Nitrosigine (inositol-stabilized arginine silicate)

Also called inositol-stabilized arginine silicate, ASI, arginine silicate inositol complex, bonded arginine silicate.

Best grade D across 5 graded outcomes Amino acid Last checked

The short answer

From 8 sources

Nitrosigine (inositol-stabilized arginine silicate, ASI) is a branded arginine complex. At 1.5 g it raised blood arginine within 30 minutes and widened arteries on ultrasound about as much as 8 g citrulline malate. Small trials, most funded by or co-authored with the ingredient's maker, report faster complex-task scores after single or short-term doses (grade D); no trial has tested strength or endurance outcomes.

Every graded outcome on this page

5 rows · line = participants
  1. Grade DMood, energy and task accuracy in gamers over 7 days (with added inositol)Cognitionn 60
  2. Grade DReaction time and working memory in gamers (with added inositol)Cognitionn 26
  3. Grade DArtery widening (flow-mediated dilation) 60 minutes after a doseBlood flown 24
  4. Grade DMemory and overall cognition 60 minutes after one doseCognitionn 19
  5. Grade DComplex-task speed (Trail Making Test B) after 3 daysCognitionn 16
  6. 2 more graded outcomes, in the evidence chapter

Key facts

What it is
A complex of L-arginine, silicate and inositol (trademark Nitrosigine, Nutrition 21)21
Usual studied dose
1,500 mg (three 500 mg capsules) per day126
Absorption
Plasma arginine rose within 30 minutes and peaked at about 1.1 hours; serum silicon peaked at about 2.4 hours1
Blood-vessel response
1.5 g raised flow-mediated dilation 31% at 60 minutes, similar to 8 g citrulline malate (34%), versus −2% with placebo6
Funding
The 2016 cognition studies were funded by the ingredient maker, Nutrition 21, and the gamer trials tested its nooLVL product24

What it is

Nitrosigine is a trademarked complex of arginine, silicate and inositol and a popular sports-supplement ingredient.

How it works

Proposed

Arginine is the substrate the body uses to make nitric oxide, which relaxes blood vessels. The silicate-inositol complex is said to improve arginine delivery; one small study found higher plasma arginine and salivary nitrite after dosing. Links from these changes to better thinking or exercise are proposed, not shown.16

Forms, side by side

2 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.

Nitrosigine (inositol-stabilized arginine silicate) forms compared

2 forms
Nitrosigine (inositol-stabilized arginine silicate) forms compared: 2 forms by 3 attributes. Empty cells are labelled No data yet, or Not graded in the evidence row.
2 formsInositol-stabilized arginine silicate (Nitrosigine)Inositol-enhanced arginine silicate (nooLVL)
Absorption in peoplePlasma arginine rose within 30 minutes (peak about 1.1 hours) and silicon peaked at about 2.4 hours; after 14 days, baseline salivary nitrite was higher in 6 of 10 men.1No head-to-head human data.4
GI toleranceFound safe within a 14-day protocol in 10 men; the trial abstracts report no notable adverse events.15Adverse events were minimal and similar to placebo over 7 days.5
Studied forBlood flow and cognition (1.5 g)Cognition in video gamers (1.6 g)
  1. Inositol-stabilized arginine silicate (Nitrosigine)
    Absorption in people
    Plasma arginine rose within 30 minutes (peak about 1.1 hours) and silicon peaked at about 2.4 hours; after 14 days, baseline salivary nitrite was higher in 6 of 10 men.1
    GI tolerance
    Found safe within a 14-day protocol in 10 men; the trial abstracts report no notable adverse events.15
    Studied for
    Blood flow and cognition (1.5 g)
  2. Inositol-enhanced arginine silicate (nooLVL)
    Absorption in people
    No head-to-head human data.4
    GI tolerance
    Adverse events were minimal and similar to placebo over 7 days.5
    Studied for
    Cognition in video gamers (1.6 g)
Every cell holds data from a cited page; citation numbers link to the page that holds them.Scroll the table for every column

What the human research says

Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.

Trial map

5 graded outcomes, largest study first

All 5 graded outcomes found an improvement. The largest, a 2019 randomized trial of 60 people on mood, energy and task accuracy in gamers over 7 days (with added inositol), found an improvement.

1. Mood, energy and task accuracy in gamers over 7 days (with added inositol): improved, 60 people12. Reaction time and working memory in gamers (with added inositol): improved, 26 people23. Artery widening (flow-mediated dilation) 60 minutes after a dose: improved, 24 people34. Memory and overall cognition 60 minutes after one dose: improved, 19 people45. Complex-task speed (Trail Making Test B) after 3 days: improved, 16 people5

1Mood, energy and task accuracy in gamers over 7 days (with added inositol)

Improved · Grade D · RCT, 60 people, 2019

Healthy adults gaming at least 5 hours a week

Dose, result and source
Every graded outcome on this page, largest study first
OutcomeFoundPeopleStudyWho was studied
Mood, energy and task accuracy in gamers over 7 days (with added inositol)Improved60Grade D · RCT, 2019Healthy adults gaming at least 5 hours a week
Reaction time and working memory in gamers (with added inositol)Improved26Grade D · Crossover RCT, 2021Experienced video gamers, 18 men and 8 women
Artery widening (flow-mediated dilation) 60 minutes after a doseImproved24Grade D · Crossover RCT, 2020Healthy, normotensive, physically active young men and women
Memory and overall cognition 60 minutes after one doseImproved19Grade D · Crossover RCT, 2021Healthy young adults (mean age 21)
Complex-task speed (Trail Making Test B) after 3 daysImproved16Grade D · Crossover RCT, 2016Healthy, minimally active men aged 18–35
Each circle is one graded outcome on this page, numbered from the largest study down, and placed by how many people it studied (log scale). It shows who was studied and what was found, not advice about your dose.

Every graded row

5 rows

Showing 5 of 5 outcomes. Human trials only.

Grade DMood, energy and task accuracy in gamers over 7 days (with added inositol)CognitionImprovedRCT
n 60 · 2019

Improved Self-rated energy rose, anger fell and Trail Making B errors fell versus placebo; adverse events were minimal and similar between groups.

Design
RCT, n = 60, 2019
Population
Healthy adults gaming at least 5 hours a week
Form
Inositol-enhanced arginine silicate (nooLVL)
Dose
Daily dose (amount not stated in the abstract)
Duration
7 days
Source
Reference 5 · PubMed 31581523 (opens PubMed)
Grade DReaction time and working memory in gamers (with added inositol)CognitionImprovedCrossover RCT
n 26 · 2021

Improved Several Sternberg working-memory reaction times were faster than with placebo after gaming; other tests were better maintained.

Design
Crossover RCT, n = 26, 2021
Population
Experienced video gamers, 18 men and 8 women
Form
Inositol-enhanced arginine silicate (nooLVL)
Dose
1,600 mg single dose
Duration
Single dose before 1 hour of gaming
Source
Reference 4 · PubMed 34836014 (opens PubMed)
Grade DArtery widening (flow-mediated dilation) 60 minutes after a doseBlood flowImprovedCrossover RCT
n 24 · 2020

Improved FMD rose 31% after Nitrosigine and 34% after citrulline malate versus a 2% fall with placebo.

Design
Crossover RCT, n = 24, 2020
Population
Healthy, normotensive, physically active young men and women
Form
Nitrosigine
Dose
1.5 g single dose (vs 8 g citrulline malate or placebo)
Duration
Single dose per session
Source
Reference 6 · PubMed 32093766 (opens PubMed)
Grade DMemory and overall cognition 60 minutes after one doseCognitionImprovedCrossover RCT
n 19 · 2021

Improved Total RBANS and immediate-memory scores improved versus dextrose placebo; other cognitive domains did not differ.

Design
Crossover RCT, n = 19, 2021
Population
Healthy young adults (mean age 21)
Form
Inositol-stabilized arginine silicate with 12 g dextrose
Dose
1.5 g single dose
Duration
Single dose per session
Source
Reference 3 · PubMed 34959823 (opens PubMed)
Grade DComplex-task speed (Trail Making Test B) after 3 daysCognitionImprovedCrossover RCT
n 16 · 2016

Improved TMT B time fell 33% versus placebo about 10 minutes after the first dose and 35% from baseline after 3 days. A separate 14-day crossover in 11 trained men found a 28% drop from baseline.

Design
Crossover RCT, n = 16, 2016
Population
Healthy, minimally active men aged 18–35
Form
Inositol-stabilized arginine silicate
Dose
1,500 mg/day
Duration
3 days per period
Source
Reference 2 · PubMed 27869715 (opens PubMed)

What the numbers add up to

Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.

No exercise-performance trial

Despite pre-workout marketing, none of the cited trials measured strength, power or endurance; the closest outcome was artery widening at rest.62

How we got this: Outcomes in the evidence table

Mostly single doses

Three of the five evidence rows test one dose; the longest controlled exposure is 14 days in 11 men.6342

How we got this: Durations in the evidence table

Matched by citrulline

In the only head-to-head trial, 8 g of citrulline malate widened arteries about as much as 1.5 g of Nitrosigine.6

How we got this: 34% vs 31% FMD change

Studied doses

Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.

Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Doses studied in human trials

Doses studied in human trials ranged from 1,500 mg of Nitrosigine as a single dose or daily for up to 14 days, to 1,600 mg of an inositol-enhanced version before gaming or daily for 7 days.126345

Interactions and safety

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

What Nitrosigine meets

1 cited row

Medicines 1

Nitrosigine1 medicine · 0 supplements

Supplements and foods 0

No supplement rows in our sources.

  • Drug label or FDA notice
Rows as our evidence profiles cite them; links stay on this site. Line weight shows what backs a row, not how serious an interaction is. No line means none was found in our sources, not that a combination is safe. Not medical advice: ask your pharmacist.

Interactions

1 agent
Published interactions, grouped by kind
AgentWhat the source saysEvidence
Medicines1
Heart and blood-pressure medicines, erectile-dysfunction drugs and blood thinnerse.g. nitrates, sildenafil, warfarinHealth Canada's L-arginine monograph advises asking a health care practitioner before using more than 0.42 g of arginine a day with these medicines. Nitrosigine itself has no published interaction studies.8Drug label

Check with what you take

Kept on this device only

Add what you take. We list every interaction our evidence profiles cite between Nitrosigine and your picks, and between your picks.

Most cited:

Add a supplement or medicine you take to check it against Nitrosigine.

Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.

Not medical advice, and no dosing advice. An empty result means no row we cite names that pair, by name or through a drug class we can link the medicine to, not that a combination is safe. Where our sources name only a group of medicines we cannot match, the cabinet says so. Ask your pharmacist before you combine supplements and medicines.

Who should be careful

3 groups
People who have had a heart attack
Nitrosigine itself has not been studied here, but in the VINTAGE MI trial, plain L-arginine added to standard care did not help and was linked to more deaths.7
Pregnancy and breastfeeding
Health Canada's L-arginine monograph advises asking a health care practitioner before use; the Nitrosigine trials enrolled healthy non-pregnant adults only.81
Children and teenagers
Every cited trial enrolled adults.25
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.

Reading the label, and the cost per dose

Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.

How to read the label

2 checks
Label dose vs studied dose

The trials used 1,500 mg of Nitrosigine; pre-workout blends may list less, and the label amount is the complex, not pure arginine.162

Nitrosigine vs nooLVL

The gamer trials tested nooLVL, which adds extra inositol, so their results are not a direct test of Nitrosigine alone.45

Have the bottle? Photograph its Supplement Facts panel and see each line, nitrosigine (inositol-stabilized arginine silicate) included, beside the doses and forms the trials used in Label X-Ray.

Cost per studied dose, without the sales pitch

Your numbers, no product data

Enter the price, servings and the amount per serving from your label.

Formula: price ÷ (servings × amount per serving) × reference amount. Use the amount printed on the Supplement Facts panel, not the front-of-pack compound weight. Reference amounts are what trials studied or official limits, not advice for you. We don't rank or link products in this calculator.

Frequently asked questions

Short answers to common questions; the numbers link to the sources below.

Common questions

6 answers
Does Nitrosigine boost nitric oxide?

It raised blood arginine within 30 minutes, and baseline salivary nitrite rose after 14 days in a 10-man study. A 1.5 g dose widened arteries on ultrasound an hour later.16

Does Nitrosigine improve workouts?

No published trial cited here measured strength, power or endurance. The evidence covers blood-vessel response and short cognitive tests.62

Does Nitrosigine help focus?

Small trials found faster complex-task or better memory scores after single, 3-day or 7-day doses. Three of them were funded by the maker and a fourth had a co-author from the supplier.2345

Is Nitrosigine safe?

It was found safe within a 14-day protocol in 10 men and short trials reported minimal side effects. Long-term safety has not been studied.15

Is Nitrosigine better than citrulline?

In the only head-to-head study, 1.5 g Nitrosigine and 8 g citrulline malate raised artery widening by similar amounts (31% vs 34%).6

What is Nitrosigine?

A trademarked complex of arginine, silicate and inositol (inositol-stabilized arginine silicate), described by researchers as a popular sports supplement.26

Sources

8 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.

Sources cited on this page

8 sources
  1. 1A clinical evaluation to determine the safety, pharmacokinetics, and pharmacodynamics of an inositol-stabilized arginine silicate dietary supplement in healthy adult males.PK study Clin Pharmacol, 2015 · PMID 26504409
  2. 2Randomized Prospective Double-Blind Studies to Evaluate the Cognitive Effects of Inositol-Stabilized Arginine Silicate in Healthy Physically Active Adults.Crossover RCT Nutrients, 2016 · PMID 27869715
  3. 3Acute Inositol-Stabilized Arginine Silicate Improves Cognitive Outcomes in Healthy Adults.Crossover RCT Nutrients, 2021 · PMID 34959823
  4. 4Effects of Inositol-Enhanced Bonded Arginine Silicate Ingestion on Cognitive and Executive Function in Gamers.Crossover RCT Nutrients, 2021 · PMID 34836014
  5. 5A Prospective Study Evaluating the Effects of a Nutritional Supplement Intervention on Cognition, Mood States, and Mental Performance in Video Gamers.RCT Nutrients, 2019 · PMID 31581523
  6. 6Acute effects of Nitrosigine® and citrulline malate on vasodilation in young adults.Crossover RCT J Int Soc Sports Nutr, 2020 · PMID 32093766
  7. 7L-arginine therapy in acute myocardial infarction: the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) randomized clinical trial.RCT JAMA, 2006 · PMID 16391217
  8. 8L-Arginine: natural health product monograph (risk information; dated July 25, 2025)Guideline Health Canada, Natural and Non-prescription Health Products Directorate, 2025 · webprod.hc-sc.gc.ca

What changed

Every dated change to this page: what changed, who made it and why.

Change log

3 entries
Dated changes to this page
DateChangeWho and why
allFirst draft. Every PMID checked against NCBI E-utilities esummary (title, journal and year taken from the record) and abstracts read for each cited row.Writer: Kymata Health EditorialTrigger: new page
allAdversarial review pass: every number in each evidence row's result, dose, duration, n and population fields was machine-checked against its PubMed abstract, and figures not in an abstract were confirmed in the PMC full text (noted per row). Unverified study-country, funding and mechanism wording was removed or sourced, rows whose sample size could not be confirmed were dropped, and retraction, erratum and expression-of-concern flags were checked on every PMID (two errata, noted on their rows; no retractions). Page set indexable.Writer: Kymata Health EditorialTrigger: review
safetyIndependent review: disclosed maker funding on every cognitive trial from the full texts (Nutrition 21 funded three; a supplier co-author on a fourth), corrected the summary and focus FAQ that said only one or some were sponsor-funded, and added the Health Canada L-arginine medicine-interaction caution.Writer: Kymata Health EditorialTrigger: review

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