eNOS Explained: The Enzyme MemoHoney's Formula Is Built Around
Endothelial nitric oxide synthase (eNOS) is the enzyme in blood vessel lining cells that converts L-arginine into nitric oxide and citrulline. Its output depends on arginine availability, cofactors such as BH4, and mechanical shear stress from blood flow — which is why exercise is the strongest known eNOS stimulus. Supplements like MemoHoney supply substrate; they do not switch the enzyme on.
- Converts arginine → NO + citrulline
- Needs BH4, NADPH, oxygen
- Activated by shear stress
- Substrate ≠ activation
Three enzymes, one product
Humans have three nitric oxide synthase isoforms. Neuronal NOS (nNOS) makes nitric oxide as a signalling molecule in neurons. Inducible NOS (iNOS) produces large bursts during immune responses. Endothelial NOS (eNOS) sits in the cells lining blood vessels and makes the steady, low-level nitric oxide that keeps vessels relaxed. Circulation supplements target eNOS; the other two are not meaningfully affected by dietary arginine.
What the reaction needs
eNOS converts arginine plus oxygen into nitric oxide plus citrulline, consuming NADPH and requiring the cofactor tetrahydrobiopterin (BH4), plus calcium-calmodulin for activation. When BH4 is short — common in oxidative stress, diabetes and ageing — the enzyme "uncouples" and produces superoxide instead of nitric oxide. This is why arginine supplements sometimes underperform: substrate is not the bottleneck; cofactor status is.
The arginine paradox
Intracellular arginine concentrations are normally far above what eNOS needs to saturate, yet supplemental arginine still raises nitric oxide in some studies. The likely explanations involve compartmentalisation within the cell and competition from arginase. Whatever the mechanism, the paradox explains why effects are modest and inconsistent even at gram doses — and why a sub-gram dose, like MemoHoney's, should be expected to nudge rather than transform.
The stimulus that matters most
Shear stress — the frictional force of blood moving across the endothelium — is the main physiological activator of eNOS. Exercise raises shear stress, which increases eNOS expression and activity over weeks of training. This is the single most effective, best-evidenced way to raise endothelial nitric oxide, and it costs nothing. A daily walk plus a substrate supplement is a coherent combination; a substrate supplement alone is the weaker half.
What this means for MemoHoney
MemoHoney supplies eNOS substrate at a modest dose. It does not supply the cofactors or the mechanical stimulus that determine how much nitric oxide the enzyme actually makes. Pair it with movement, and keep expectations proportionate.
| Ingredient | Per capsule | Research / RDA range |
|---|---|---|
| Niacin (Vitamin B3) | 7.5 mg NE | 14–16 mg NE (RDA) |
| Calcium | 18 mg | 1,000–1,200 mg (RDA) |
| L-Arginine (base) | 200 mg | 3,000–6,000 mg |
| L-Arginine AKG 2:1 | 200 mg | 3,000–6,000 mg |
| L-Citrulline HCl | 100 mg | 3,000–8,000 mg |
| L-Citrulline Malate | 100 mg | 3,000–8,000 mg |
| Beta-Alanine | 40 mg | 2,000–6,000 mg |
Every MemoHoney amount is printed on the label — no proprietary blend. Full analysis on the ingredients page; mechanism on how it works.
Key takeaways
- eNOS output depends on cofactors and shear stress, not just arginine.
- The arginine paradox limits what substrate alone can do.
- Exercise is the strongest eNOS activator; supplements are secondary.
FAQ
Substrates like arginine and citrulline feed it; polyphenols and exercise influence its expression. No capsule 'switches it on' the way shear stress does.
When BH4 is deficient the enzyme produces superoxide instead of nitric oxide, worsening oxidative stress. It is a reason arginine supplements can disappoint in metabolic disease.
No. Folate and vitamin C support BH4 recycling; neither is on the MemoHoney label.