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Nitric Oxide Supplements: What They Can and Cannot Do
Nitric oxide supplements are products that supply amino acids, mainly L-arginine and L-citrulline, which the body uses to make nitric oxide. They do not contain the gas. Melonex belongs to this group with a 500 mg blend of three forms, while trials of the same amino acids used grams a day.
Written by the Melonex label deskUpdated · 4 min read
What are nitric oxide supplements?
Nitric oxide supplements are capsules or powders with ingredients the body can turn into nitric oxide, a short-lived gas that vessel walls release. The usual ingredients are L-arginine and L-citrulline.
Arginine is the raw material for the enzymes that make nitric oxide (Cziraki 2020, arginine-NO pathway).
- Step 1
Arginine arrives from protein or a capsule.
- Step 2
Nitric oxide synthase turns it into nitric oxide and citrulline.
- Step 3
Nitric oxide raises cGMP and vessel muscle relaxes (Cziraki 2020, arginine-NO pathway).
Why is citrulline in so many of them?
Citrulline is in these products because it raises blood arginine more effectively than arginine itself does (Aguayo 2021, L-citrulline review). The kidneys convert about 83% of it into arginine, so more arrives in the blood.
Melonex has citrulline malate as line 1 and two arginine salts after it.
What can they do, and what can they not?
Nitric oxide supplements can, at studied doses, lower blood pressure a little in trials. They cannot treat high blood pressure, and no trial has tested Melonex.
| Ingredient | Trial dose a day | Result | Melonex per capsule |
|---|---|---|---|
| L-arginine (Dong 2011, arginine meta-analysis) | 4 to 24 g | About 5.4/2.7 mm Hg lower | At most 333 mg |
| L-citrulline (Barkhidarian 2019, citrulline meta-analysis) | 3 to 9 g | About 4.1 mm Hg lower systolic | 167 to 500 mg |
Two capsules reach one gram of blend, far below every studied dose.
Melonex: from $49 a bottle60 capsules · 2, 3 or 6 bottles · free US shipping on 3 or 6 · 60-day guarantee
See packsWho should skip nitric oxide supplements?
People on nitrates, sildenafil or blood pressure drugs should ask first, since pressure may drop too low. Arginine is not recommended after a recent heart attack.
A supplement never replaces it. See the nitric oxide basics guide and the side effects page.
Which packs does Melonex come in?
The two larger Melonex packs are below.
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
Do nitric oxide supplements contain nitric oxide?
No. Nitric oxide is a gas the body makes, so supplements supply building blocks such as arginine and citrulline instead. Melonex lists citrulline malate and two arginine salts, with no nitric oxide on the label.
Is the arginine paradox a problem for these products?
It is a puzzle: extra arginine can improve vessel widening even though the enzyme seems to have enough already (Cziraki 2020, arginine-NO pathway). Trials, not theory, decide what a dose does.
Are beet nitrate products the same thing?
No. Beet products supply nitrate, a different route. Those trials are separate from the arginine and citrulline ones. Melonex has no beet.
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.
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