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L‑Citrulline & L‑Arginine for nitric oxide support.*Both building blocks. Zero stimulants.
400 mg L‑citrulline malate and 400 mg arginine in two forms (HCl + AKG) in two vegan capsules a day. Your body turns citrulline into arginine, and uses arginine to make nitric oxide: the signal that relaxes your blood vessels, supporting healthy blood flow and circulation.* No caffeine, no beta-alanine.
- Supports nitric oxide production and healthy circulation*
- 400 mg L‑citrulline malate + 400 mg L‑arginine (HCl + AKG) per serving
- No caffeine, no beta-alanine: take it on training and rest days
- Every amount printed. 90 days to decide, or every dollar back
*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
Is it a pre-workout?
No. There is no caffeine and no beta-alanine, so there is nothing to time around a workout. Take two capsules a day with a full glass of water, on training days and rest days.
Why citrulline and arginine together?
Your body turns citrulline into arginine, and makes nitric oxide from arginine. In a study of healthy men, 1 g of each taken together raised blood arginine more than 2 g of either one alone.
What if it's not for me?
Take it for up to 90 days. If it isn’t for you, tell us within 90 days of delivery and get every dollar back.
Your muscles run on blood flow. Nitric oxide keeps it moving.
You train, you eat right, and you don’t want another scoop of caffeine just to feel your session. What you’re after is simpler: blood, oxygen and nutrients reaching the muscles doing the work, on training days and every day in between.
Nitric oxide is the signal that tells your blood vessels to relax and widen, so more blood can flow through. Your body makes it from the amino acid arginine.
The catch: much of the arginine you swallow is broken down before it reaches your blood. Citrulline is absorbed and turned into arginine inside your body. That’s why this stack gives you both, citrulline malate and arginine in two forms, to support nitric oxide production every day.*
Nobel Prize in Medicine for the discovery that nitric oxide is the signal that relaxes blood vessels.
Taken together, 1 g citrulline and 1 g arginine raised blood arginine more than 2 g of either alone, in healthy men.
stimulants. Three actives, a vegetable capsule and brown rice flour. That’s the whole label.
Supplement Facts panel
How two capsules a day work
Where you want blood flow to show up.
Nitric oxide helps your blood vessels relax, supporting healthy blood flow and circulation.* Here’s where you want that.
Training that feels fed, not forced
Blood carries oxygen and nutrients around your body. Citrulline and arginine support the nitric oxide that helps keep it flowing.*
Studies that measured performance used more per day than one serving. See the research below.
Circulation support, gym or no gym
Long desk days, long shifts, long drives: your body makes nitric oxide every day, not only when you train. Two capsules support healthy circulation, wherever your day takes you.*
Two capsules a day with a full glass of water. Don’t take more than the label says.
Calm, even on training days.
No caffeine means no jittery edge and no late-day crash from your supplement, and no beta-alanine tingle. Just the two amino acids your body uses to make nitric oxide.
Everyone is different. Take it with a full glass of water.
What customers say.
Not another pre-workout
I already drink enough coffee. I wanted blood flow support without adding more caffeine, and this is two capsules with breakfast.
Both in one bottle
I was buying citrulline and arginine separately. Having both in one bottle is easier, and the label is short enough to actually read.
Sessions feel smoother
Hard to put into words, but my sessions feel smoother and I don’t get the crash I had with stim pre-workouts.
Results vary.
Know what I’m taking
I wanted to know exactly what I’m taking. Three ingredients, every amount on the label.
No shaker needed
No sour powder, no shaker bottle. I take the capsules with a glass of water and I’m done.
Fits my long shifts
I’m on my feet all day for work. I wanted simple daily support for circulation with no jitters, and this is it.
Results vary.
$0.93 a day with Subscribe & save, for both building blocks.
L‑Citrulline & L‑Arginine Stack
400 mg L‑citrulline malate, 350 mg L‑arginine HCl and 50 mg L‑arginine AKG in two vegan capsules. 60 capsules, 30 servings. Made in the USA with globally sourced ingredients.
- Both building blocks, one bottleCitrulline malate plus arginine in two forms in every serving, so there is nothing to buy twice. In a study, the pair raised blood arginine more together than either alone (1 g of each, at least 2.5 times our serving).
- Capsules, not a powderNo scoop, no scale, no shaker, no sour taste. Two capsules with a glass of water, at home or on the road.
- Right at the category medianNitric oxide supplements on Google Shopping have a median one-time price of $33.99 (October 2026). Ours is $34.99 one-time, or $27.99 a bottle with Subscribe & save.
- Made for every dayIn the studies that ran a week or longer, citrulline was taken every day. A bottle every 4 weeks means your daily serving never runs out. Skip or cancel anytime.
- 90 days to decide, free shippingEvery dollar back if it’s not for you, within 90 days of delivery. Free shipping on every order, no minimum.
Combination study: Suzuki et al., 2017. Median one-time price: Google Shopping, "nitric oxide supplement", October 2026. Amounts: Supplement Facts panel.
Your next 90 days, two capsules at a time.
Your body makes nitric oxide every day, and the longer studies gave citrulline daily. So make it part of your day.
Questions, answered.
Is 400 mg enough?
It’s less than the studies used, and we’d rather say so. Each serving has 400 mg L‑citrulline malate and 400 mg arginine in two forms. The studies on this page used 1 g to 1.2 g each of citrulline and arginine, 3 to 6 g of citrulline a day, or 6 to 8 g of citrulline malate before training. Two capsules a day is the most the label allows. What you get every day: both building blocks, no stimulants, every amount printed.
Is this a pre-workout? Will I feel a rush?
No. There’s no caffeine and no beta-alanine, so no buzz and no tingle. It’s daily nitric oxide support you can take on training days and rest days.
Why citrulline and arginine together?
Your body makes nitric oxide from arginine. Much of the arginine you swallow is broken down before it reaches your blood; citrulline is absorbed and turned into arginine in your body (Schwedhelm et al., 2008). In healthy men, 1 g of each taken together raised blood arginine more than 2 g of either alone (Suzuki et al., 2017).
Is citrulline malate the same as citrulline?
Citrulline malate is citrulline bound to malic acid. It’s the form most strength studies used. Because part of the 400 mg is malate, the citrulline itself is less than 400 mg.
Are there side effects?
L‑arginine taken by mouth is generally considered safe (Mayo Clinic). Higher amounts can cause nausea, stomach pain, bloating, diarrhea or headache. Take your capsules with a full glass of water, and stop if something doesn’t agree with you.
Who shouldn’t take it?
It’s for adults 18 and over. Talk to your doctor first if you’re pregnant or breastfeeding or have a medical condition. If you take prescription medication, especially for your heart or blood pressure, talk to your doctor first. L‑arginine isn’t recommended if you have had a recent heart attack (Mayo Clinic).
Can I take it with creatine or my pre-workout?
There’s no caffeine, creatine or beta-alanine in it, so nothing doubles up. If your pre-workout already contains citrulline or arginine, check the total on both labels.
When should I take it?
Any time of day, every day, with a full glass of water (6 to 8 oz). With breakfast is easy to remember.
How does subscribe & save work?
You pay $27.99 a bottle instead of $34.99 (20% off), and a new bottle ships every 4 weeks with free shipping. Skip a delivery or cancel anytime.
What if it’s not for me?
Take it for up to 90 days. If it isn’t for you, tell us within 90 days of delivery and get every dollar back.
The science, with the fine print.
Each row shows the dose and who was studied. Most studies used more than one serving of ours, and we’d rather show you that than hide it. None of them tested this product.
Dose and conditions: 20 healthy volunteers; six dosing regimens of citrulline and arginine for 1 week, up to 3 g citrulline twice a day.
Worth knowing: After 1 week, no dose improved blood vessel widening (FMD) over baseline. Up to 15 times our serving.
Dose and conditions: Healthy men; 1 g of each together versus 2 g of either alone.
Worth knowing: At least 2.5 times our serving. The authors work for an amino acid maker.
Dose and conditions: 24 male college soccer players; 1.2 g citrulline plus 1.2 g arginine a day for 7 days.
Worth knowing: About 3 times our serving. Funded by an amino acid maker. A review of single doses of citrulline found no effect on endurance (Harnden et al., 2023).
Dose and conditions: Review of randomized trials in adults; 3 to 6 g citrulline a day.
Worth knowing: No effect was seen after a single dose. 8 to 15 times our serving, or more.
Dose and conditions: 8 studies, 137 strength-trained participants; 6 to 8 g citrulline malate 40 to 60 minutes before training.
Worth knowing: Up to 20 times our serving. In another trial, 8 g citrulline malate plus 3 g arginine didn’t change measured blood flow to the arm muscle or muscle pump (Bürkle et al., 2022).
Links open the study abstract. Checked October 2026.
Start todayNitric oxide support, minus the stimulants. Here’s what’s different.
Our stackA note from Vitasy.
"We won’t pretend this is the dose from the studies, because it isn’t. Two capsules give you 400 mg citrulline malate and 400 mg arginine in two forms, the building blocks your body uses to make nitric oxide. Made in the USA with globally sourced ingredients, no stimulants, every amount printed. The studies used more, and we show you exactly how much. Take it for 90 days. If it isn’t for you, every dollar back."
The Vitasy team
90 days to make it part of your training.
Take two capsules a day for up to 90 days. If it isn’t for you, tell us within 90 days of delivery and get every dollar back. Free shipping, no minimum.
Nitric oxide support, the stimulant-free way. Start your two‑capsule routine today.
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