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L-Arginine Stomach Side Effects and Dose
L-arginine stomach side effects include nausea, diarrhea, bloating and belly pain, and NIH names them as the most common reactions at 9 to 30 grams a day. Melonex's two arginine lines weigh at most 333 mg a capsule, about 4% of 9 grams. Call your doctor if symptoms are severe.
Written by the Melonex numbers deskUpdated · 4 min read
01What is reported
What stomach side effects does L-arginine cause?
L-arginine stomach side effects reported by Mayo Clinic include nausea, belly pain, diarrhea and bloating.
Mayo Clinic also lists gout, headache, allergy and worse asthma among arginine's effects (Mayo Clinic, L-arginine). Drugs.com adds dyspepsia, palpitations and low blood pressure (Drugs.com, L-arginine monograph).
Those are the effects most people mean by a stomach problem.
| Area | Effects named | Source |
|---|---|---|
| Stomach and gut | Nausea, belly pain, diarrhea, bloating, dyspepsia | Mayo, Drugs.com |
| Heart and pressure | Palpitations, low blood pressure | Drugs.com |
| Other | Gout, headache, allergy, worse asthma | Mayo |
02Dose line
At what dose does arginine upset the stomach?
NIH names stomach upset as the most common reaction at 9 to 30 grams of arginine a day.
The same NIH sheet says up to 9 grams a day for days or weeks is safe and well tolerated. It adds that safety of high doses beyond 3 months is unknown (NIH ODS, Supplements for Exercise).
So the trouble zone starts around where the safe zone ends. Individual tolerance varies, and a smaller dose can still bother some people.
One capsule holds at most 333 mg across both arginine lines (21 CFR 101.36 (proprietary blends)). Two capsules hold at most 667 mg. Both are well under 9 grams.
- 1 capsule: 333 mg is about 4% of 9 g.
- 2 capsules: 667 mg is about 7% of 9 g.
- Against 30 g, the figures are about 1% and 2%.
03The blend
Which Melonex lines could affect the stomach?
Two lines of the Melonex blend are arginine salts: the AKG line and the HCl line.
The citrulline line can bother the stomach too, and a separate post covers it. Here, only the arginine pair matters.
Line two is the alpha-ketoglutarate salt and line three is the HCl salt. Together they weigh at most 333 mg, and the salt parts add weight beyond the arginine. The true arginine dose is lower again. The label prints no single amounts, so we cannot give a tighter figure.
Each box shows the ceiling for one capsule.
- Hydroxypropyl methylcellulose The vegetable capsule shell (a plant-cellulose material)
- Microcrystalline cellulose A plant-fiber filler that bulks out the powder
- Magnesium stearate A flow aid that stops powder sticking to machines
From the Supplement Facts panel. The three blend lines are listed from most to least by weight (21 CFR 101.36 (proprietary blends)), so each "≤" figure is a ceiling per capsule, not the real amount. The other ingredients are not part of the 500 mg.
04Safe habits
How can you lower the chance of an upset stomach?
Follow the label: one capsule with an 8 oz. glass of water, and go no higher than two a day.
The label says take one capsule daily with an 8 oz. glass of water and up to two a day. It also says do not exceed the recommended dose.
Start with one
Do not jump to two on day one.
Take it with water
The label calls for a full glass.
Note the time and symptoms
A short log helps your doctor see a pattern.
Call your doctor if symptoms last or feel severe. Keep taking prescribed medicine, and never stop one because of a supplement without asking first. See the how-to-take guide for more.
05Who waits
Who should check with a doctor before using arginine?
Anyone with a recent heart attack, kidney or liver disease, or who takes nitrates or blood pressure drugs should ask first.
Mayo Clinic's advice is to avoid arginine after a recent heart attack (Mayo Clinic, L-arginine). Drugs.com reports high potassium in people with liver or kidney problems (Drugs.com, L-arginine monograph). The label also asks pregnant or nursing mothers and anyone under 18 to see a physician. Read the who-should-take guide and the side effects page.
The 3- and 6-bottle packs ship free per the seller's order page. Confirm prices at checkout.
Prices listed on the seller's order page; confirm at checkout. The 2-bottle kit costs $158, with $9.99 shipping. Ask your doctor about your medicines first. 60-day money-back guarantee per the seller.
Melonex is not a treatment; it is a dietary supplement. Ask your doctor or pharmacist first if you take blood-pressure medicine, nitrates for chest pain, an erectile-dysfunction drug such as sildenafil or tadalafil, a potassium-sparing diuretic (amiloride, spironolactone, triamterene), a blood thinner, or diabetes medicine, or if you have had a recent heart attack. Arginine and citrulline can add to these. Keep taking prescribed medicine. See side effects and interactions.
06FAQ
Melonex questions people ask
Does arginine cause diarrhea?
It can at high doses. NIH names diarrhea and nausea as the most common reactions at 9 to 30 grams a day (NIH ODS, Supplements for Exercise). A Melonex capsule holds at most 333 mg of arginine salts, but anyone can react to a supplement. Report lasting symptoms to your doctor.
Can arginine cause bloating?
Yes, Mayo Clinic lists bloating with nausea, belly pain and diarrhea among arginine's side effects (Mayo Clinic, L-arginine). The sources we read tie the stomach effects to larger doses, so a small capsule is less likely, though not guaranteed.
Is it okay to take arginine on an empty stomach?
The Melonex label calls for one capsule daily with an 8 oz. glass of water and names no food rule. If your stomach feels off, ask your pharmacist whether timing could matter for you.
How long do arginine stomach effects last?
The sources we read give no duration. We cannot say how long it lasts for any one person. Call your doctor if symptoms last more than a day or two or feel severe.
07Who wrote this
Written and reviewed by
Pages built from the label, the seller's materials and linked NIH, FDA, CDC, AHA, FTC and peer-reviewed sources.
Last updated . Read how we write and how we check reviews. This website is run by Melonexheart, which describes itself as a U.S. authorized Melonex merchant. It is not the manufacturer or the label's distributor, and we cannot independently verify the 'authorized' status. We are paid when you buy through our order links.
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