Blog
L-Citrulline Side Effects: Usually Mild, With Exceptions
L-citrulline side effects were mild in short-term studies: researchers saw no gastrointestinal effects even at a single 15 g dose, while high doses of arginine caused nausea and diarrhea. That evidence is short and small. Long-term use is less studied, and citrulline still becomes arginine in the body, so drug cautions apply.
Written by the Melonex label deskUpdated · 4 min read
What are the side effects of L-citrulline?
The side effects of L-citrulline were few in short-term studies. A review reported it was well tolerated, with no gastrointestinal effects even at 15 g (Aguayo 2021, L-citrulline review).
High doses of arginine, by comparison, caused nausea, vomiting or diarrhea (Aguayo 2021, L-citrulline review). That gap is one reason people compare the two.
| Amino acid | Dose in studies | Stomach effects |
|---|---|---|
| L-citrulline | Single 15 g dose | None reported |
| L-arginine | High doses | Nausea, vomiting, diarrhea |
How reliable is the safety evidence for citrulline?
The safety evidence is short and narrow. The studies behind it lasted days to weeks, so months or years of daily use are less known.
Absence of reported effects is not proof of safety for every person. Melonex has no safety study of its own.
- Short studies, mostly healthy adults
- No trial of the Melonex blend
- Pregnancy and children are not covered
Does L-citrulline interact with medicines?
L-citrulline can matter for medicines because the kidneys turn about 83% of it into arginine (Aguayo 2021, L-citrulline review). Arginine may add to blood pressure drugs, nitrates and sildenafil and push pressure too low (Mayo Clinic, L-arginine).
Ask your doctor or pharmacist first if you use those drugs. Keep taking prescribed medicine as directed.
Melonex: from $49 a bottle60 capsules · 2, 3 or 6 bottles · free US shipping on 3 or 6 · 60-day guarantee
See packsWhat does that mean for Melonex capsules?
For Melonex, the citrulline line is the biggest part of a 500 mg blend, but it also holds two arginine forms. So the arginine cautions apply to the whole capsule.
The label asks pregnant or nursing mothers, anyone under 18 and people with a medical condition to consult a physician first. Dizziness or fainting can mean low blood pressure, which is below 90/60 (NHLBI, low blood pressure).
If you feel faint, sit down and call a clinician. Chest pain needs 911.
Where can you order Melonex?
If your doctor agrees, these are the two packs with free US shipping.
Free US shipping3 bottles · $207$69 a bottle · 180 days at 1 capsule a day · free US shippingChoose 3 bottles
Lowest per bottle6 bottles · $294$49 a bottle · 360 days at 1 capsule a day · free US shippingChoose 6 bottlesSales-page prices, October 18, 2026 (Melonex sales page). A 2-bottle pack is also sold ($158 plus $9.99 shipping). See every pack on the pricing page.
FDA disclaimer. These statements have not been evaluated by the Food and Drug Administration. Melonex is not intended to diagnose, treat, cure, or prevent any disease. Keep taking prescribed medicine, and ask your doctor before starting any supplement.
FAQ01
Melonex questions people ask
Can L-citrulline cause diarrhea?
Short studies reported no stomach effects even at 15 g (Aguayo 2021, L-citrulline review). Individual reactions vary, so stop and ask a clinician if you get any.
Is L-citrulline safe to take every day?
Studies are short, so long-term safety is less known. A Melonex capsule holds a small amount, and the label asks people with a medical condition to consult a physician.
Is L-citrulline safer than L-arginine?
It was better tolerated at high doses in short studies (Aguayo 2021, L-citrulline review). It still converts to arginine, so the drug cautions are similar.
Who wrote this02
Written and reviewed by
Pages built from the label, the sales page and linked NIH, FDA, AHA, CDC, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a USA authorized Melonex retailer, not by the manufacturer or the distributor. We earn money when you buy through our order links.
Keep reading
More about Melonex
USA authorized Melonex retailer
Ready to try Melonex?
Check your medicines first, then pick a pack. Three or six bottles ship free in the US and cost less per bottle, and the 60-day guarantee opens after 30 days of use.
- Secure checkout
- 60-day guarantee
- Ships from the U.S.