Arginine / AAKG

Does it work?

• -Mostly no. Arginine and AAKG are sold as "pump" and pre-workout boosters, but the supplement-specific trials are weak. AAKG in particular failed to improve strength, endurance, or blood flow in controlled studies. Plain L-arginine has a thin, publication-bias-tainted signal for endurance at best. If you want a real pump and a measurable performance edge, citrulline does the job arginine is marketed for.

The catch

• -Oral arginine is poorly absorbed — the gut and liver break much of it down before it reaches your blood, so it raises plasma arginine and nitric oxide far less than the label implies.
• -In head-to-head AAKG trials at 3-3.7 g, it did nothing for 1RM, total volume, or blood pressure — and one chin-up study found it may actually hinder muscular endurance.
• -The positive endurance meta-analysis showed publication bias and huge variability between studies, and almost all of those trials used plain arginine, not the AAKG "pump" products on the shelf.

Better option

• -For the pump and an actual performance effect, use L-citrulline (or citrulline malate) at 6-8 g — it raises blood arginine more reliably than arginine itself.

Safety

• -Generally well tolerated, but doses above ~10 g often cause GI upset, nausea, and diarrhea.
• -Can lower blood pressure — be cautious if you take blood-pressure or erectile-dysfunction medication, and talk to a doctor first.
• -Discuss with your doctor if you have herpes (arginine may trigger outbreaks) or take any nitrate-based heart medication.

Key research

• Common Errors in Sports Nutrition Meta-Analyses Lead to Distortion of Pooled Effect Estimates. Comment on Viribay et al. Effects of Arginine Supplementation on Athletic Performance Based on Energy Metabolism: A Systematic Review and Meta-Analysis. Nutrients 2020, 12, 1300Nutrients · 2025 · Review
• Effects of Arginine Supplementation on Athletic Performance Based on Energy Metabolism: A Systematic Review and Meta-AnalysisNutrients · 2020 · Meta-analysis
• Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trialsJ Int Soc Sports Nutr · 2021 · Meta-analysis
• Acute L-arginine alpha ketoglutarate supplementation fails to improve muscular performance in resistance trained and untrained menJ Int Soc Sports Nutr · 2012 · RCT
• Pharmacokinetics, safety, and effects on exercise performance of L-arginine alpha-ketoglutarate in trained adult menNutrition · 2006 · RCT

Related