Quick answer: Melonex lists three amino acids: L-citrulline DL-malate, L-arginine alpha-ketoglutarate and L-arginine HCl. All three feed the body's nitric oxide pathway. No amounts are published. Studies that found small blood pressure drops used several grams a day.
What we know
First, an honesty note
Honesty note: the official website names three amino acid ingredients and says they are in an "optimal dosage", but it shows no amounts. A capsule usually holds about a gram of powder or less, while most studies used several grams a day. We do not invent doses; go by the Supplement Facts on your bottle.
The three ingredients
L-Citrulline DL-malate
An amino acid the kidneys turn into L-arginine, and it raises blood arginine more reliably than arginine itself. Reviews of trials at about 3 to 6 g a day found small drops in blood pressure; citrulline malate at 6 to 8 g is mostly studied for exercise.
Citrulline and blood pressure on PubMedL-Arginine alpha-ketoglutarate (AKG)
L-arginine bound to alpha-ketoglutarate, a form common in "nitric oxide" products. The body uses arginine to make nitric oxide, which relaxes blood vessels. Most blood pressure studies used gram amounts and plain L-arginine.
L-arginine and blood pressure on PubMedL-Arginine HCl
The hydrochloride salt of the same amino acid. A meta-analysis of trials using 4 to 24 g a day found an average fall of about 5 mmHg in systolic pressure. L-arginine should not be used after a recent heart attack.
MedlinePlus on L-arginineWhy citrulline and arginine together?
Much of the arginine you swallow is broken down in the gut and liver before it reaches the blood. Citrulline avoids most of that breakdown and is converted into arginine by the kidneys, so it raises blood arginine levels more steadily. Combining them is a common approach in nitric oxide products.
Evidence at a glance
| Ingredient | Claimed role | Evidence |
|---|---|---|
| L-citrulline | Blood flow, blood pressure | Small drops in trials at 3 to 6 g a day |
| L-arginine (AKG and HCl) | Nitric oxide, blood pressure | About 5 mmHg systolic in trials at 4 to 24 g a day |
| Malate and AKG carriers | Energy metabolism | Little direct evidence at supplement doses |
Key cautions
- May add to blood pressure medicines, nitrates and ED pills.
- L-arginine should not be used after a recent heart attack.
- Arginine may trigger herpes outbreaks.
- Bloating, stomach upset and diarrhea are the most common side effects.
More on the how to use page. Deeper reading: L-arginine vs L-citrulline.
References
- MedlinePlus: L-arginine.
- PubMed: L-arginine and blood pressure, meta-analyses.
- PubMed: L-citrulline and blood pressure, meta-analyses.
- CDC: About high blood pressure.
- American Heart Association: Understanding blood pressure readings.
- NHLBI: High blood pressure.
Frequently asked questions
General information, not medical advice. Melonex is a dietary supplement and is not intended to diagnose, treat, cure or prevent any disease.