Sexual Enhancement Supplements: Benefits, Forms, Dosing, and Side Effects

Sexual enhancement supplements are among the most commonly purchased dietary supplements, typically containing ingredients such as yohimbe bark, epimedium (horny goat weed), L-arginine, and tribulus terrestris. These products are marketed for erectile dysfunction, libido enhancement, and sexual performance.

Critically, the FDA has identified sexual enhancer supplements as the largest category of supplements adulterated with prescription drugs — most commonly PDE5 inhibitors such as sildenafil (Viagra) and tadalafil (Cialis) [1]. A California study found 67% of retail sexual enhancer supplements were adulterated [2].

Table of Contents

• Overview
• Forms and Bioavailability
• Evidence for Benefits
• Recommended Dosing
• Safety and Side Effects
• Drug Interactions
• Dietary Sources
• References

Overview

Sexual enhancement supplements typically contain ingredients such as yohimbe bark, epimedium (horny goat weed), L-arginine, and tribulus terrestris. The FDA has identified this category as the most commonly adulterated with undisclosed prescription drugs [1], with 67% of products in one retail study containing PDE5 inhibitors [2]. Products in blister packs were more than 8 times as likely to be adulterated as those in bottles (89% vs 10%).

Clinical evidence supporting natural sexual enhancement ingredients is generally limited, with most studies being small and short-term.

Forms and Bioavailability

Epimedium (Horny Goat Weed)

Available as dried aerial parts or extract standardized to 8–10% icariin. Raw herb powder contains only 1–3% icariin. A label listing "10% flavonoids as icariin" overestimates actual icariin content.

Yohimbe

Bark extract containing yohimbine (approximately 10–15% of total alkaloids). Extracts are typically standardized to 2–6% alkaloids. Large doses of bark are needed to achieve therapeutic yohimbine levels.

L-Arginine

An amino acid and nitric oxide precursor available as free-form powder or capsule.

Tribulus Terrestris

Available as dried fruit or extract. No established standardization protocol. Often marketed for testosterone support with limited clinical evidence.

Evidence for Benefits

Yohimbine for Erectile Dysfunction

Yohimbine is the most studied ingredient. A typical clinical dose is 5.4 mg three times daily. Higher doses are not necessarily more effective. Evidence is limited to small studies.

Arginine for Sexual Dysfunction

In men, some evidence suggests 5,000 mg/day may be effective for mild erectile dysfunction, while 1,500 mg/day is not. A small trial found yohimbine (6 mg) plus arginine (6 g) enhanced physiological sexual response in women, though yohimbine alone did not outperform placebo.

Epimedium and Tribulus

Icariin from epimedium has shown PDE5 inhibitory activity in lab studies, but robust human clinical trials are lacking. Despite widespread marketing, clinical evidence for tribulus terrestris in sexual function or testosterone enhancement is limited.

Recommended Dosing

• Yohimbine: 5.4 mg three times daily after meals
• Arginine: 5,000 mg/day for men; 2,500–6,000 mg/day in women's studies
• Epimedium: 500–1,000 mg/day of extract standardized to 10% icariin
• Tribulus terrestris: No established optimal dose

Safety and Side Effects

Adulteration Risk

The most serious concern is adulteration with undisclosed prescription drugs. Consumers taking nitrates or cardiovascular medications could experience dangerous interactions from hidden PDE5 inhibitors [2].

Yohimbe

Common side effects: increased blood pressure, anxiety, increased urination. Blood pressure increases begin at ~20 mg yohimbine [3]. Hospitalization has been reported with severe hypertension [4]. One death has been linked to yohimbe [5]. Other effects: rash, nausea, rapid heartbeat, atrial fibrillation, confusion.

Arginine

Generally safe with occasional mild stomach upset. May worsen reflux. Should not be taken after acute myocardial infarction [6].

Tribulus Terrestris

Inhibits CYP3A4 enzyme, which metabolizes ~50% of all drugs [8]. One case of rhabdomyolysis with atorvastatin reported [9].

Drug Interactions

• PDE5 inhibitors (Viagra, Cialis): Arginine may cause excessive blood pressure drops. Epimedium may decrease effectiveness [7].
• Statins: Tribulus inhibits CYP3A4, increasing statin levels and rhabdomyolysis risk (particularly lovastatin, simvastatin, atorvastatin) [8][9].
• Blood pressure medications: Yohimbe may increase blood pressure. Arginine may lower it.
• Anticoagulants: Tribulus may affect apixaban and rivaroxaban levels via CYP3A4.
• Diabetes medications: Arginine may improve insulin response, risking hypoglycemia.

Dietary Sources

Arginine is found in meat, poultry, fish, dairy, nuts, seeds, and legumes. Yohimbe, epimedium, and tribulus are not dietary foods and are consumed only as supplements.

References

1. Tucker J et al., JAMA Netw Open, 2018.

2. Fischer BD et al., Nutr Diet Suppl, 2023.

3. Tam SW et al., Pharmacol Ther, 2001.

4. Prescott AT et al., J Emerg Med, 2019.

5. Anderson C et al., J Anal Toxicol, 2013.

6. Wallace AW et al., Anesth Analg, 2000.

7. Hsueh TY et al., Molecules, 2013.

8. Wang Z et al., Front Pharmacol, 2022.

9. Huff JS et al., Am J Case Rep, 2024.