Damiana

Metadata

Approved Indications

Commission E (Germany)

• Negative Monograph: Commission E reviewed damiana and concluded that the evidence was insufficient to establish efficacy for any therapeutic indication
• The negative monograph means Commission E found inadequate proof of therapeutic benefit, not that the herb was found to be dangerous
• Traditionally claimed indications that were reviewed and rejected include: aphrodisiac, treatment of sexual disorders, mental and physical exhaustion, and prophylaxis and treatment of genital conditions

ESCOP

• No ESCOP monograph has been published for damiana

EMA/HMPC (European Medicines Agency)

• No EMA/HMPC monograph exists for damiana

Agreement/Disagreement Between Bodies

• Commission E negative monograph is the only formal European regulatory assessment; it concluded evidence was insufficient
• No other European body has reviewed damiana, reflecting the limited evidence base
• The negative monograph does not prohibit sale of damiana as a supplement; it simply means it cannot be marketed with therapeutic claims in Germany based on Commission E standards
• Damiana remains widely available as a dietary supplement in the US and internationally

Conditions Treated

Primary (Traditional Claims, Very Limited Clinical Evidence)

• Sexual dysfunction / Aphrodisiac: Core traditional indication for both men and women. Mechanism may involve PDE-5 inhibition (preclinical data). Clinical evidence limited to small studies, mostly in combination products
• Low libido: Traditional Central/South American use as a sexual tonic; consumed as tea or tincture

Secondary (Traditional Use, Minimal Evidence)

• Mild depression and low mood: Traditional use as a “tonic nervine” for mild depressive states
• Nervous exhaustion / Fatigue: Traditional use for physical and mental debility
• Female sexual interest/arousal disorder: One small clinical study showed benefit with a damiana-containing product

Traditional/Historical (Limited Evidence)

• Bladder and urinary complaints (historical folk use in Mexico)
• Digestive complaints (mild bitter-aromatic digestive stimulant)
• Menstrual irregularities (historical Central American folk use)
• Diabetes (used in Mexican traditional medicine; some preclinical support)
• Weight loss (combination products with damiana, yerba mate, and guarana)
• As a flavoring in Mexican traditional liqueurs and beverages

Mechanism of Action

Primary Mechanisms

PDE-5 Inhibition (Aphrodisiac Mechanism):

• Damiana leaf extracts demonstrate dose-dependent inhibition of phosphodiesterase-5 (PDE-5) in vitro
• The PDE-5 inhibitory activity was the most potent and selective among different PDE types tested
• This mechanism is pharmacologically analogous to sildenafil (Viagra) and provides a rational basis for the traditional aphrodisiac claim
• The active compounds responsible for PDE-5 inhibition have not been definitively identified, though flavonoids (particularly pinocembrin) are candidates

Aromatase Inhibition / Hormonal:

• Flavonoids from damiana, particularly pinocembrin, have been identified as aromatase (CYP19) inhibitors
• Aromatase inhibition would reduce conversion of testosterone to estradiol, potentially increasing circulating testosterone levels
• This mechanism could contribute to libido enhancement, particularly in men
• The clinical significance of this effect at achievable oral doses has not been established

Secondary Mechanisms

Pharmacological Plausibility

• The combination of PDE-5 inhibition, aromatase inhibition, and mild anxiolytic/mood-enhancing effects provides a plausible multi-target mechanism for the traditional aphrodisiac reputation
• However, no human pharmacokinetic data exists to confirm that these effects occur at achievable plasma concentrations after oral dosing

Clinical Evidence Summary

Volume of Evidence

• Very limited. Only a handful of clinical studies exist, and most involve damiana in combination with other herbs rather than as a monotherapy. The Commission E negative monograph (1990s) was based on the absence of adequate clinical evidence at that time, and little has changed since.

Key Studies

Sexual Function

PDE-5 Inhibition

Weight Loss

What the Evidence Does NOT Show

• No clinical study has demonstrated aphrodisiac efficacy of damiana monotherapy in a placebo-controlled trial
• No study has confirmed PDE-5 inhibition in humans after oral damiana administration
• No dose-response data from human studies exists

Evidence Gaps

• No placebo-controlled RCTs for damiana monotherapy for any indication
• No human pharmacokinetic data
• No dose-response studies
• No long-term safety data from clinical trials
• No comparison with established treatments for sexual dysfunction
• The PDE-5 inhibitory mechanism has not been confirmed in vivo

European vs US/Anglophone Consensus

Safety Profile

Contraindications

• Known hypersensitivity to damiana or Passifloraceae/Turneraceae family plants
• Diabetes (potential hypoglycemic effect; monitor blood sugar)
• Liver disease (insufficient safety data; precautionary avoidance)
• Scheduled surgery (discontinue 2 weeks prior due to potential hypoglycemic effects)

Drug Interactions

• No clinically documented drug interactions
• Theoretical interaction with antidiabetic medications (damiana has shown hypoglycemic effects in animal studies)
• Theoretical interaction with PDE-5 inhibitors (sildenafil, tadalafil) if PDE-5 inhibition occurs at therapeutic doses — additive effect possible
• Theoretical interaction with anticoagulant medications (insufficient data)
• Insufficient pharmacokinetic data to assess CYP enzyme interactions

Side Effects

• Generally considered safe at standard supplement doses for short-term use
• Side effects appear to be rare at recommended doses
• Gastrointestinal irritation at high doses (uncommon)
• Headache (uncommon)
• Insomnia (possibly related to caffeine content; uncommon)
• Cyanogenic glycoside concern: Damiana contains cyanogenic glycosides (tetraphyllin B, volcalenoside) that can release hydrogen cyanide during metabolism. At normal supplement doses, the quantities are considered too low to pose a toxicity risk, but very high doses could theoretically cause cyanide-related symptoms

Pregnancy/Lactation

• Not recommended in pregnancy: Insufficient safety data; traditional use as an emmenagogue raises concerns about uterine stimulant effects
• Lactation: Insufficient data; not recommended during breastfeeding
• Not recommended for children due to lack of safety data

Clinical Dosage

Standard Dosage Forms

Historical / Traditional Doses

• In Mexican folk medicine, damiana leaf tea was traditionally consumed 1-3 times daily as a tonic
• Damiana liqueur (Licor de Damiana) is a traditional Mexican beverage; the alcohol and sugar content likely contributed to the “mood-enhancing” reputation as much as the herbal constituents

Notes on Standardization

• No universally accepted standardization exists for damiana supplements
• Products vary widely in quality and composition
• The lack of identified marker compounds for quality control is a significant limitation
• Products should ideally be tested for identity and absence of adulterants

Sources

• Commission E Monograph: Turnera diffusa (negative monograph — insufficient proof of efficacy)
• Kumar S, Sharma A. Anti-anxiety activity studies on homoeopathic formulations of Turnera aphrodisiaca Ward. Evid Based Complement Alternat Med. 2005;2(1):117-119
• Szewczyk K, Zidorn C. Ethnobotany, phytochemistry, and bioactivity of the genus Turnera (Passifloraceae) with a focus on damiana — Turnera diffusa. J Ethnopharmacol. 2014;152(3):424-443
• Zhao J, et al. Phytochemical investigation of Turnera diffusa. J Nat Prod. 2007;70(2):289-292
• Estrada-Reyes R, et al. Turnera diffusa Wild (Turneraceae) recovers sexual behavior in sexually exhausted males. J Ethnopharmacol. 2009;123(3):423-429
• Andersen T, Fogh J. Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients. J Hum Nutr Diet. 2001;14(3):243-250
• Waynberg S, Brewer S. Effects of Herbal vX on libido and sexual activity in premenopausal and postmenopausal women. Adv Ther. 2000;17(5):255-262
• Feistel B, et al. Damiana (Turnera diffusa Willd.) — a traditionally used aphrodisiac as modern PDE-5 inhibitor. Planta Med. 2010;76:P192
• Alcaraz-Melendez L, et al. Analysis of essential oils from wild and micropropagated plants of damiana (Turnera diffusa). Fitoterapia. 2004;75(7-8):696-701
• Bioactivity of the genus Turnera: a review of the last 10 years. Pharmaceuticals. 2023;16(11):1618

Connections

• Compare with Maca as a traditional Latin American herb used for libido and sexual function; maca has somewhat more clinical evidence (several RCTs) and is classified as a food in Peru
• Compare with Tongkat Ali as a traditional aphrodisiac herb with emerging evidence for testosterone support and sexual function; tongkat ali has more clinical data
• Compare with Ashwagandha as an adaptogenic herb with some evidence for sexual function and hormonal effects; ashwagandha has substantially more clinical evidence overall