Ingredient guide

What Are the Ingredients in Melonex?

Quick answer

Melonex ingredients are three amino acid forms in a 500 mg blend: L-citrulline DL-malate, L-arginine alpha-ketoglutarate and L-arginine HCl. Three inactive parts make the capsule: hydroxypropyl methylcellulose, microcrystalline cellulose and magnesium stearate. The label hides single amounts, and no trial has tested the product.

Written by the Melonexcare editorsUpdated October 19, 2026

No. 01The list

What are the Melonex ingredients?

The Melonex ingredients list has six lines: three amino acid forms in a 500 mg proprietary blend, and three inactive ingredients that make the capsule.

The blend comes first on the label. In order, it is L-citrulline DL-malate, L-arginine (alpha-ketoglutarate dihydrate) and L-arginine HCL.

After the blend, the label lists "other ingredients": hydroxypropyl methylcellulose, which is the capsule shell, microcrystalline cellulose and magnesium stearate.

Nothing else is named. There are no herbs, vitamins or minerals on this label, and no melon extract despite the name.

1L-Citrulline DL-MalateBlend place 1 · at most 500 mg per capsule
2L-Arginine (Alpha-Ketoglutarate dihydrate)Blend place 2 · at most 250 mg per capsule
3L-Arginine HCLBlend place 3 · at most 167 mg per capsule
4Hydroxypropyl Methylcellulose (capsule)Other ingredient · no amount listed
5Microcrystalline CelluloseOther ingredient · no amount listed
6Magnesium StearateOther ingredient · no amount listed

From the Supplement Facts panel. Places 1-3 are the 500 mg blend, listed from most to least by weight (21 CFR 101.36). The other three lines make the capsule and help it fill; they carry no listed amount.

No. 02In plain words

What is in the Melonex formula, in plain words?

The Melonex formula is two amino acids, citrulline and arginine, each paired with a partner molecule so it can be sold as a stable powder.

Your body makes both amino acids and gets some from food. It can turn citrulline into arginine, and it uses arginine to make nitric oxide, a gas that helps blood vessels relax.

The partner parts are malate, alpha-ketoglutarate and hydrochloride. They are not extra active ingredients. They are the other half of each salt, and they add to the weight on the label.

No. 03Profiles

Where can you read about each Melonex ingredient?

Each ingredient has its own page with the studies, the cautions and the label's wording.

Pick the line you care about most. Every profile says what the ingredient is, how much the capsule can hold and what researchers have tested.

No. 04Blend math

How much of each Melonex ingredient is in a capsule?

The label does not print single amounts, but its order gives ceilings: at most 500 mg, 250 mg and 167 mg per capsule.

A blend may show just its total, provided the names run from the most to the least by weight (21 CFR 101.36). So the first can be up to the whole 500 mg, the second up to half, and the third up to a third.

Those three ceilings cannot all be reached at once, since the blend only weighs 500 mg. If all three were equal, each would be about 167 mg. At the label's top of two capsules a day, the ceilings double.

L-Citrulline DL-Malate
Even 2 capsules reach at most 33% of the lowest trial dose

1 capsule, even split167 mg
1 capsule, label-order ceiling (place 1)500 mg
2 capsules (label max), ceiling1,000 mg
3-9 g a day of L-citrulline (8 trials)3-9 g
Not printed: #1 of 3 in a 500 mg blend. The weight is the salt form, so the free amino acid is less. (Barkhidarian 2019, citrulline and BP) (21 CFR 101.36)
L-Arginine AKG
Even 2 capsules reach at most 12% of the lowest trial dose

1 capsule, even split167 mg
1 capsule, label-order ceiling (place 2)250 mg
2 capsules (label max), ceiling500 mg
4-24 g a day of L-arginine (11 trials)4-24 g
Not printed: #2 of 3 in a 500 mg blend. The weight is the salt form, so the free amino acid is less. (Dong 2011, arginine and BP) (21 CFR 101.36)
L-Arginine HCl
Even 2 capsules reach at most 8% of the lowest trial dose

1 capsule, even split167 mg
1 capsule, label-order ceiling (place 3)167 mg
2 capsules (label max), ceiling333 mg
4-24 g a day of L-arginine (11 trials)4-24 g
Not printed: #3 of 3 in a 500 mg blend. The weight is the salt form, so the free amino acid is less. (Dong 2011, arginine and BP) (21 CFR 101.36)

Burgundy bars: what capsules can hold, on one scale with the trial doses. The label prints only the 500 mg total, so we show an even split (about 167 mg each) and the most the label order allows (500, 250 and 167 mg; double at 2 capsules). Green bars: daily grams of the amino acid alone in blood pressure trials; the pale extension shows the range. No trial tested Melonex.

The bars compare the capsule with the grams used in studies. The capsule is the smaller number by a wide margin. A salt weight also overstates the amino acid inside it.

No. 05The studies

What do studies of these heart health supplement ingredients show?

Trials of citrulline and arginine, at grams a day, went with small drops in blood pressure. None tested Melonex.

When people search for heart health supplement ingredients, these two amino acids come up often. The research is real but modest, and it is worth reading with the doses beside it.

Research on the amino acids in Melonex, as reported in the past tense
Amino acid	Studies	Dose used	What was found
L-citrulline	8 small trials (Barkhidarian 2019, citrulline and BP)	3-9 g a day, 1-17 weeks	Systolic pressure about 4.10 mm Hg lower on average; diastolic change was not significant
L-arginine	11 trials, 387 people (Dong 2011, arginine and BP)	4-24 g a day	Systolic about 5.39 and diastolic about 2.66 mm Hg lower than placebo
Alpha-ketoglutarate	Reference review (RxList, alpha-ketoglutarate)	No oral dose established	Evidence is not enough for oral uses

One capsule holds a few hundred milligrams at most. The trials used 3,000 mg or more of the free amino acid. The gap is large, and that is why we do not tell you to expect those results.

Melonex: from $49 a bottle60 capsules a bottle · 2, 3 or 6 bottles · 60-day money-back

See packs

No. 06Cautions

Are there cautions with the Melonex ingredients?

Yes. Arginine and citrulline can push blood pressure too low with some medicines, and arginine is not advised after a recent heart attack.

What I would want you to know before the first capsule is short. Do not combine citrulline with nitrates or with sildenafil-type drugs (RxList, L-citrulline). Arginine can also add to blood pressure drugs and nitrates (Mayo Clinic, L-arginine).

Potassium-sparing diuretics are another flag, since arginine may raise potassium (Mayo Clinic, L-arginine). Blood thinners matter too, because arginine may raise the risk of bleeding.

In a trial of 153 people after a first heart attack, 6 died on arginine at 9 g a day, against none on placebo, and the trial was stopped early (VINTAGE MI trial (ACC summary)). That dose is far above one capsule, yet it explains why doctors are careful.

Keep taking prescribed medicine

Never stop or change a medicine because you began a supplement. Show the bottle to your pharmacist first.

No. 07Inactive parts

What are the other ingredients in Melonex?

The other ingredients are hydroxypropyl methylcellulose, microcrystalline cellulose and magnesium stearate. They hold, fill and flow the powder.

The capsule shell is a plant cellulose, so the capsules are vegetable capsules. The cellulose filler bulks the powder. Magnesium stearate keeps it moving through the filling machine.

They have no job as nutrients. If you react to cellulose or stearate, ask your pharmacist. See the other ingredients profile.

No. 08Next steps

What should you check before buying Melonex?

Read the label against your own medicine list, then decide whether the amounts suit your goal.

Take the bottle or its photo to your pharmacist and ask about each medicine you take. Read the full panel on the supplement facts page, and see pricing if you decide to order.