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L-Arginine HCl vs L-Arginine: Salt Weight Explained
L-arginine HCl vs L-arginine is a salt versus the plain amino acid. The hydrochloride salt carries a chloride partner, so roughly 82.7% of its weight is arginine (our arithmetic from standard molecular weights). Melonex's third line, L-Arginine HCL, can weigh at most 167 mg, which holds about 138 mg of arginine.
Written by the Melonex numbers deskUpdated · 4 min read
01Salt vs base
What is the difference between arginine HCl and L-arginine?
L-arginine HCl is arginine bonded to hydrochloric acid, which gives a salt that weighs more than the arginine alone.
Plain L-arginine is the amino acid. The HCl form adds a chloride and a hydrogen. That extra mass counts on the scale but is not arginine.
The standard molecular weights are about 174.2 for arginine and 210.7 for the HCl salt. Divide the first by the second and you get 82.7%. This is our arithmetic, not a figure from a Melonex document.
So a salt weight overstates the arginine by about a fifth. The same habit applies to every salt on a label: ask what the active part weighs, not what the powder weighs. The label walkthrough shows where each weight sits.
| Arginine HCl | Arginine inside |
|---|---|
| 167 mg | 138 mg |
| 333 mg | 275 mg |
| 1,000 mg | 827 mg |
| 4,837 mg | 4,000 mg |
02On the label
Where does arginine HCl sit on the Melonex label?
Arginine HCl is the third and last line of the 500 mg Melonex blend, so it can weigh at most 167 mg a capsule.
Blend items go in order of weight (21 CFR 101.36 (proprietary blends)). Place three holds at most one third of 500 mg, which is 167 mg. At that ceiling it carries up to 138 mg of arginine.
Because line three is last, it may be much lighter. The label gives no single number. Add lines two and three and the arginine pair tops out at 333 mg of salt, as the capsule breakdown shows.
The bars show each line against the gram doses from research.
L-citrulline DL-malate
≤500 mgplace 1 of 3One capsule's ceiling is 17% of the low end of the studied dose. (Avicenna J Phytomed 2019, L-citrulline and BP meta-analysis)
Both arginine lines together
≤333 mglines 2 and 3 togetherOne capsule's ceiling is 8% of the low end of the studied dose. (Am Heart J 2011, L-arginine and BP meta-analysis)
L-arginine AKG
≤250 mgplace 2 of 3One capsule's ceiling is 8% of the low end of the studied dose. (J Int Soc Sports Nutr 2012, AAKG)
Coral bars: the most one capsule (and the 2-capsule label maximum) can hold, from the label order (21 CFR 101.36 (proprietary blends)). Real amounts are not printed and are likely lower. Teal bars: daily amounts used in studies; the pale extension shows a range. The weights on the label include the malate, alpha-ketoglutarate and HCl parts, so the pure amino acid is less again.
03The research
Which arginine form did blood pressure trials use?
Pooled blood pressure trials used oral L-arginine at 4 to 24 grams a day, counted as the amino acid.
Eleven trials with 387 people saw systolic pressure fall by 5.39 mm Hg and diastolic by 2.66 mm Hg (Am Heart J 2011, L-arginine and BP meta-analysis). The summary names L-arginine, not a salt.
To reach 4 g of pure arginine from the HCl form, you would need about 4.8 g of the salt. A capsule's third line is at most 167 mg.
Plain L-arginine
Trial doses are written as the amino acid. Compare like with like.
HCl or AKG salt
Salt weights run higher than the arginine inside. Multiply down before you compare.
04Cautions
Does the arginine salt form change the cautions?
No source we read says the HCl form changes the cautions, which come from arginine itself.
Mayo Clinic lists arginine interactions with blood pressure drugs, nitrates, ED drugs, blood thinners and diabetes drugs. It says not to combine it with potassium-sparing diuretics, since blood potassium can rise (Mayo Clinic, L-arginine).
Anyone pregnant or nursing, under 18 or with a known medical condition is asked by the label to consult a physician first.
Keep taking prescribed medicine and tell your doctor about every supplement.
05Bottom line
What should the HCl line tell a buyer?
It tells a buyer that label weights are salt weights, and that the pure arginine is lower than it looks.
Run the same check on line two. Our post on AAKG covers its extra weight, and the arginine HCl page has the profile table.
The 3- and 6-bottle packs ship free per the seller's order page, with a 20% restocking fee on refunds. Confirm 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
Is arginine HCl stronger than L-arginine?
No. The HCl form is a heavier salt, not a stronger one. Roughly 82.7% of its weight is arginine by our arithmetic, so it holds less arginine per milligram. Neither form is shown to be better for blood pressure.
Why do supplements use arginine HCl?
Makers often choose salts for handling and stability, but Melonex does not say why. We found no maker statement. All we can say is that the label lists the HCl form last in its blend.
How much arginine is in 167 mg of arginine HCl?
About 138 mg. Arginine is roughly 82.7% of the salt by weight, from standard molecular weights. That is our arithmetic. The label prints no ratio and no single weight, so the real line may be lighter.
Does arginine HCl raise potassium?
Mayo Clinic warns that arginine can raise blood potassium and should not be combined with potassium-sparing diuretics such as spironolactone (Mayo Clinic, L-arginine). Ask your doctor or pharmacist if you take one.
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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