L-Arginine in Memodyne: What 400 mg Can and Cannot Do
Quick answerL-arginine is an amino acid the body uses to make nitric oxide, which relaxes blood vessels. Each Memodyne capsule lists 400 mg in two forms. Blood pressure trials used 4 to 24 g a day, and one small memory trial used 3.3 g a day. Arginine can add to blood pressure drugs, nitrates and ED pills, so ask a doctor first.
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01 of 7- Where it is named
- Printed with its own amount on the Supplement Facts panel
- Amount per capsule
- 400 mg (200 mg base + 200 mg AKG 2:1)
- Doses used in studies
- 1.66 g twice a day in a small memory trial; 4-24 g a day in blood pressure trials (Mone et al., 2022)
- Share of the studied dose
- About 12% of the 3.3 g memory-trial dose
- Also called
- Free-form arginine
What is L-arginine?
L-arginine is an amino acid, one of the building blocks of protein. Your body makes some of it, and food supplies the rest. Meat, fish, dairy, eggs, nuts and beans are all good sources.
Doctors call it conditionally essential. Healthy adults usually make enough, but needs can rise during illness or injury. In supplements, it is sold mainly for blood flow and workouts. In Memodyne, it is the largest line on the label.
How does arginine become nitric oxide?
This is why arginine shows up in nitric oxide products. Wider vessels can mean lower blood pressure (Dong et al., 2011). The brain depends on steady blood flow, which is the idea behind putting arginine in a cognitive formula.
An idea is not proof, though. Our how it works page walks through what is known and what is not.
Why does Memodyne use two forms of arginine?
| Label line | Printed | What it is | Note |
|---|---|---|---|
| L-Arginine (base) | 200 mg | Free arginine | All of the weight is arginine |
| L-Arginine AKG 2:1 Extract | 200 mg | Arginine joined to alpha-ketoglutarate | Part of the weight is the AKG carrier |
The base form is plain arginine. The AKG form joins arginine to alpha-ketoglutarate, a compound the body uses to make energy. Sports products like the AKG form, and one study gave trained men 12 g a day of it (Campbell et al., 2006).
The label does not say why both forms are used. Together they add up to 400 mg of printed weight per capsule. See the Supplement Facts page for how carrier weight works.
What doses of arginine have been studied?
- 400 mgPrinted in one Memodyne capsule
- 3.3 gDaily dose in the memory trial
- 4-24 gDaily range in blood pressure trials
| Study | Who took part | Dose | What was found | Source |
|---|---|---|---|---|
| Dong et al., 2011 | 11 trials, 387 people | 4 to 24 g a day | Systolic about 5 mmHg and diastolic about 3 mmHg lower than placebo | (Dong et al., 2011) |
| Mone et al., 2022 | 72 frail older adults with high blood pressure | 1.66 g twice a day for 4 weeks | Thinking-test scores differed from placebo | (Mone et al., 2022) |
| Campbell et al., 2006 | Trained adult men | 12 g a day of arginine AKG for 8 weeks | Some strength and power measures improved | (Campbell et al., 2006) |
| VINTAGE MI, 2006 | People after a heart attack | Daily arginine for 6 months | No benefit and more deaths in the arginine group | (Schulman et al., JAMA 2006) |
Every study dose is many times larger than one capsule. The memory trial dose is about eight times larger. The blood pressure trials used 10 to 60 times more.
Honest note: what did the arginine memory trial find?
The trial most often linked to arginine and memory is small (Mone et al., 2022). It enrolled 72 frail older adults who had high blood pressure and thinking problems. One group took 1.66 g of L-arginine twice a day. The other took a placebo.
After four weeks, thinking-test scores in the arginine group differed from the placebo group. That is an interesting signal. It is not strong proof.
What the trial did well
- A placebo group was used for comparison
- It was done in older adults, the group most worried about memory
- It measured thinking with a standard test
Why it is not enough
- Only 72 people took part
- It lasted four weeks
- It was single-blind, not double-blind
- The dose was about eight times what Memodyne lists
- Everyone had high blood pressure and frailty, unlike most buyers
No review shows arginine improves memory in healthy people, and no study of Memodyne exists. Our article on arginine and memory research goes deeper.
Can L-arginine lower blood pressure?
Yes, at gram doses it can, by a small amount. Across 11 trials, 4 to 24 g a day lowered systolic pressure by about 5 mmHg (Dong et al., 2011). A later review found modest drops in some trials and mixed results overall (Khalaf et al., 2019).
Whether 400 mg changes blood pressure is unknown. It may do little on its own. Still, the effect points the same way as blood pressure medicine, and that is why the drug warnings matter.
Which medicines can interact with L-arginine?
Blood pressure drugs
Arginine may add to these and push pressure too low. Watch for dizziness or fainting.
Nitrates
Nitroglycerin and other nitrates also work through nitric oxide. Combined with arginine, pressure might drop too far.
ED pills
ED pills, for example sildenafil or tadalafil, relax blood vessels too. Ask before mixing them with arginine.
Mayo Clinic warns that arginine with nitroglycerin, sildenafil or blood pressure drugs might make blood pressure drop too low (Mayo Clinic, L-arginine). Memorial Sloan Kettering says the same about blood pressure medicine (MSKCC, Arginine).
Bring the Memodyne label to your pharmacist if you take any of them. Our post on nitric oxide supplements and blood pressure pills has a checklist.
What did the VINTAGE MI trial find after heart attacks?
After a heart attack, ask first
VINTAGE MI gave arginine or placebo for six months to people who had just had a heart attack (Schulman et al., JAMA 2006). Arginine did not improve the heart or the arteries. More deaths occurred in the arginine group, and the trial was stopped early.
If you have had a heart attack, ask your cardiologist before taking any arginine product, including this one.
The trial used far more arginine than one capsule, and it does not prove arginine caused the deaths. But it is the main reason heart patients should not add arginine on their own (MSKCC, Arginine). The side effects page lists other warning signs.
When is the best time to take the arginine in Memodyne?
The label says one capsule daily with 8 oz of water, 20 to 30 minutes before a meal. Breakfast is an easy meal to tie it to. There is no need to take it before exercise. The how to use page has more habit tips.
When should memory changes go to a doctor instead?
Some forgetfulness is normal with age. Memory loss that gets in the way of daily life needs a doctor's visit (NIA, Memory problems and aging). Some causes can be treated, such as low vitamin B12 or a medicine side effect.
Getting lost in a familiar place or new trouble with words are signs to book a visit (Alzheimer's Association, 10 warning signs). Sudden confusion, trouble speaking or numbness on one side can be a stroke. Call 911 and note the time (CDC, Stroke signs).
L-arginine FAQ: questions people ask
Does L-arginine help memory?
It has not been shown to help memory in healthy people. One small 4-week trial in frail older adults with high blood pressure used 3.3 g a day and found different thinking-test scores than placebo, but it was single-blind and short.
What does L-arginine do in the brain?
Arginine is a raw material for nitric oxide, which helps blood vessels relax, including those that feed the brain. Whether a supplement changes brain blood flow enough to matter is not settled.
How much L-arginine is in Memodyne?
One capsule lists 400 mg: 200 mg of plain L-arginine and 200 mg of L-arginine AKG. Part of the AKG form is the carrier, so the arginine itself is a little under 400 mg.
What is the best time to take L-arginine?
For Memodyne, follow the label: one capsule daily with 8 oz of water, 20 to 30 minutes before a meal. Taking it at the same time each day makes it easier to remember.
Can I take L-arginine with blood pressure medication?
Only with your doctor's okay. Arginine may lower blood pressure, and together with blood pressure drugs it might push pressure too low.
Can you take L-arginine with Viagra?
Ask your doctor first. Sildenafil and arginine can both lower blood pressure, and Mayo Clinic warns the mix might make it drop too low.
Is L-arginine safe after a heart attack?
Ask your cardiologist before taking it. In the VINTAGE MI trial, arginine after a heart attack did not help and more deaths occurred in the arginine group, so the trial was stopped early.
What are the side effects of L-arginine?
Stomach upset, bloating and diarrhea are the most often listed, mostly at gram doses. The bigger concern is low blood pressure when it is combined with heart or blood pressure drugs.
What foods are high in L-arginine?
Meat, poultry, fish, dairy, eggs, nuts, seeds and beans all supply arginine. Most adults get some every day from food.
Ready to try Memodyne?
One capsule a day, 30 per bottle, from $49 a bottle on the 6-bottle pack, with a 60-day money-back window shown on the sales page. Take blood pressure or heart medicine? Ask your doctor first.
