Damiana

Turnera diffusa Willd. ex Schult. was published in 1820 by Josef August Schultes, who credited the name and description to the German botanist Carl Ludwig Willdenow, according to Kew’s International Plant Names Index (IPNI). Kew’s World Checklist of Vascular Plants, the dataset behind Plants of the World Online, accepts the name and treats several others as synonyms, including Turnera aphrodisiaca Ward, published in the Virginia Medical Monthly in 1876, Turnera diffusa var. aphrodisiaca (Ward) Urb., published by Urban in 1883, Turnera microphylla Desv., and Turnera pringlei Rose. In other words, the “aphrodisiac” variety that supplement labels and some studies still name is not recognized as a separate plant in that checklist, although Mexican researchers sometimes compare samples labeled var. diffusa and var. aphrodisiaca. Older literature places the genus in its own family, Turneraceae; current classifications put it in Passifloraceae, the passionflower family. Szewczyk and Zidorn (Journal of Ethnopharmacology 2014) count about 135 accepted Turnera species, of which roughly half a dozen are used in traditional medicine.

The checklist gives a native range from Texas across Mexico, including the northwest that holds Baja California, through Central America from Belize to Panama, across the Caribbean from the Bahamas, Cuba, Hispaniola, Jamaica, and Puerto Rico to the Leeward Islands, and to northeastern and southeastern Brazil. The Flora of St. John (Memoirs of the New York Botanical Garden) describes an erect or spreading shrub 15 to 70 cm tall, many-branched from a woody base. Its leaves are alternate but look whorled because short side shoots crowd them together; each blade is only 4 to 10 mm long, obovate or lance-shaped, leathery, densely hairy especially beneath, with a toothed margin. The nearly stalkless flowers have spoon-shaped yellow petals 4 to 6 mm long, and the fruit is a small, nearly round capsule that splits to the base. Flora de Nicaragua records plants up to 2 m tall on beaches, in dry tropical forest, and in savannas on rocky soils, notes that the flowers are heterostylous (individual plants carry styles and stamens at different heights, which favors cross-pollination), and calls the plant medicinal and very aromatic.

The leaves, often with the flowering tops, are the part used: the first National Formulary of 1888 made its fluid extract from the leaves, US food rules list damiana leaves as a flavoring, and the German medicine is a leaf extract. Szewczyk and Zidorn list flavonoids (22 compounds across the genus), cyanogenic glycosides (seven), maltol glucoside, phenolics, mono-, sesqui-, and triterpenes, and fatty acids in Turnera. Spencer and Seigler (Planta Medica 1981) isolated the cyanogenic glycoside tetraphyllin B from damiana, Piacente and colleagues (Zeitschrift für Naturforschung C 2002) isolated flavonoids and arbutin from an infusion of the aerial parts, and Zhao and colleagues (Journal of Natural Products 2007) characterized 35 compounds, including glycosides of apigenin and luteolin. Kumar and colleagues (Indian Journal of Pharmaceutical Sciences 2008) found most apigenin bound as glycosides, with the most in the flowers, then the leaves. Some reviews also list caffeine, but Pauli and colleagues (Planta Medica 2026) traced that claim to erroneous or circular citations and detected no caffeine in authenticated damiana, at a limit equivalent to less than 4 micrograms per daily serving.

Damiana is a plant of Mexico’s dry lands. Dávila-Rangel and colleagues (Plants 2024) describe it as one of the most important medicinal plants of the Maya and note its use in Mexico’s arid and semi-arid zones against cerebral weakness, impotence, inflamed testicles, and respiratory complaints such as coughs and colds. Szewczyk and Zidorn call it one of the most highly appreciated plant aphrodisiacs, and record other uses of Turnera species for anemia, bronchitis, diabetes, fever, digestive complaints, pain, skin disorders, and women’s health problems, and as abortives (to end pregnancy), expectorants, and laxatives. The natural products monograph on Drugs.com credits the Spanish missionary Juan María de Salvatierra with the first report that Indigenous people in Mexico made a sweetened drink from the leaves for its love-enhancing properties. In the Los Cabos mountains of Baja California Sur, Pío-León and colleagues (Acta Botanica Mexicana 2018) found that ranchers drink teas of 12 wild plants, mainly as cold and cough remedies and general relaxants, and that damiana had the highest cultural value of all (71.2%). Juárez-Aragón and colleagues (Frontiers in Nutrition 2024) describe damiana liqueur as drunk for toning, relaxing, and supposedly aphrodisiac effects, and note that in Mexico the plant is mixed with tequila or mezcal to make relaxing and sexually stimulating drinks.

The American career of damiana was a product of the patent medicine era. The same monograph records that it was imported in the 1870s as a tincture advertised as a powerful aphrodisiac for “the enfeebled and the aged.” Medical journals joined in: PubMed indexes an 1875 item by J. J. Caldwell in the Atlanta Medical and Surgical Journal announcing damiana as a new aphrodisiac, and an 1879 item in the same journal promoting it as a nerve tonic, while the botanical name Turnera aphrodisiaca was coined in the Virginia Medical Monthly in 1876. The first National Formulary of the American Pharmaceutical Association (1888) included a fluid extract made from the leaves of Turnera species “(Damiana)” and an Elixir of Damiana. According to that monograph, damiana never entered the United States Pharmacopeia; the elixir was dropped from the National Formulary in 1916, and the fluid extract and leaf remained until 1947. The same source suggests that irritation of the urinary passages by the volatile oil may explain the aphrodisiac reputation, the view associated with Tyler’s 1983 “herbal hoax” article in Pharmacy in History.

Damiana’s later history runs in three directions. Germany’s Commission E reviewed “damiana leaf and herb” in 1989 and placed it among the herbs it did not approve. From the late twentieth century damiana reappeared as a “legal high”: Dennehy and colleagues (Annals of Pharmacotherapy 2005) found it in 10% of 119 herbal products sold online for recreational use, and Ogata and colleagues (Forensic Science International 2013) frequently found damiana DNA in 62 “Spice”-type herbal smoking mixtures from Japan’s illegal drug market, where plant material mainly served as a carrier for synthetic cannabinoids. Louisiana now lists damiana among the “prohibited plants” in a law first enacted in 2010. Meanwhile it became a standard ingredient of sexual enhancement supplements, from ArginMax to VigRX Plus, and in Germany a damiana leaf extract is now registered as a traditional herbal medicine for waning sexual desire.

The aphrodisiac evidence comes from rats. Arletti and colleagues (Psychopharmacology 1999) gave male rats a damiana fluid extract by mouth at 0.25 to 1 ml per kg: it had no effect on sexually potent rats, but at the highest dose it increased the share of sexually sluggish or impotent rats that ejaculated and shortened the time to mounting and ejaculation, without changing general activity. Estrada-Reyes and colleagues (Journal of Ethnopharmacology 2009) found that 80 mg per kg of a water extract helped sexually exhausted rats resume mating, an effect comparable to the drug yohimbine. In a follow-up study (Journal of Ethnopharmacology 2013), 10 mg per kg shortened ejaculation latency much as 10 mg per kg of sildenafil did, and both effects were blocked by L-NAME, a drug that stops the body making nitric oxide, suggesting that damiana acts mainly through nitric oxide signaling in the brain and spinal cord. The same dose reduced anxiety-like behavior. No study has measured these mechanisms in people, and Tyler’s older suggestion, that irritation of the urinary passages was mistaken for arousal, has never been tested either.

In the laboratory, damiana compounds touch hormones and brain chemistry. Zhao and colleagues (Journal of Ethnopharmacology 2008) found that a leaf extract blocked aromatase, the enzyme that turns testosterone into estrogen, with an IC50 (the concentration that blocks half the enzyme’s activity) of 63.1 micrograms per ml; its flavonoids pinocembrin and acacetin were the most potent of 24 compounds tested, while apigenin 7-glucoside and two others showed weak estrogen-like activity in a yeast test. Zava and colleagues (Proceedings of the Society for Experimental Biology and Medicine 1998) ranked damiana among the six commonly consumed herbs that bound most strongly to progesterone receptors in breast cancer cells, and found such extracts generally neutral or blocking rather than progesterone-like. Memorial Sloan Kettering Cancer Center (MSKCC) concludes that whether damiana is estrogenic is unclear. Chaurasiya and colleagues (Molecules 2019) found that acacetin 7-methyl ether from damiana selectively inhibited monoamine oxidase B, an enzyme that breaks down dopamine. In mice, water and methanol extracts reduced anxiety-like behavior (Kumar and Sharma, Journal of Herbal Pharmacotherapy 2005) and also depression-like behavior (Ana María and colleagues, Journal of Ethnopharmacology 2019), and Szewczyk and Zidorn identify apigenin as the pain-relieving principle in animal experiments.

Blood sugar and drug-handling results are mixed or preliminary. Alarcon-Aguilar and colleagues (Journal of Ethnopharmacology 1998) found that damiana, prepared the traditional way, was one of eight out of 28 Mexican diabetes remedies that blunted blood sugar spikes in rabbits, but in mice the same group’s water-ethanol extract had no blood sugar-lowering effect (Phytotherapy Research 2002). Parra-Naranjo and colleagues (Molecules 2017) isolated a terpenoid, teuhetenone A, that gradually lowered glucose in normal and diabetic mice, while a 2023 review by the same group cites rat studies with no effect. On drug metabolism, Husain and colleagues (Journal of Ethnopharmacology 2023) screened 123 medicinal plant extracts and placed damiana leaf among the potent activators of the pregnane X receptor (PXR), a switch that can induce drug-metabolizing enzymes, and among the strong inhibitors of CYP3A4, a major drug-processing enzyme. Taha and colleagues (Journal of Ethnopharmacology 2012) attributed damiana’s stomach-protecting effect in rats to arbutin, which they call a major constituent. All of this is cell or animal work; none has been confirmed in people.

Low sexual desire in women is where the human evidence is most often cited, and it belongs to a blend. Ito and colleagues (Journal of Sex and Marital Therapy 2001) gave 77 women ArginMax for Women or placebo for four weeks, and 73.5% on the supplement versus 37.2% on placebo reported more satisfaction with their overall sex life; one co-author worked for the Daily Wellness Company, which makes ArginMax. In a second four-week trial in 108 women with low desire (Ito and colleagues, 2006), desire improved in premenopausal and postmenopausal women (51% versus 8% after menopause). But Greven and colleagues (Journal of Community and Supportive Oncology 2015), funded by the US National Cancer Institute and the Daily Wellness Company, found no difference in desire, arousal, lubrication, orgasm, satisfaction, or pain after 12 weeks in 186 cancer survivors, although quality-of-life scores were better. A systematic review by Cieri-Hutcherson and colleagues (Pharmacy 2021) notes that ArginMax is 77% L-arginine and that damiana could make up at most 612 mg of the daily dose. The only damiana-only study, by Rotmann and colleagues (Zeitschrift für Phytotherapie 2021), gave 675 mg of leaf extract daily for eight weeks; scores on the Female Sexual Function Index rose and distress fell in 35 women, but there was no control group, and two co-authors worked for Dr. Loges, a German herbal medicine maker. Verdict: plausible enough to study, unproven for damiana itself.

Erectile dysfunction and male sexual function rest on rat studies and one product trial. Shah and colleagues (BMC Complementary and Alternative Medicine 2012) randomized 78 men aged 25 to 50 with mild to moderate erectile dysfunction (ED) to VigRX Plus or placebo for 12 weeks; erectile function scores rose from 16.1 to 25.1 on the product and from 15.9 to 16.5 on placebo. Each capsule contained 100 mg of damiana leaf among about a dozen ingredients, including Asian ginseng, saw palmetto, ginkgo, hawthorn, and tribulus; the manufacturer, Leading Edge Herbals, funded the trial, and the investigators were paid for their work. We found no randomized trial of damiana alone in men. Verdict: unproven, and a doctor can offer ED treatments with known effects and check for the heart disease and diabetes that ED can signal.

Weight loss and appetite were studied with YGD, a capsule of yerba mate, guarana, and damiana. Andersen and Fogh (Journal of Human Nutrition and Dietetics 2001) found that YGD slowed stomach emptying in seven volunteers (58 versus 38 minutes) and that, in a 45-day double-blind trial in 47 overweight patients taking three capsules before each main meal, weight fell by 5.1 kg on YGD versus 0.3 kg on placebo; 22 patients who stayed on it for a year kept their weight steady. Harrold and colleagues (Appetite 2013) found that three YGD tablets taken before meals cut energy intake at lunch by 112 kcal (17.3%) in 58 women. Yerba mate and guarana are both caffeine-containing plants, and these studies cannot show what, if anything, damiana adds. Verdict: one positive trial of a blend, too old and small to rely on.

Menopause symptoms, mood, and anxiety have only blend or animal data. Yakoot and colleagues (Forschende Komplementärmedizin 2011) randomized 120 women with menopausal symptoms to Lady 4, a capsule of evening primrose oil, damiana, ginseng, and royal jelly, or placebo; 86.7% versus 56.7% rated themselves much or very much improved. Palacios and colleagues (BMC Women’s Health 2019) reported better sexual function scores in 29 postmenopausal women taking Libicare, a tablet of fenugreek, damiana, tribulus, and ginkgo, but the study had no control group and one author was employed by the maker. For anxiety and depression, MSKCC notes that the calming effects seen in mice have not been studied in people. Verdict: traditional use, not established.

Blood sugar, digestion, and other traditional uses lack human studies. MSKCC lists diabetes, anxiety, constipation, kidney disorders, and menstrual disorders among the purported uses of damiana and reports no data to support constipation, kidney, or menstrual claims; blood sugar effects come from animal studies with conflicting results. Szewczyk and Zidorn observe that most of the genus’s reported bioactivities have been tested only in chemical, cell, or animal assays. The 2023 review by Parra-Naranjo and colleagues (Pharmaceuticals) describes hepatoprotective, antioxidant, and anti-inflammatory activity in laboratory and animal models, none of it in patients. Verdict: none of these uses is established, and diabetes in particular needs proven treatment. For desire problems, our libido guide compares herbs with more human evidence, such as ginseng and maca.

Traditional preparations are simple. In Mexico, dried leaves and flowering tops are steeped as a tea, often sweetened, and the Baja California Sur ranchers studied by Pío-León and colleagues drink damiana tea as an everyday social beverage as well as a remedy. Piacente and colleagues analyzed exactly this kind of infusion and found flavonoids and arbutin in it. Damiana also flavors liqueurs and is steeped in tequila or mezcal (Juárez-Aragón and colleagues), and homeopathic preparations exist. We found no agreed dose for damiana tea: the traditional use has not been measured, and the strength of a cup depends on how much leaf is used and how long it steeps. The liqueur adds alcohol, which carries its own effects on sleep, mood, and sexual function.

The doses used in research are product-specific. The German traditional herbal medicine Remisens contains 225 mg per tablet of a dry leaf extract (5 to 7 parts leaf to 1 part extract, made with 90% ethanol); its leaflet recommends one tablet three times a day after meals for adults, 675 mg in total, the same daily amount studied for eight weeks by Rotmann and colleagues, and does not recommend it under 18. ArginMax was taken as three caplets twice a day, and Cieri-Hutcherson and colleagues calculate that its 2,700 mg proprietary blend of L-arginine, ginseng, ginkgo, and damiana could contain at most 612 mg of any one herb. VigRX Plus provided 100 mg of damiana per capsule, two capsules twice a day. YGD was taken as three capsules before each main meal, and the trial abstract does not state the damiana content. Rodent studies used 10 to 80 mg of extract per kg of body weight, which cannot be translated directly into a human dose.

Quality and labeling vary. In the United States, damiana is sold as a dietary supplement, which does not need FDA approval before sale, and federal food rules (21 CFR 172.510) list “damiana leaves, Turnera diffusa” among natural flavoring substances that may be used in food, with no restriction to alcoholic drinks. Damiana itself is caffeine-free, according to Pauli and colleagues, but many “energy” and weight-loss blends add guarana or yerba mate. Products sold for sexual enhancement are a particular risk: FDA warns that many such products, including some sold as dietary supplements or all-natural treatments, are likely to be contaminated with dangerous hidden ingredients, and that its public list covers only a small fraction of them. Reassuringly, Jiménez-Amezcua and colleagues (Journal of Chromatography A 2026), employees of a Spanish botanical extract company, found no sildenafil, tadalafil, vardenafil, or avanafil in 20 damiana supplements. In the “Spice” smoking mixtures analyzed by Ogata and colleagues, most plants identified by DNA did not match the labels, a reminder that recreational products are not what they claim.