🫀 Nitric Oxide (NO) Production: L-Arginine, L-Citrulline and Nitrate Pathways
How to boost nitric oxide and improve blood vessels
Nitric oxide (NO) is a signaling molecule that dilates blood vessels and improves blood flow. It is produced via L-arginine, L-citrulline and nitrates. Let's look at it in detail.
What is NO
Nitric oxide (NO) is a signaling molecule produced by the vascular endothelium. It dilates vessels (vasodilation), lowering blood pressure and improving blood flow.
- Signaling molecule.
- Dilates vessels.
- Lowers blood pressure.
- Improves blood flow.
L-arginine pathway
L-arginine is the amino acid precursor of NO. The enzyme eNOS converts arginine into nitric oxide. However, much of arginine is metabolized in the gut.
- L-arginine — precursor.
- eNOS enzyme.
- Part is metabolized.
- Needs high doses.
L-citrulline
L-citrulline is an amino acid converted into arginine in the kidneys, bypassing hepatic metabolism. Therefore it boosts NO more effectively.
- Converted to arginine.
- Bypasses the liver.
- Boosts NO more effectively.
- Better tolerated.
Nitrates
Dietary nitrates (from beets, spinach) are converted into NO via nitrite reductase. This is an eNOS-independent pathway to boost NO.
- Nitrates from vegetables.
- Converted to NO.
- Independent pathway.
- Beets and greens.
Vessels and blood pressure
NO relaxes the smooth muscle of vessels, lowering arterial pressure and improving elasticity. This matters for the heart and hypertension prevention.
- Relaxes vessels.
- Lowers blood pressure.
- Improves elasticity.
- Supports the heart.
Erection and endurance
NO is required for erection (penile vessel dilation) and athletic endurance (better blood flow to muscles). Hence its popularity among athletes.
- Erection depends on NO.
- Improves blood flow.
- Boosts endurance.
- Useful for athletes.
Food sources
| Nutrient | Food | Content |
|---|---|---|
| Nitrates | Beets | High |
| Nitrates | Spinach | High |
| L-arginine | Pumpkin seeds | ~4 g/100 g |
| L-citrulline | Watermelon | ~250 mg/100 g |
| L-arginine | Turkey | ~2 g/100 g |
Protocol
- L-citrulline: 3–6 g/day (more effective than arginine).
- L-arginine: 3–6 g/day if needed.
- Beets and spinach — dietary nitrates.
- Combine with vitamin C.
- Monitor blood pressure.
- Consult a doctor with hypotension.
What is nitric oxide?
A signaling molecule that dilates vessels and improves blood flow.
Arginine or citrulline?
L-citrulline is usually more effective as it bypasses hepatic metabolism.
How do nitrates boost NO?
Nitrates from beets convert to NO by an independent pathway.
How much citrulline?
3–6 g/day to boost NO.
Does NO lower blood pressure?
Yes, by dilating vessels, NO lowers arterial pressure.
Does it help with erection?
Yes, NO is needed for vessel dilation during erection.
Where is it found in food?
Beets, spinach (nitrates), seeds and turkey (arginine), watermelon (citrulline).
Does it help athletes?
Yes, it improves blood flow to muscles and endurance.
Is it safe with hypotension?
Be cautious — it may lower blood pressure; a doctor is needed.
When is a doctor needed?
With low blood pressure and nitrate drugs.