NutriStack
L-Arginine and Tadalafil, a caution.
Same mechanism as sildenafil + L-arginine. Tadalafil has a 36-hour half-life, making the interaction window much longer than sildenafil.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- L-Arginine and Tadalafil
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 4 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Same mechanism as sildenafil + L-arginine. Tadalafil has a 36-hour half-life, making the interaction window much longer than sildenafil.
Mechanism. L-arginine increases NO production. Tadalafil inhibits PDE5 (with 36hr half-life). Prolonged amplification of NO/cGMP pathway causes sustained vasodilation.
Recommendation. Use caution. Tadalafil's long duration means the vasodilatory interaction persists for 1-2 days. Start L-arginine at low doses.
Sources (4)
- Stanislavov R, Nikolova V. Treatment of erectile dysfunction with pycnogenol and L-arginine. J Sex Marital Ther. 2003;29(3):207-213. PMID 12851125
- Viribay A, Burgos J, Fernández-Landa J, Seco-Calvo J, Mielgo-Ayuso J. Effects of Arginine Supplementation on Athletic Performance Based on Energy Metabolism: A Systematic Review and Meta-Analysis. Nutrients. 2020. PMID 32370176
- Rezaei S, Gholamalizadeh M, Tabrizi R et al.. The effect of L-arginine supplementation on maximal oxygen uptake: A systematic review and meta-analysis. Physiological Reports. 2021. PMID 33587327
- Hadi A, Arab A, Moradi S et al.. The effect of l-arginine supplementation on lipid profile: a systematic review and meta-analysis of randomised controlled trials. British Journal of Nutrition. 2019. PMID 31922465
Stack Score
How this pair moves the number.
Effect on the composite score
If both L-Arginine and Tadalafil are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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