Damiana is a plant used to make supplements or brewed as a tea mainly to increase sexual desire.
Some in vitro and animal studies have shown its ability to act as an anxiolytic (anxiety reducer), and its hypoglycemic, anti-ulcer and cytotoxic effects.
It is also used in the botanical formulation ArginMax, which is marketed for the treatment of sexual dysfunction in women. (1).
While Damiana (also known as Turnera diffusa or Turnera aphrodisiaca) has been traditionally used as an aphrodisiac in Central America and South America and other areas, clinical studies are lacking to prove its efficacy. The few studies that have been performed have been limited to animals.
Damiana acts as an aphrodisiac in rat study. A 2009 study published in the Journal of Ethnopharmacology, researchers evaluated whether Turnera diffusa recovers sexual behavior in sexually exhausted male rats and to identify the main components in an aqueous extract.
Results revealed that yohimbine and Turnera diffusa (at dosage of 80 mg/kg) significantly increased the percentage of males achieving one ejaculatory series and resuming a second one. In addition, Turnera diffusa significantly reduced the post-ejaculatory interval (3).
Researchers also discovered the presence of caffeine, arbutine and flavonoids as the main compounds in the active extract. They believe that the flavonoids present may participate in its pro-sexual effect, which are similar to those produced by yohimbine.
The aim of a 2013 study was to analyze whether the increased sexual motivation and the augmented sexual performance of sexually sluggish male rats treated with Turnera diffusa involves the nitric oxide (NO) pathway.
NO activity is thought to play a role in erectile dysfunction (4).
The results of the study showed that the aqueous extract of Turnera diffusa in rats involves the participation of NO pathway, mainly at central level. In addition, Turnera diffusa (at a dose of 10 mg/kg) facilitated expression of male sexual behavior by shortening mainly ejaculation latency. Treatments also facilitated the number of discharges in the ejaculatory motor pattern as well as the number of ejaculatory motor patterns and its associated penile erections (5).
Damiana may help treat anxiety. In an article titled, “Anti-Anxiety Activity Studies of Various Extracts of Turnera Aphrodisiaca Ward,” researchers discuss their findings on the effects of petroleum ether, chloroform, methanol and water extracts of the plant on treating anxiety. Anxiety levels were evaluated using an elevated plus-maze apparatus.
It was concluded that only methanol extract exhibited significant anti-anxiety activity at a dose of 25 mg/kg (6). Researchers determined that the presence of the bioflavonoid, apigenin is responsible for its anti-anxiety effects (7).
Damiana has gastroprotective properties. The aim of a 2012 study was to evaluate the effects of the anti-ulcerogenic activities of arbutin, a major constituent of Turnera diffusa, on two ulcer models.
Researchers analyzed the effects of arbutin on ulcer index, gastric juice acidity, mucus content and histochemistry, and gross and histological gastric lesions in aspirin or ethanol-induced ulcers in vivo. Acute toxicity of arbutin was also examined in rodent model.
Results show that pre-treatment with arbutin protected the gastric mucosa as seen by such factors as reduction in ulcer area and mucosal content and reduced or absence of edema and inflammation (8).
Based on the results, Turnera diffusa possesses anti-ulcer activity and further testing is warranted.
Damiana plays a kidney protective role in rat study. A 2017 study evaluated the antioxidant effects of water-ethanol extract from Turnera diffusa in diabetic-induced rats. The rats were orally treated during three and five weeks.
At the end of the experimental period, kidney mitochondria were isolated and malondialdehyde (a marker for oxidative stress), nitric oxide (high levels of which correlates with disease activity)and protein nitrosylation levels were measured (most effects of nitric oxide are mediated by protein nitrosylation). Blood glucose and body weight were also recorded.
Damiana significantly reduced malondialdehyde and nitric oxide levels in kidney mitochondria, although no changes in protein nitrosylation were observed and it did not have the potential to reverse the hyperglycemia (9).
Researchers concluded that Damiana has antioxidant properties that may prevent damage induced by mitochondrial oxidative stress in kidneys of diabetic-induced rats.
Damiana has potential as an anticancer therapy. The goal of a 2015 study was to evaluate the possible cytotoxic (cancer cell killing) effect of extracts and organic fractions of this plant on certain tumor cell lines —cervix, liver and breast cancer.
The results showed that methanolic extract displayed greater activity on the breast cancer cell lines. Two active compounds were isolated — arbutin and apigenin — and are what researchers believe play a role in Damiana’s cytotoxic effect (10).
In short-term studies performed on animals, Damiana appears to be safe. In one study, isolated arbutin from Damiana leaf taken for two weeks at a dosage of up to 2000mg/kg did not show any signs of toxicity.
The only common side effect of Damiana is believed to be occasional mild gastrointestinal distress.
The side effects from long-term use are not yet known and excessive doses may be dangerous.
It should not be used by children, pregnant or nursing women, or those with severe liver or kidney disease (11).
Diabetics should use Damiana with caution as it may increase the effects of hypoglycemic drugs (12).
There is currently not enough evidence to recommend an effective dosage of Damiana.
Despite the lack of scientific evidence in humans to support the efficacy of Damiana for the various conditions discussed, many continue to use it.
Traditionally, the dried leaves are brewed as a tea.
Use caution when considering Damiana. If you choose to take Damiana for sexual reasons, make sure ask your doctor first.
Damiana is a plant long used in some cultures for its libido-boosting effects. While data from studies done on mice show that it improved sexual potency, no scientific trials have been performed on humans.
In vitro and animal studies have also shown Damiana’s hypoglycemic, anti-ulcer, cytotoxic and anti-anxiety effects.
Damiana needs to be thoroughly tested on human subjects before it can be fully recommended as an efficacious and safe supplement.