L-Arginine
Primary substrate for nitric oxide production — dilates blood vessels to improve circulation, exercise performance, and cardiovascular health.
L-Arginine is a semi-essential amino acid that serves as the primary substrate for nitric oxide (NO) production. Nitric oxide is a powerful vasodilator that relaxes blood vessels, improving blood flow throughout the body. This makes arginine popular for cardiovascular health, exercise performance, and erectile function. While the body can produce arginine, supplementation may benefit those with increased demands or impaired synthesis.
Substrate for NO synthase enzymes
Relaxes blood vessel walls for improved flow
May stimulate GH release
How Arginine works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
3-6g daily
Loading: Not required; can split into 2-3 doses throughout the day
Take with food
| Form | Type |
|---|---|
| 💊L-Arginine powder or capsules | Recommended |
| 💊L-Arginine HCl | Alternative |
| 💊AAKG (Arginine Alpha-Ketoglutarate) | Alternative |
Pure L-Arginine has relatively low oral bioavailability. Citrulline may be a superior choice for nitric oxide support.
Minimum: 2 weeks
Optimal: 8 weeks
Cycling: Not required
Note: Taking on an empty stomach may increase GI discomfort. Citrulline may be more effective as it converts to arginine with better bioavailability.
Better circulation and oxygen delivery
Greater blood flow to working muscles during exercise
May modestly reduce blood pressure
May cause digestive upset at higher doses
Consult healthcare provider
May trigger outbreaks; balance with lysine
May enhance hypotensive effects
May cause excessive blood pressure drop
Combined vasodilation effects
Tip: Take with food; reduce dose; try citrulline instead
Tip: Divide into smaller doses
Top studies from 40+ peer-reviewed papers
Langer G et al. • The Cochrane database of systematic reviews (2024)
“The benefits of nutritional interventions with various compositions for pressure ulcer prevention and treatment are uncertain.”
Bolarinwa AB et al. • The Cochrane database of systematic reviews (2024)
“There was inconsistent evidence on all outcomes to draw conclusions on the beneficial and harmful effects of antioxidants.”
Ye J et al. • Nutrients (2023)
“Future well-designed RCTs are needed to further confirm these findings.”
Moore ZE et al. • The Cochrane database of systematic reviews (2020)
“Evidence for the impact of nutritional interventions on the healing of foot ulcers in people with diabetes compared with no nutritional supplementation, or compared with a different dose of nutritional supplementation, remains uncertain, with eight studies showing no clear benefit or harm.”
Luo H et al. • Journal of the International Society of Sports Nutrition (2025)
“This study suggests that a range of dietary supplements, including caffeine, creatine, creatine + sodium bicarbonate, magnesium creatine chelate, carbohydrate + electrolyte, carbohydrate + protein, arginine, beta-alanine, bovine colostrum, Kaempferia parviflora, melatonin, and sodium pyruvate, can improve athletic performance in soccer players.”
What would you like to do next?
BCAAs
9/10Leucine, isoleucine, and valine metabolized directly in muscle tissue — support protein synthesis and reduce exercise fatigue.
L-Citrulline
9/10Amino acid that boosts nitric oxide production, improving blood flow, exercise performance, and recovery.
Citrulline Malate
7.5/10Combines citrulline for nitric oxide production with malic acid for ATP synthesis — reduces fatigue and enhances exercise endurance.
Creatine
9.5/10Increases phosphocreatine stores for faster ATP regeneration, boosting strength, power output, and cognitive function under stress.
Tap node to isolate • Pinch to zoom • Tap edge for research