L-Arginine in Memodyne: 200 mg Beside the Grams Studies Used
Quick answer
L-arginine is an amino acid the body partly turns into nitric oxide, which relaxes blood vessels. Memodyne lists 200 mg of the base form plus a 200 mg arginine AKG line, so under 400 mg in all. Studies used 2 to 24 g a day for blood pressure, exercise and erectile dysfunction. None we found shows a memory benefit.
What is L-arginine, and why is it in Memodyne?
L-arginine is one of the amino acids your body uses to build protein. Your body makes some, food supplies more, and supplements deliver larger amounts than a normal diet (Memorial Sloan Kettering, Arginine (About Herbs)).
Memodyne prints it twice. One line is L-arginine (base) at 200 mg. A second line, L-arginine AKG 2:1, adds 200 mg of a bound form. The brand picks it for one reason: it calls arginine the molecule that dilates blood vessels in the brain. That is a sales page line, not a finding we could match to any source.
What is nitric oxide, in plain words?
A tiny gas molecule your blood vessels use as a relax signal. When the vessel lining releases it, the muscle in the vessel wall loosens, the tube widens and blood flows more easily.
The NIH puts the arginine link carefully: some arginine is converted to nitric oxide, a potent vasodilator that can increase blood flow (NIH ODS, Dietary Supplements for Exercise and Athletic Performance (health professional)). Follow one capsule along that path:
- 1
Capsule swallowed
Under 400 mg of arginine across the two label lines.
- 2
Some becomes nitric oxide
Only part of it; the NIH sheet gives no share.
- 3
Vessels widen
Mayo Clinic calls L-arginine a vasodilator (Mayo Clinic, L-arginine).
- 4
Blood pressure can dip
Seen in some research on healthy people, at gram doses.
- 5
Memory?
No source we opened follows the path this far.
For the longer version, read our nitric oxide explainer.
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How much L-arginine did studies use?
Grams, not milligrams. The smallest daily amount in the sources we opened is 2 g, five times the full 400 mg of both Memodyne arginine lines.
| What was studied | Daily L-arginine | How long | Source |
|---|---|---|---|
| High blood pressure | 4 to 24 g | 2 to 24 weeks | (RxList, L-Arginine (supplement monograph)) |
| Erectile dysfunction | 5 g | Lower doses might not work | (RxList, L-Arginine (supplement monograph)) |
| Chest pain (angina) | 3 to 6 g, three times a day | Up to one month | (RxList, L-Arginine (supplement monograph)) |
| Exercise performance | 2 to 20 g | Usually 4 to 8 weeks | (NIH ODS, Dietary Supplements for Exercise and Athletic Performance (health professional)) |
| After a heart attack (VINTAGE MI) | About 9 g | 6 months | (JAMA 2006, Schulman et al., L-arginine after heart attack (VINTAGE MI)) |
| One Memodyne capsule | Under 400 mg, two lines | Daily, per the label | Label |
Put another way, 400 mg is one-tenth of the 4 g starting point for blood pressure and one-fifth of the 2 g low end in exercise work. The real arginine figure is lower still, because part of the AKG line is not arginine.
Is L-arginine good for memory or the brain?
No source we opened shows it. RxList is the only one that mentions memory, saying early research suggests arginine might help memory loss related to aging, and it rates that use Insufficient Evidence to Rate (RxList, L-Arginine (supplement monograph)).
Mayo Clinic, Memorial Sloan Kettering, WebMD and the NIH exercise sheet do not list memory or thinking as a use. People also search whether arginine crosses the blood-brain barrier; none of our sources addresses that, so we cannot answer it either way.
The wider picture: the Global Council on Brain Health found that no supplement is supported for preventing, slowing or reversing cognitive decline (Global Council on Brain Health (AARP), The Real Deal on Brain Health Supplements). Losing things often, missing appointments or confusion about time, people or places calls for a doctor, not a capsule (NIA, Forgetfulness: Knowing When to Ask for Help).
What did L-arginine studies find for blood pressure, exercise and erectile dysfunction?
Small or mixed results, at gram doses. Here is what each source says, in short.
Blood pressure
Oral L-arginine lowered blood pressure in some research on healthy people (Mayo Clinic, L-arginine). WebMD calls the gains small, maybe too small to manage a condition (WebMD, L-Arginine).
Exercise
Doses of 2 to 20 g a day had little to no effect on performance (NIH ODS, Dietary Supplements for Exercise and Athletic Performance (health professional)).
Erectile dysfunction
It might help when the cause is physical (Mayo Clinic, L-arginine). Studies used 5 g a day (RxList, L-Arginine (supplement monograph)).
None of those findings carries over to focus or clarity, and none was measured at 200 mg.
Can you take L-arginine with blood pressure medicine, nitrates or Viagra?
Only after a doctor or pharmacist says so. Arginine can lower blood pressure, and stacked on these medicines the drop may go too far (Mayo Clinic, L-arginine). The sources give no safe cut-off for small amounts.
| Medicine group | What can happen | Source |
|---|---|---|
| Nitrates (nitroglycerin, isosorbide) | Blood pressure too low; more dizziness | (Mayo Clinic, L-arginine) (RxList, L-Arginine (supplement monograph)) |
| Sildenafil and other PDE5 pills | Blood pressure too low | (Mayo Clinic, L-arginine) (WebMD, L-Arginine) |
| Blood pressure medicines | Added lowering; RxList rates it Major | (Memorial Sloan Kettering, Arginine (About Herbs)) (RxList, L-Arginine (supplement monograph)) |
| Diabetes medicines | Blood sugar may fall too low | (Mayo Clinic, L-arginine) (RxList, L-Arginine (supplement monograph)) |
| Blood thinners, spironolactone-type diuretics | Bleeding risk; high potassium | (Mayo Clinic, L-arginine) |
Should you check before taking an arginine product?
Do you take a nitrate such as nitroglycerin or isosorbide?
Do you take sildenafil, tadalafil or another erectile dysfunction pill?
Do you take medicine for blood pressure or diabetes?
Have you had a recent heart attack?
Do you get cold sores or herpes outbreaks?
Are you pregnant, nursing or under 18?
Answer every question to see your result. Nothing is saved or sent.
No yes answers. The label still says one capsule a day, and nothing here means arginine helps memory.
Show the label and your medicine list to a doctor or pharmacist before the first capsule.
Sources advise against L-arginine after a heart attack. Skip it and ask your cardiologist.
Why is L-arginine not advised after a heart attack?
Because the one randomized trial in that group saw more deaths on arginine. VINTAGE MI added L-arginine or a placebo to standard care after a heart attack, aiming for 3 g three times a day for six months (JAMA 2006, Schulman et al., L-arginine after heart attack (VINTAGE MI)).
Arginine did not improve the heart's pumping or vessel stiffness, and the authors said it should not be recommended after a heart attack. Mayo Clinic says the same (Mayo Clinic, L-arginine). The trial used about 9 g a day, far more than a capsule; no source sets a safe lower amount.
Can L-arginine make cold sores worse?
One drug-information source raises the concern. RxList says there is some evidence the herpes virus needs L-arginine to multiply, so arginine might make herpes worse (RxList, L-Arginine (supplement monograph)). Mayo Clinic, Memorial Sloan Kettering and WebMD do not mention it.
Common side effects in the sources are nausea, stomach pain, bloating and diarrhea (Mayo Clinic, L-arginine). The label adds its own rule: pregnant or nursing women and anyone under 18 should ask a physician first. Our side effects page covers the whole capsule.
L-arginine in Memodyne: questions and answers
How much L-arginine is in Memodyne?
200 mg of L-arginine base plus a 200 mg L-arginine AKG line. Part of the AKG line is alpha-ketoglutarate, so the total arginine is under 400 mg.
Is L-arginine good for memory?
Not on the evidence we found. RxList rates age-related memory loss as Insufficient Evidence to Rate, and no other source we opened lists memory as a use.
Does L-arginine raise nitric oxide?
Some of it is converted to nitric oxide, a gas that relaxes blood vessels, according to the NIH. The share is not given.
Is L-arginine safe alongside blood pressure medication?
Talk to your doctor first. Mayo Clinic and RxList warn that the combination may push blood pressure too low.
Can I take L-arginine with Viagra?
Not without medical advice. Mayo Clinic and WebMD list sildenafil and other PDE5 pills as interactions that can drop blood pressure too far.
Is L-arginine safe after a heart attack?
Sources advise against it. In the VINTAGE MI trial, 6 of the arginine group died and none on placebo.
How much L-arginine lowers blood pressure?
Studies used 4 to 24 g a day for 2 to 24 weeks, per RxList. That is ten or more times a full capsule.
Is L-arginine the same as agmatine or arginine silicate?
No. Both are different compounds with similar names, and neither is on the Memodyne label.
Page check
Written by
Compares each label amount with the doses used in published research, using NIH, FDA and Alzheimer's Association pages.
Reviewed by
Dr. Harald Hampel, MD, PhD, MD, Physician
Medical reviewer. Review date: October 13, 2026.
- Last compared with the label: October 13, 2026
- Facts come from the Supplement Facts panel and the brand pages; health lines come from the sources linked above
- Corrections go to [email protected]; our checking rules are on the standards page