Clinical Trials: Herbs That Improve Erectile Function

This review summarizes human clinical evidence for selected herbs and nutraceuticals that have improved erectile function in randomized trials. It uses validated outcomes (e.g., IIEF) and links to peer-reviewed sources.

How “improvement” is measured

• IIEF (International Index of Erectile Function) domain scores are the standard outcome in ED trials.
• Most studies run for 4–12 weeks and compare an herb or blend against placebo.

Evidence by ingredient

Panax ginseng

• Cochrane-style systematic review (2021) found low-to-moderate quality evidence that ginseng improves erectile function versus placebo in RCTs.
• World Journal of Men's Health summary reports positive effects on intercourse ability; certainty graded low due to small samples and heterogeneity.

L-arginine (alone or in combos)

• Meta-analysis (2019): evidence that oral L-arginine improves mild-to-moderate ED vs placebo.
• Network/meta-analysis (2021): L-arginine and PDE5 inhibitors can be effective alone; some combinations show added benefit.
• L-arginine + Pycnogenol combo improved sexual function in mild–moderate ED.
• 3-month RCT (2022) showed endothelial and sexual-function benefits with high-dose L-arginine.

Tribulus terrestris

• Systematic review/meta-analysis (2025): several RCTs report improved erectile function; study quality varies.
• Placebo-controlled RCT (2017) showed significant sexual-function gains with standardized extract.
• Systematic review (2025): doses ~400–750 mg/day for 1–3 months improved ED in part of the trials evaluated.

Antioxidant formulations

• Meta-analysis (2024) across double-blind RCTs found antioxidants improved erectile function vs placebo; effects larger in more severe ED. Long-term data limited.

What this means for shoppers

• Some herbs have clinical signals for ED, especially Panax ginseng, L-arginine (solo or with Pycnogenol), and Tribulus terrestris.
• Expect incremental gains, typically measured over 4–12 weeks. Not all trials are large or long.
• Formulas differ. Standardization, dose, and combinations matter.

Where Erectimus fits

• Learn how the formula supports circulation and performance: How Erectimus Works.
• Ingredient background on Maca and related botanicals: Maca Root for Men’s Performance.
• Product page: Erectimus Single Pack.

Safety, interactions, and limitations

• Trials often exclude men with complex comorbidities or polypharmacy. Real-world results can vary.
• Check for interactions (e.g., antihypertensives, anticoagulants). Discuss supplements with a clinician if you have cardiovascular disease or take prescription meds.
• Evidence quality ranges from low to moderate for many botanicals due to small samples, short durations, and heterogeneous extracts.

Typical timelines and dosing seen in studies

• Panax ginseng: 1.5–3 g/day for 4–12 weeks in RCTs (review).
• L-arginine: 1.5–5 g/day, 4–12 weeks; combos with Pycnogenol show added benefit (meta-analysis, combo RCTs).
• Tribulus terrestris: ~400–750 mg/day for 1–3 months in RCTs and reviews (systematic review).
• Antioxidant blends: 4–24 weeks across trials; effects vary by composition (meta-analysis).

Quick FAQ

Do herbs work as fast as prescription ED drugs?

Generally no. Trials measure changes over weeks. Some users report quicker subjective effects, but RCT outcomes are typically assessed after sustained use.

Can I use herbs with PDE5 inhibitors?

Some data suggest combinations may help, but this should be managed by a clinician due to potential blood-pressure effects (analysis).

What has the strongest evidence right now?

Among botanicals, Panax ginseng and Tribulus terrestris show supportive but still limited RCT evidence. L-arginine has multiple meta-analyses with positive signals, especially in combinations.

Selected references

• Lee HW et al. Ginseng for Erectile Dysfunction: Cochrane-style Review (2021).
• Rhim HC et al. L-arginine Meta-analysis (2019).
• Xu Z et al. L-arginine vs PDE5Is and combos (2021).
• Suharyani S et al. Tribulus terrestris Meta-analysis (2025).
• Kamenov Z et al. Tribulus RCT (2017).
• Ramasamy R et al. Antioxidant Supplementation Meta-analysis (2024).
• Frontiers Endocrinology. L-arginine + Pycnogenol (2023).

Next step

• Read the mechanism overview: How Erectimus Works.
• If you want to try a plant-based option, start here: Erectimus Single Pack.