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

Table of Contents

• Current evidence position
• Key safety points
• Brad's videos on this topic
• Overview
• Forms and Bioavailability
• Evidence for Benefits
• Recommended Dosing
• Safety and Side Effects
• Drug Interactions
• Dietary Sources
• References

Current evidence position

Brad has not made a video on this topic; this is a summary of the evidence, not his view. Supplements sold for sexual enhancement are the largest group of products the FDA has found to contain hidden prescription drugs: from 2007 through 2016, 353 of 776 adulterated supplements in its warnings were marketed for sexual enhancement, and sildenafil was the most common hidden drug in them ^[6]. For the herbs themselves, an overview of systematic reviews drew cautiously positive conclusions for yohimbine and ginseng in erectile dysfunction and found the evidence for maca insufficient, and small trials suggest L-arginine and L-citrulline may help mild to moderate erectile dysfunction ^{[67, 53, 27]}. Yohimbe can be dangerous: high doses of yohimbine can cause heart attack, heart failure and death, and NIH advises using it only under medical supervision ^[62]. Erection problems are most often caused by artery disease, so see a doctor before trying any of these products ^[46].

Brad's videos on this topic

None yet.

1. Overview

Sexual enhancement supplements include herbal extracts such as yohimbe, horny goat weed (epimedium), tribulus terrestris, maca root and ginseng, and amino acids such as L-arginine. They are marketed to improve libido, erections and sexual performance.

The evidence for most of these ingredients is limited. An overview of systematic reviews drew cautiously positive conclusions for yohimbine and ginseng in erectile dysfunction and found the evidence for maca insufficient ^[67]. A systematic review of maca found limited evidence from a few small trials ^[2]. Yohimbine beat placebo in a meta-analysis of seven trials, but it carries cardiovascular risks ^{[5, 62]}.

The bigger problem is what the label leaves out. From 2007 through 2016, the FDA identified 776 adulterated dietary supplements; 353 (45.5%) were marketed for sexual enhancement, and sildenafil was the most common hidden drug in that group (166 of 353) ^[6]. Hidden drugs kept turning up even after FDA warnings ^[6]. A hidden PDE5 inhibitor is dangerous for anyone taking nitrate heart medicines, because the two together lower blood pressure sharply ^[66].

Lifestyle changes also have trial support. In obese men with erectile dysfunction, two years of weight loss and more exercise improved erectile function scores ^[65], and a review of exercise trials recommended about 160 minutes of aerobic exercise a week ^[46]. Persistent erection problems deserve a doctor's visit, because the leading cause is artery disease ^[46].

2. Forms and Bioavailability

These products span herbal extracts, amino acids and minerals, and the amount of active compound can differ widely from the label.

Yohimbe (Pausinystalia johimbe)

Yohimbe comes from the bark of Pausinystalia johimbe, a West African evergreen tree. Its main active compound, yohimbine, blocks alpha-2 adrenergic receptors ^[62].

Available forms:

• Yohimbe bark and bark extracts: sold alone or in combination products.
• Yohimbine: used as a drug for erectile dysfunction for longer than sildenafil (Viagra) ^[9].

Label interpretation: Labels are unreliable. In an analysis of 49 US yohimbe supplements, yohimbine per serving ranged from none detected to 12.1 mg, and only 11 listed a quantity; most of those were wrong, at 23% to 147% of the label amount ^[58]. In 19 of the 49, the other bark alkaloids were missing, which suggests highly processed extract or synthetic yohimbine ^[58].

Epimedium (Horny Goat Weed)

Epimedium is a genus of flowering plants used in traditional Chinese medicine. Several species appear in supplements, including Epimedium brevicornum and Epimedium sagittatum ^{[10, 30]}.

Active compound, icariin: In a laboratory test on the human PDE5 enzyme, the target of sildenafil, icariin was far weaker than sildenafil: its IC50 was 5.9 microM, against 74 nM for sildenafil ^[10]. Human trial evidence is very limited.

Maca Root (Lepidium meyenii)

Maca is a plant of the cabbage family that grows in the central Andes of Peru between 4,000 and 4,500 m altitude, and it is used as a food and a traditional medicine ^[11].

Available forms: Maca is sold as dried root powder, extracts and gelatinized (heat-treated) powder; the main trial in men used gelatinized maca ^[15].

Hormones: In trials, maca did not change testosterone or estradiol in men ^[15], or estradiol, FSH, LH or sex hormone-binding globulin in postmenopausal women; maca extracts also showed no meaningful estrogen-like or androgen-like activity in a laboratory test ^[33].

Ginseng (Panax genus)

Available forms:

• Panax ginseng (Asian or Korean ginseng): the species most studied for erectile dysfunction ^[16].
• Korean red ginseng: unskinned Panax ginseng that is steamed or otherwise heated and then dried ^[16].
• American ginseng (Panax quinquefolius): a related species, less studied for sexual health.

Tribulus Terrestris

Tribulus terrestris (puncture vine) is a flowering plant used in traditional medicine.

Available forms: The extract in the largest trial, Tribestan, is standardized to furostanol saponins ^[47].

Claimed mechanism: Tribulus is marketed as a testosterone booster, but in a small trial in young men it did not change testosterone, androstenedione or luteinizing hormone ^[48].

Drug interaction concern: Research suggests tribulus is a moderate inhibitor of CYP3A4, a liver enzyme that breaks down statins and many other common medicines (see Drug Interactions section) ^[41].

L-Arginine

L-arginine is an amino acid that the body uses to make nitric oxide ^[22].

Available forms: L-arginine is sold as the free amino acid or as salts. Trials in erectile dysfunction used doses ranging from 1,500 to 5,000 mg ^[53].

Bioavailability: Much of an oral L-arginine dose is broken down in the gut by the enzyme arginase. L-citrulline escapes this, is converted to L-arginine, and raised blood arginine more effectively than L-arginine itself ^[23].

Comparison Table: Sexual Enhancement Supplements at a Glance

3. Evidence for Benefits

Erectile Dysfunction — Yohimbine

Yohimbine blocks alpha-2 adrenergic receptors, which increases the release of noradrenaline ^[38].

Clinical trial evidence:

A 1998 meta-analysis of seven placebo-controlled trials found yohimbine better than placebo for erectile dysfunction (odds ratio 3.85, 95% confidence interval 6.67 to 2.22), with serious adverse reactions infrequent and reversible ^[5]. A 2001 review concluded that yohimbine alone has only modest efficacy and may work better combined with a drug that boosts the nitric oxide pathway ^[9].

A toxicology report puts the usual oral dose at 5 to 15 mg ^[38]. At much higher doses, the most common effects are raised blood pressure, mild anxiety and more frequent urination ^[9].

Yohimbine plus arginine in women: In a crossover trial in 24 postmenopausal women with sexual arousal disorder, a single dose of L-arginine glutamate (6 g) plus yohimbine hydrochloride (6 mg) increased vaginal blood flow responses to an erotic film at 60 minutes compared with placebo; the women's own ratings of arousal did not differ between treatments ^[50]. The result belongs to the combination, not to either ingredient alone.

Limitations: Yohimbine's safety profile limits its use (see Safety section).

Erectile Dysfunction — L-Arginine

Erection depends on nitric oxide, which relaxes the smooth muscle of the penis; L-arginine is the raw material the body uses to make it ^[22]. PDE5 inhibitors act on the same pathway.

Evidence in men: In a 1999 trial in 50 men with organic erectile dysfunction, 5 g a day of L-arginine for 6 weeks led 9 of 29 men (31%) to report better sexual function, against 2 of 17 on placebo; objective measures did not change, and the men who improved had low nitric oxide markers at the start ^[24]. A 2019 meta-analysis of 10 trials in 540 men with mild to moderate erectile dysfunction found that arginine supplements at 1,500 to 5,000 mg a day improved erectile dysfunction compared with placebo or no treatment (odds ratio 3.37, 95% CI 1.29 to 8.77); some trials combined arginine with other substances ^[53].

Evidence in women: In women, the trial evidence involves combination products. In a 4-week trial in 77 women, ArginMax for Women (L-arginine with ginseng, ginkgo, damiana, vitamins and minerals) improved satisfaction with overall sex life in 73.5%, against 37.2% on placebo; the result cannot be credited to L-arginine alone ^[68].

L-arginine plus sildenafil: Combining the two might lower blood pressure too far, so check with your doctor first ^[55].

L-citrulline as an alternative: L-citrulline raises blood arginine more effectively than L-arginine ^[23]. In a single-blind study, 24 men with mild erectile dysfunction took placebo for 1 month and then 1.5 g a day of L-citrulline for 1 month; erection hardness became normal in 12 (50%) on L-citrulline, against 2 (8.3%) on placebo ^[27].

Brad's position: Brad does not recommend L-arginine or L-citrulline supplements (Brad's current guidance, 9 Aug 2026).

Erectile Dysfunction — Ginseng

Korean red ginseng is the form most studied for erectile dysfunction ^[16].

Cochrane review: A Cochrane review of nine placebo-controlled trials found that ginseng appears to have a trivial effect on erectile function scores (mean difference 3.52, 95% CI 1.79 to 5.25; low certainty) and may improve men's self-reported ability to have intercourse (RR 2.55, 95% CI 1.76 to 3.69) ^[28].

Earlier evidence: A 2008 systematic review of red ginseng pooled six placebo-controlled trials (risk ratio 2.40, 95% CI of 1.65, 3.51) but rated their quality low ^[16]. Trials used 900 mg three times daily for 8 weeks ^[51] or 1,000 mg three times daily ^[29]; in the second, 20 men (66.6%) in the ginseng group reported better erections ^[29].

Synthesis: Ginseng may offer a small benefit for erectile function, but the trials are small and of low quality ^{[16, 28]}.

Erectile Dysfunction — Horny Goat Weed (Epimedium)

Icariin, the main marker compound in epimedium, inhibits PDE5 in laboratory tests ^[10]. This has led to its marketing as a "natural Viagra."

Reality of the evidence: Human trial evidence for horny goat weed in erectile dysfunction is very limited, and in the laboratory icariin was far weaker than sildenafil ^[10].

Animal studies: In rats given an extract of Epimedium sagittatum for 3 days, blood levels of sildenafil fell, and the authors advised against combining the two ^[30]. If this happens in people, horny goat weed could weaken sildenafil rather than boost it.

Optimal doses: No dose has been established in human trials.

Erectile Dysfunction — Tribulus Terrestris

Tribulus terrestris is marketed as a testosterone booster and sexual enhancer, with roots in Ayurvedic and traditional Chinese medicine.

Trials in men: In a 12-week trial in 180 men with mild or moderate erectile dysfunction, Tribestan (250 mg tablets, taken as 3×2 tablets daily after meals) improved erectile function scores more than placebo (difference 2.70, 95% CI 1.40, 4.01), with no difference in side effects ^[47].

Testosterone claims: In a 4-week trial in 21 healthy young men, tribulus extract at 20 and 10 mg/kg body weight per day did not change testosterone, androstenedione or luteinizing hormone ^[48].

Women with hypoactive sexual desire disorder: In a 4-week trial in premenopausal women with low sexual desire, tribulus extract improved desire, arousal and overall sexual function scores more than placebo, with similar side effects ^[49].

Libido Enhancement — Maca Root

Maca has some evidence for increasing sexual desire, but the trials are few and small ^[2].

Systematic review: A 2010 systematic review found four randomized trials: two suggested benefit for sexual desire or dysfunction, one in cyclists found none, and one in erectile dysfunction found an effect, but the trials were too few and too small for firm conclusions ^[2].

Trial in men: In a 12-week double-blind trial in men aged 21 to 56 years, maca at 1,500 mg or 3,000 mg improved self-rated sexual desire from 8 weeks, with no change in testosterone or estradiol ^[15].

Independence from testosterone: In both men and postmenopausal women, the trials found no change in sex hormones with maca ^{[15, 33]}.

Women: In a small crossover trial in postmenopausal women, 3.5 g a day of powdered maca for 6 weeks lowered sexual dysfunction scores compared with placebo ^[33].

Mechanism: How maca might act is unknown.

Vascular Health and Erectile Function — Cocoa Flavanols

Cocoa flavanols are promoted for blood flow, but the largest study of flavonoids and erectile dysfunction found its links with other flavonoid groups, mainly from fruit ^[4].

Epidemiological evidence: In a prospective study of 25,096 men followed for 10 years, higher intakes of flavones, flavanones and anthocyanins were linked to less erectile dysfunction (for flavanones, RR = 0.89; 95% CI: 0.83, 0.95), and higher fruit intake to a 14% lower risk ^[4].

Limitations: This was an observational study, and trials of flavonoid-rich foods for erectile function are still needed ^[4].

Zinc and Sexual Function

Zinc is needed by hundreds of enzymes ^[63]. Severe and moderate zinc deficiency is associated with hypogonadism in men ^[64].

Evidence: In a small study, zinc supplements given to 9 marginally zinc-deficient older men for 3 to 6 months raised serum testosterone, and restricting zinc in 4 young men lowered it ^[64].

Practical implication: Zinc supplementation makes sense only when a deficiency is confirmed or suspected. Routine zinc supplementation in zinc-replete men is unlikely to enhance sexual function.

DHEA (Dehydroepiandrosterone)

Evidence in women: A meta-analysis of 23 randomized trials in 1188 postmenopausal women with normal adrenal function found no significant improvement in libido or sexual function, and confidence in the evidence was low ^[70]. Prasterone, the synthetic form of DHEA, is FDA-approved as a vaginal treatment for moderate to severe pain during sex due to menopause ^[72].

Evidence in men: In the DAWN trial in 110 men and 115 women aged 55 to 85, 50 mg a day of oral DHEA for 1 year did no better than placebo on sexual function scales ^[71].

Safety note: In a lupus trial, 200 mg a day of prasterone raised testosterone and, to a lesser extent, estradiol, and acne (33% vs 14%) and excess hair growth (16% vs 2%) were more common than on placebo ^[73]. If you have had a hormone-sensitive cancer, ask your doctor before taking DHEA. The DHEA article covers its safety in full.

Fenugreek (Trigonella foenum-graecum)

Fenugreek is a leguminous plant whose seed extracts have been studied for effects on testosterone and sexual function.

Evidence: In a 12-week trial in 120 healthy men aged 43 to 70 years, a fenugreek seed extract (Testofen, 600 mg a day) improved sexual function, including morning erections and frequency of sexual activity, and raised total and free testosterone compared with placebo ^[34]. Larger independent trials would help confirm this.

Summary of Evidence Quality

4. Recommended Dosing

Yohimbe / Yohimbine

No safe supplement dose is established. A toxicology report puts the usual oral dose of yohimbine at 5 to 15 mg ^[38]. NIH notes that 20 to 40 mg of yohimbine can raise blood pressure slightly, while 200 mg or more can cause serious harm, including death ^[62].

Important dosing notes:

• Supplement labels often misstate yohimbine content, so the dose you take may differ from the label ^[58].
• Use yohimbe only under medical supervision ^[62].

Epimedium (Horny Goat Weed)

No dose has been established in human trials.

Maca Root

• Dose in trials: 1,500 mg or 3,000 mg of gelatinized maca in men ^[15]; 3.5 g a day of powder in postmenopausal women ^[33]
• Duration: Effects on desire appeared from 8 weeks ^[15]

Ginseng (Panax ginseng / Korean Red Ginseng)

• Korean red ginseng dose: 900 mg three times daily for 8 weeks ^[51] or 1,000 mg three times daily ^[29] in erectile dysfunction trials
• Women: three 1 g capsules a day in menopausal women ^[52]

Tribulus Terrestris

• Dose in the main trial: 250 mg tablets of Tribestan, taken as 3×2 tablets daily after meals for 12 weeks ^[47]
• Women: extract for 4 weeks in one trial; the abstract and methods report different doses ^[49]

L-Arginine

• For erectile dysfunction: 1,500 to 5,000 mg in trials ^[53]; 5 g/day in the 1999 trial ^[24]
• Alternative: L-citrulline 1.5 g daily in one small trial ^[27]

Zinc

• Use: only to correct a deficiency your doctor has found
• Upper limit: 40 mg/day for adults; higher doses taken for weeks can block copper absorption ^[63]

Fenugreek

• Dose in the main trial: 600 mg a day of a standardized seed extract (Testofen) for 12 weeks ^[34]

General Dosing Principles

1. Allow time: effects on desire or erections took 8 to 12 weeks in trials ^{[15, 47]}
2. Do not combine multiple supplements without medical advice, because their effects on blood pressure, heart rate and drug breakdown may add up

5. Safety and Side Effects

Widespread Adulteration — The Largest Safety Concern

The biggest safety issue is what is not on the label. Products marketed for sexual enhancement made up 353 of the 776 adulterated supplements the FDA identified from 2007 through 2016, and sildenafil was the most common hidden drug in them ^[6].

Key findings from FDA warnings:

• Across all categories, 157 adulterated products (20.2%) contained more than 1 unapproved ingredient ^[6].
• Of 28 products named in repeat warnings, 19 (67.9%) contained new unapproved ingredients the second or third time ^[6].
• The authors warn that these hidden drugs can cause serious harm through misuse, overuse or interactions with other medicines and health conditions ^[6].

Why this matters: A hidden PDE5 inhibitor can be dangerous for people taking:

• Nitrates (nitroglycerin, isosorbide): PDE5 inhibitors are contraindicated with nitrates because together they lower blood pressure sharply ^[66]. Do not use sexual enhancement supplements if you take a nitrate. If you feel faint or have chest pain after combining them, call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.
• Alpha-blockers: some people develop a drop in blood pressure on standing when a PDE5 inhibitor is taken with an alpha-blocker ^[66].

Yohimbe / Yohimbine

Yohimbe can be dangerous ^[62].

Common side effects:

• Raised blood pressure, mild anxiety and more frequent urination, mainly at higher doses ^[9]
• Headache, agitation and a fast heart rate ^[62]

Serious adverse events:

• A 49-year-old man came to an emergency department with palpitations and severely raised blood pressure that did not respond to several blood pressure drugs; he had been using a herbal product containing yohimbine ^[37].
• Two deaths were attributed to acute yohimbine poisoning ^[38].
• Yohimbine has been linked with irregular heartbeat, blood pressure problems, heart attacks and seizures ^[69].
• Yohimbine doses of 200 mg or more can cause heart attack, heart failure and death ^[62]. If you have chest pain, a pounding or irregular heartbeat or a severe headache after taking yohimbe, call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.

Contraindications:

• Because yohimbe raises blood pressure and heart rate, people with high blood pressure, heart disease or anxiety disorders are likely at higher risk; use it only under medical supervision ^[62].
• Do not use yohimbe if you take a monoamine oxidase inhibitor (MAOI) or tricyclic antidepressant; it can interact with these medicines ^[69].
• Yohimbe might be unsafe in pregnancy or while breastfeeding ^[69].
• If you take prescription medicines, check with your doctor or pharmacist before starting.

Epimedium (Horny Goat Weed)

Reported adverse effects:

• A 2004 case report described a fast heart rhythm (tachyarrhythmia) and hypomania with horny goat weed ^[57].
• In rats, an epimedium extract lowered sildenafil blood levels ^[30].

Contraindications:

• Because of this case report, people with a history of mania may want to avoid it ^[57].
• Concurrent PDE5 inhibitor use (possible interference with the drug) ^[30]

L-Arginine

Common side effects:

• Nausea, stomach pain and diarrhea ^[55]
• Single doses of 3 to 6 g rarely cause side effects; most occur at single doses above 9 g ^[56]

Serious safety concerns:

• Post-myocardial infarction: In the VINTAGE MI trial, 6 participants (8.6%) given L-arginine after a heart attack died during the 6-month study, against none on placebo, and the authors concluded that L-arginine should not be recommended after a heart attack ^[54]. Do not take L-arginine after a heart attack.
• Blood pressure effects: L-arginine might lower blood pressure too far when combined with blood pressure medicines, nitrates or sildenafil ^[55].
• Diabetes medications: L-arginine might lower blood sugar in people with diabetes, so diabetes medicine doses may need adjusting ^[55].
• Blood thinners: L-arginine might increase the risk of bleeding with anticoagulant or antiplatelet medicines ^[55].
• Potassium-sparing diuretics: Do not take L-arginine with amiloride, spironolactone or triamterene; these medicines raise potassium, and the combination risks high blood potassium (hyperkalemia) ^[55].
• Allergies and asthma: L-arginine can worsen allergies or asthma, so use it with caution if you have either ^[55].

Drug interaction with PDE5 inhibitors: Check with your doctor before combining L-arginine with sildenafil, because blood pressure might drop too low ^[55].

Tribulus Terrestris

Common side effects:

• In the 12-week Tribestan trial, side effects were no more common than on placebo ^[47].

Serious safety concern, CYP3A4 inhibition:

Research suggests tribulus is a moderate inhibitor of CYP3A4, a liver enzyme that breaks down statins and many other common medicines ^[41].

Case report of rhabdomyolysis: A 71-year-old man on long-term atorvastatin developed rhabdomyolysis (muscle breakdown) with a mild rise in liver enzymes after taking tribulus; the authors point to CYP3A4 inhibition ^[41]. If you take a statin and develop muscle pain or weakness with dark urine, call your local emergency number (111 in NZ, 000 in Australia, 911 in the US, 999 in the UK) or go to the emergency department.

Ginseng

Common side effects:

• Insomnia is the most common side effect of Asian ginseng ^[61]
• Severe rash, liver damage and severe allergic reactions are uncommon ^[61]

Potential interactions:

• Asian ginseng may interfere with blood clotting ^[61]. In a small trial in healthy volunteers, American ginseng reduced warfarin's effect ^[59], while in another, Asian ginseng did not change it ^[60].
• Asian ginseng might lower blood sugar; if you have diabetes, check with your doctor first ^[61].
• Asian ginseng may worsen autoimmune disorders ^[61].

Contraindications:

• Pregnancy: some studies suggest Asian ginseng may be unsafe when taken by mouth in pregnancy, and little is known about breastfeeding ^[61].
• In a trial in menopausal women, two cases of vaginal bleeding occurred during red ginseng treatment ^[52].

Maca Root

Safety profile: The trials of maca were small and short, so its long-term safety is not well studied.

Cautions:

• Maca showed no meaningful estrogen-like activity in a laboratory test ^[33]. Even so, people with hormone-sensitive conditions such as breast cancer, uterine fibroids or endometriosis may wish to check with their doctor first.
• Limited safety data in pregnancy and breastfeeding

Special Populations

Pregnant or breastfeeding women: Most sexual enhancement supplements lack safety data in pregnancy. Asian ginseng may be unsafe in pregnancy, and yohimbe in pregnancy or while breastfeeding ^{[61, 69]}.

Individuals with cardiovascular disease: Yohimbe poses the greatest risk ^[62]. Arginine should be avoided after a heart attack ^[54]. Hidden PDE5 inhibitors are dangerous with nitrates ^[66].

Individuals with psychiatric conditions: Yohimbe can cause anxiety and agitation ^{[9, 62]}, and it must not be taken with MAOI or tricyclic antidepressants ^[69]. Horny goat weed has been linked to hypomania ^[57].

Individuals taking multiple medications: Tribulus may block CYP3A4 ^[41], arginine and yohimbine affect blood pressure, and ginseng may affect clotting ^{[55, 62, 61]}. Check with your doctor or pharmacist if you take several medicines.

6. Drug Interactions

Tribulus Terrestris — CYP3A4 Inhibition

Tribulus may be a moderate inhibitor of CYP3A4 ^[41], which could raise blood levels of medicines this enzyme breaks down:

If you take prescription medicines, check with your doctor or pharmacist before starting.

Yohimbe — Cardiovascular and Psychiatric Drug Interactions

Do not use yohimbe if you take an MAOI or tricyclic antidepressant; it can interact with these medicines ^[69]. Yohimbe raises blood pressure and heart rate ^[62], so it may work against blood pressure medicines and add to the effects of stimulants. If you take prescription medicines, check with your doctor or pharmacist before starting.

L-Arginine — Vasodilatory Drug Interactions

Epimedium — PDE5 Inhibitor Interaction

In rats, an extract of Epimedium sagittatum lowered blood levels of sildenafil ^[30]. If this happens in people, combining horny goat weed with a PDE5 inhibitor could make the drug less effective.

Ginseng — Anticoagulant Interactions

Asian ginseng may interfere with blood clotting ^[61]. American ginseng reduced warfarin's effect in a small trial in healthy volunteers ^[59], while Asian ginseng did not change warfarin's effect in another ^[60]. If you take warfarin or another blood thinner, check with your doctor before using ginseng.

Maca — Hormone-Sensitive Conditions

Maca did not change sex hormones in trials and showed no meaningful estrogen-like activity in a laboratory test ^{[15, 33]}. Its effects in hormone-sensitive conditions are not known, so check with your doctor first if you have one.

Multi-Ingredient Products — Compounded Risk

Many sexual enhancement supplements combine several of these ingredients, so they carry the interaction risks of each: tribulus may block CYP3A4 ^[41], yohimbe raises blood pressure and heart rate ^[62], and L-arginine might lower blood pressure too far with blood pressure medicines ^[55]. If you take heart or blood pressure medicines, check with your doctor first.

7. Dietary Sources

Most sexual enhancement ingredients are herbal extracts with no real dietary equivalent, but some foods support the same pathways.

Nitric Oxide Precursors (Arginine Pathway)

L-arginine comes from dietary protein. Arginine content of some common foods, per 100 g ^[74]:

Zinc-Rich Foods

Meat, fish and other seafood are the richest sources of zinc, and oysters contain more zinc per serving than any other food ^[63]. Beans, nuts and whole grains also contain zinc, but the body absorbs less of it from these foods ^[63].

Flavonoid-Rich Foods (Vascular Support)

In a large prospective study, higher intakes of flavones, flavanones and anthocyanins, and of fruit, were linked to less erectile dysfunction ^[4]:

• Berries (blueberries, strawberries, blackberries): anthocyanins
• Citrus fruits: flavanones (hesperidin, naringenin)

Maca as a Food

Maca has been cultivated in Peru for more than 2,000 years and is used as a food supplement as well as for its traditional medicinal properties ^[11].

Lifestyle Factors

Lifestyle changes have trial evidence for improving erectile function ^{[46, 65]}:

• Regular exercise: A review of exercise trials recommended 40 minutes of moderate to vigorous aerobic exercise 4 times a week, with weekly exercise of about 160 minutes for 6 months ^[46].
• Healthy weight: In obese men with erectile dysfunction, two years of weight loss and more exercise improved erectile function, with about one third of men improving ^[65].