying

Damiana is available as dried leaf, tincture, capsule, and extract powder. The traditional preparation is a tea, which tastes faintly bitter and aromatic. Opinions vary on whether this is pleasant or merely tolerable. I am told it pairs well with optimism.

The extract used in the metabolic study was ninety-five percent ethanolic, and phytochemical analysis indicated flavonoids as the major constituents. The extract used in the boar study was not chemically characterised in the published report, so one cannot say with certainty what compound was responsible for the observed effect on sperm motility. Assuming it was a compound and not simply the passage of time, or the boars' own efforts, or sheer statistical noise dressed up in a bar chart.

The products marketed as natural damiana mood enhancement or damiana for mood balance do not, as a rule, specify which constituents they contain, in what concentration, or whether those constituents correspond to the materials tested in any published study. This is not unusual in the supplement industry, which operates on the principle that a plant name on a label is sufficient and that the customer will not ask uncomfortable questions about standardisation, batch variability, or whether the thing in the bottle is even the thing on the box.

If you were hoping that someone, somewhere, had conducted a proper human trial on whether a damiana supplement mood claim holds up under scrutiny, I am afraid you will be disappointed. The literature at present consists of one study on four pigs, forty days, and a modest improvement in sperm survival during refrigerated storage. That is it. That is what we have.

If you were expecting more, perhaps it is worth asking why the people selling it have not funded the study themselves. One imagines they have their reasons.

Perhaps further trials will establish what the boars apparently already know. Until then, we are left with traditional use, some promising cell culture work, and a great deal of marketing confidence that does not appear to require peer review.

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. Estrogenic Plants: to Prevent Neurodegeneration and Memory Loss and Other Symptoms in Women After Menopause, Frontiers in pharmacology (2021).
2. The Effect of Turnera diffusa Leaf Supplementation in Diet on the Qualitative and Quantitative Characteristics of Boar Semen, Life (Basel, Switzerland) (2026).
3. Damiana (<i>Turnera diffusa</i>) Reduces Adipocyte Cell Differentiation and Ameliorates Myocyte Glucose Uptake, Journal of dietary supplements (2025).