L-Citrulline in Memodyne: How 200 mg Fits the Formula
Quick answerL-citrulline is an amino acid the body turns into arginine, which then becomes nitric oxide. Each Memodyne capsule lists 200 mg: 100 mg as HCl and 100 mg as malate. Studies used gram doses with mixed blood pressure results. It may add to blood pressure drugs, nitrates and ED pills, so ask a doctor first.
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03 of 7- Where it is named
- Printed with its own amount on the Supplement Facts panel
- Amount per capsule
- 200 mg (100 mg HCl + 100 mg malate)
- Doses used in studies
- Gram doses in blood pressure trials (Khalaf et al., 2019)
- Share of the studied dose
- A small fraction
- Also called
- Citrulline hydrochloride
What is L-citrulline?
L-citrulline is an amino acid, but not one the body uses to build protein. Instead, it moves through the urea cycle, the process that clears extra nitrogen from the body. Your body makes it, and some foods supply it.
Its name comes from Citrullus, the Latin name for watermelon, where it was first found. In supplements, it is sold for blood flow and exercise. In Memodyne, it is the second-largest amino acid after arginine.
How does citrulline turn into arginine?
A study in healthy volunteers tested this directly (Schwedhelm et al., 2008). Oral citrulline raised blood arginine more efficiently than the same amount of oral arginine. That is why many nitric oxide products pair the two.
So the citrulline in Memodyne works as a second, slower route to arginine. Read the L-arginine page for what happens next.
Why does Memodyne use HCl and malate forms?
| Label line | Printed | What it is | Note |
|---|---|---|---|
| L-Citrulline HCl | 100 mg | Citrulline as a hydrochloride salt | Dissolves easily; a small part of the weight is HCl |
| L-Citrulline Malate | 100 mg | Citrulline joined to malic acid | Common in workout powders; part of the weight is malate |
Both forms deliver citrulline. HCl, short for hydrochloride, is a salt form that mixes well. Malate is citrulline joined to malic acid, the sour acid in apples.
Part of each form's weight is the carrier. So the pure citrulline per capsule is a little under 200 mg. The label does not say how much under. Our Supplement Facts page explains salt forms in more detail.
What doses of citrulline have been studied?
- 200 mgPrinted in one Memodyne capsule
- 1,000 mg+Gram doses used in blood pressure trials
- Under 20%Most this could be of a 1 g dose
Trials of citrulline used gram doses, meaning 1,000 mg or more a day (Khalaf et al., 2019). One capsule's 200 mg is at most a fifth of even the smallest gram dose. Most trials used more than that.
A low dose is not proof of no effect. It does mean no study we found tested what 200 mg a day does.
Can L-citrulline lower blood pressure?
In some trials, yes, by a modest amount. A review of arginine and citrulline trials found small drops at gram doses (Khalaf et al., 2019). It also found the results vary and long-term data are limited.
Blood pressure matters for the brain over the years. But a supplement is not a replacement for checking your numbers and following your doctor's plan. If your blood pressure is high, the brain health basics guide explains why controlling it helps.
How do citrulline and arginine compare?
| Point | L-citrulline | L-arginine |
|---|---|---|
| Printed in Memodyne | 200 mg (two forms) | 400 mg (two forms) |
| What the body does with it | Turns it into arginine, mostly in the kidneys | Uses it to make nitric oxide |
| Loss before it reaches the blood | Less: it passes the gut and liver more easily | More: the gut and liver use some first |
| Main research | Blood pressure and exercise at gram doses | Blood pressure, exercise, one small memory trial |
| Heart attack data | No trial in our sources | VINTAGE MI: no benefit, more deaths |
| Drug cautions | Blood pressure drugs, nitrates, ED pills | Blood pressure drugs, nitrates, ED pills |
The two work as a team. Arginine is the direct raw material for nitric oxide. Citrulline refills arginine over a longer time. Their safety cautions are almost the same, because citrulline ends up as arginine.
Which medicines can interact with L-citrulline?
Ask before mixing with heart or blood pressure drugs
Citrulline might lower blood pressure. It may add to the effect of blood pressure drugs and nitrates such as nitroglycerin (WebMD, L-citrulline). Because it becomes arginine, the arginine cautions for ED pills like sildenafil apply too (Mayo Clinic, L-arginine).
Talk to your doctor first if you have
- Any blood pressure medicine, including water pills
- Nitroglycerin or another nitrate for chest pain
- ED pills, for example sildenafil, tadalafil or vardenafil
- A past heart attack: an arginine trial after heart attacks found more deaths in the arginine group
- Kidney disease, since the kidneys do the converting
The VINTAGE MI trial tested arginine, not citrulline (Schulman et al., JAMA 2006). Still, citrulline raises arginine, so ask your cardiologist first. Our side effects page lists what to watch for.
Could you be doubling up on citrulline?
Yes, if you use other products for blood flow or workouts. Many pre-workout powders and nitric oxide capsules contain citrulline, arginine or both. Adding Memodyne on top raises the total.
Read the labels of everything you take and add up the citrulline and arginine lines. Bring the totals to your pharmacist, especially if you also take blood pressure medicine. The label caution still applies: do not take more than one capsule a day.
Our post on nitric oxide supplements and blood pressure pills explains how these products can add up.
Honest note: does L-citrulline help memory?
No study we found shows that citrulline helps memory. Its research is about blood flow and muscles. The label calls Memodyne a “Cognitive Support Formula,” but no study of the product has been published.
Supplements are not proven to prevent dementia (NCCIH, Supplements for cognitive function). If memory loss is getting in the way of daily life, see a doctor. Some causes, like low B12 or a medicine side effect, can be treated (NIA, Memory problems and aging).
What should the first two weeks look like?
- Before day 1
Show the label to your doctor or pharmacist if you take any heart or blood pressure medicine.
- Days 1 to 3
Take one capsule with 8 oz of water, 20 to 30 minutes before breakfast.
- Days 4 to 7
Note any dizziness, headache or stomach upset. If you check blood pressure at home, keep doing it.
- Days 8 to 14
Keep the same time each day. Stop and call your doctor if you feel faint or light-headed.
The how to use page has more on building the habit.
L-citrulline FAQ: questions people ask
What is L-citrulline good for?
It is sold mainly for blood flow and exercise. The body turns it into arginine, the raw material for nitric oxide, and some gram-dose trials found modest blood pressure drops.
Is L-citrulline better than L-arginine?
It raises blood arginine more efficiently. In one study, oral citrulline raised arginine levels more than the same amount of arginine taken by mouth.
Does L-citrulline lower blood pressure?
Some trials at gram doses found modest drops, but results vary and long-term data are limited. Whether 200 mg does anything to blood pressure is unknown.
How much L-citrulline is in Memodyne?
One capsule lists 200 mg in two forms: 100 mg of L-citrulline HCl and 100 mg of L-citrulline malate. Part of that weight is the HCl or malate.
What is the difference between L-citrulline and citrulline malate?
Citrulline malate is citrulline joined to malic acid, so part of its weight is malate. Plain or HCl forms carry more citrulline per milligram.
Does L-citrulline help memory or focus?
No study we found shows that it does. Its research is about blood flow and exercise, not memory.
Can I take L-citrulline with blood pressure medicine?
Ask your doctor first. Citrulline might lower blood pressure and add to the effect of blood pressure drugs and nitrates.
What are the side effects of L-citrulline?
WebMD rates it possibly safe for short-term use. The main concern is low blood pressure when it is combined with drugs that also lower it.
Can you take L-citrulline and L-arginine together?
Many products combine them, and Memodyne does too. Both may lower blood pressure, so people on heart or blood pressure drugs should ask a doctor before taking the pair.
Which foods contain citrulline?
Watermelon is the best-known source, and the amino acid is named after it. Cucumbers, melons and squash also contain some.
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.
