L-Arginine
Also known as: arginine, L-arginine base, L-arginine HCl
A conditionally essential amino acid and the direct substrate for nitric-oxide synthase. It was the original pump ingredient and remains common in heart, circulation, and men's formulas. Oral arginine has poor bioavailability because much of it is cleared by the gut and liver, so citrulline has largely replaced it for performance use, but the research base on blood flow is still substantial.
Research summary
Substrate for nitric-oxide synthase, supporting vasodilation; also a precursor for creatine, polyamines, and urea-cycle intermediates.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 1.5 g | 3–6 g | 12 g | — |
Performance trials fall into two patterns: a single acute dose of around 0.15 g/kg (about 10 g) 60–90 minutes pre-exercise, or chronic daily dosing of 1.5–2 g for several weeks. Consumer products typically use 3–6 g. Doses above about 10 g in one sitting are associated with GI upset. Arginine HCl contains about 83% arginine by mass; dose the free base or adjust accordingly.
Source material: fermentation-derived
Forms of Arginine
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| L-Arginine | 3–6 g | — | Powder, Capsule, Tablet | low |
| Arginine Alpha-Ketoglutarate (AAKG) | 3–6 g | — | Powder, Capsule, Tablet | low |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Gram-scale dose; capsule counts run high (3 g is about 4–5 size-00 capsules). Free base is alkaline and bitter; the HCl salt tastes better and is more stable in powders.
Formulation notes
Often combined with citrulline, and with pycnogenol in some circulation formulas. Arginine competes with lysine for absorption, which matters in lysine-focused products.
Sources
Related ingredients
L-Citrulline
Sports performanceA non-protein amino acid that the kidneys convert to arginine, raising plasma arginine more efficiently than oral arginine itself.
Typical: 6–8 g
Nitrosigine (Inositol-Stabilized Arginine Silicate)
Sports performanceNitrosigine is a patented complex of L-arginine bound with silicate and stabilized by inositol, developed by Nutrition21.
Typical: 1,500 mg
Beet Root Extract (Standardized Nitrate)
BotanicalA concentrated beet root extract standardized to a declared nitrate content so that a nitric-oxide dose can be delivered in a capsule or small scoop instead of gram-level powder.
Typical: 300–500 mg
Beta-Alanine
Sports performanceA non-essential amino acid that combines with histidine to form carnosine, the main intramuscular buffer of hydrogen ions during intense exercise.
Typical: 3.2–6.4 g
BCAA 2:1:1 (Leucine, Isoleucine, Valine)
Sports performanceA blend of the three branched-chain amino acids, most often at a 2:1:1 ratio of leucine to isoleucine to valine, that has been a staple of intra-workout drinks for decades.
Typical: 5–10 g