L-Arginine

Your intake

What each level of l-arginine does

Approximate dose-response bands. Individual response varies — these are starting points, not prescriptions.

1. Severely lowYOU ARE HERE

   0 g – 0.99 g

   Well below target. Risk of deficiency symptoms tied to nitric oxide.

2. Insufficient

   0.99 g – 3 g

   Below the recommended daily target. Long-term adequacy not assured.

3. Adequate

   3 g – 4.5 g

   Daily target met. Standard nutritional support for nitric oxide.

4. Therapeutic

   4.5 g – 6 g

   Common for specific health goals. Check the evidence for your situation before sustaining this level.

5. Diminishing returns

   6 g – +

   Past the point where extra intake typically helps. Evidence for further benefit is thin.

Close the gap

You're at 0% of your l-arginine target. The biggest single-serving sources to top it off:

Overview

Conditionally essential amino acid, precursor to nitric oxide (NO) via NO synthase, and to creatine, urea, and polyamines. Adequate endogenous synthesis in healthy adults; conditional essentiality in trauma, burns, and certain disease states.

Functions

• ●Substrate for NO synthase → nitric oxide (vasodilation, immune signalling)
• ●Substrate for urea cycle (ammonia detoxification)
• ●Precursor for creatine synthesis (with glycine and methionine)
• ●Precursor for polyamines (cell proliferation)
• ●Substrate for proline → collagen synthesis

Mechanism

Endothelial NO synthase converts L-arginine + O2 to L-citrulline + NO. NO diffuses into vascular smooth muscle, activates guanylate cyclase, raises cGMP, and triggers vasodilation. Pharmacologic effect is limited because arginase competes for arginine; this is why citrulline (which bypasses gut arginase first-pass) often outperforms arginine for NO support.

Benefits

• ●Improves erectile function in mild-to-moderate ED
• ●Improves exercise capacity in heart failure (some trials)
• ●Reduces preeclampsia risk in some pregnancy trials
• ●May accelerate wound healing in surgical and trauma patients
• ●Bodybuilder marketing for 'pump' is weakly supported — citrulline is better

Deficiency

Frank deficiency is rare in adults. Conditional deficiency in trauma, sepsis, burns, and inherited urea cycle defects.

Excess

Well-tolerated to ~9 g/day. GI distress is the typical limit. Post-MI use of high-dose arginine in one trial (VINTAGE-MI) increased mortality — caution in recent CV events.

Forms

• L-arginine HCl
  Standard oral form; affordable; mild stomach upset common at gram doses
• L-arginine alpha-ketoglutarate (AAKG)
  Marketed for bodybuilding; thin evidence vs plain arginine
• Citrulline (precursor)
  Often a better arginine-raising strategy than arginine itself

Food sources

• Pumpkin seeds · 1 oz1.4 g
• Cooked turkey · 3 oz2 g
• Cooked chicken breast · 3 oz1.9 g
• Cooked salmon · 3 oz1.5 g
• Lentils (cooked) · 1 cup1.3 g
• Peanuts · 1 oz0.9 g

Supplement forms

L-arginine HCl or arginine alpha-ketoglutarate at 3–6 g/day. For NO support in healthy adults, citrulline often outperforms arginine on a per-gram basis. Don't combine with PDE-5 inhibitors (Viagra, Cialis) without medical supervision — additive hypotension.

Bioavailability

~70% oral absorption but ~40% is degraded by intestinal arginase before reaching circulation. Citrulline bypasses this first-pass and is converted to arginine renally — a more reliable plasma arginine route at most doses.

Longevity relevance

NO signalling supports endothelial function — vascular health is central to healthspan. Adequate arginine intake from food is typically sufficient; supplementation has small CV benefits in some populations but no clean longevity signal.

Relationships

References

• Examine — Argininereview
• VINTAGE-MI trial — arginine and post-MI mortality (JAMA 2006)study

About L-Arginine

Nitric oxide precursor; vasodilation, blood flow. Common dose 3–6 g/day.

Role

Nitric oxide

Daily target

3 g (TR)

Also called

l-arginine, arginine