We evaluated NO booster supplements for citrulline dose, ingredient transparency, supporting ingredients, third-party testing, and value. The science is clear: L-citrulline is the most effective oral NO precursor, and dose matters — underdosed products are a waste of money.
Best Nitric Oxide Supplements (2026)
This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer
Our Verdict
The best nitric oxide supplement provides 6-8g L-citrulline or 8g citrulline malate per serving, optionally combined with beetroot extract, with no proprietary blends and third-party testing.
Best By Category
TL;DR — Quick Answer
The best nitric oxide supplement provides at least 6g L-citrulline or 8g citrulline malate per serving. L-citrulline raises blood arginine and NO levels more effectively than L-arginine itself. Look for transparent labeling, no proprietary blends, and optional beetroot for multi-pathway NO support.
Our recommendations are based on published research, not commission rates. Some links below are affiliate links — we may earn a commission at no extra cost to you. How we evaluate products
4+ products evaluated · Ratings based on published research, not commissions
Quick Comparison
#1Transparent Labs Bulk Pre-Workout
9.2/10
Transparent Labs
Best for: Overall pre-workout with clinical citrulline dose
Citrulline Malate (8g) · 8g citrulline malate (2:1)
Powder · Third-Party Tested
$1.50
#2Jacked Factory N.O. XT Nitric Oxide Booster
8.9/10
Jacked Factory
Best for: Pure NO focus without caffeine
L-Citrulline (7g) + Nitrosigine · 7g L-citrulline + 1.5g Nitrosigine
Powder · Third-Party Tested
$1.17
#3HumanN SuperBeets Heart Chews
8.2/10
HumanN
Best for: Nitrate pathway NO / Blood pressure / Non-powder option
Beetroot Extract (concentrated dietary nitrate) · 500mg beetroot concentrate per serving
Chew · Third-Party Tested
$0.83
#4Nutricost L-Citrulline
8.4/10
Nutricost
Best for: Budget / Pure citrulline
L-Citrulline · 3g per scoop (use 2 scoops for 6g clinical dose)
Unflavored Powder · Third-Party Tested
$0.20
| # | Product | Best For | Ingredient & Dose | Form & Testing | Price | Rating | |
|---|---|---|---|---|---|---|---|
| 1 | Transparent Labs Bulk Pre-Workout Transparent Labs | Overall pre-workout with clinical citrulline dose | Citrulline Malate (8g) 8g citrulline malate (2:1) | Powder Third-Party Tested | $1.50 | 9.2/10 | |
| 2 | Jacked Factory N.O. XT Nitric Oxide Booster Jacked Factory | Pure NO focus without caffeine | L-Citrulline (7g) + Nitrosigine 7g L-citrulline + 1.5g Nitrosigine | Powder Third-Party Tested | $1.17 | 8.9/10 | |
| 3 | HumanN SuperBeets Heart Chews HumanN | Nitrate pathway NO / Blood pressure / Non-powder option | Beetroot Extract (concentrated dietary nitrate) 500mg beetroot concentrate per serving | Chew Third-Party Tested | $0.83 | 8.2/10 | |
| 4 | Nutricost L-Citrulline Nutricost | Budget / Pure citrulline | L-Citrulline 3g per scoop (use 2 scoops for 6g clinical dose) | Unflavored Powder Third-Party Tested | $0.20 | 8.4/10 |
Detailed Reviews
Top Pick
1
Transparent Labs Bulk Pre-Workout
Transparent Labs
9.2/10
$1.50/serving
Ingredient: Citrulline Malate (8g)
Dose: 8g citrulline malate (2:1)
Form: Powder
Testing: Third-Party Tested
8g citrulline malate (2:1)Clinical range: 6-8g L-citrulline
Clinical dose
Why we recommend it: Full 8g citrulline malate (2:1) — the exact dose and form used in clinical trials. Every ingredient dose is disclosed on the label — no proprietary blends. Also includes beta-alanine, betaine, and other evidence-based performance ingredients. One of the most transparently dosed pre-workouts available.
Ideal for: Overall pre-workout with clinical citrulline dose
Not ideal for: Evening workouts or individuals sensitive to 200mg caffeine
Pros
- Full 8g citrulline malate
- 100% transparent labeling
- Multiple evidence-based ingredients
- Third-party tested
Cons
- Higher price (includes other ingredients)
- Contains 200mg caffeine
- Not citrulline-only product
- Large scoop size
Gluten-freeNon-GMOVegan
2
Jacked Factory N.O. XT Nitric Oxide Booster
Jacked Factory
8.9/10
$1.17/serving
Ingredient: L-Citrulline (7g) + Nitrosigine
Dose: 7g L-citrulline + 1.5g Nitrosigine
Form: Powder
Testing: Third-Party Tested
7g L-citrulline + 1.5g NitrosigineClinical range: 6-8g L-citrulline
Clinical dose
Why we recommend it: Dedicated nitric oxide supplement (no caffeine or other stimulants) with a clinical 7g L-citrulline dose plus 1.5g Nitrosigine (inositol-stabilized arginine silicate) for enhanced NO production. Great for evening workouts or stimulant-sensitive individuals. Transparent labeling.
Ideal for: Pure NO focus without caffeine
Not ideal for: Those wanting an all-in-one pre-workout with energy and performance support
Pros
- 7g clinical citrulline dose
- Nitrosigine for enhanced NO
- No caffeine/stimulants
- Transparent labeling
Cons
- Slightly below 8g citrulline ideal
- Premium pricing
- Limited flavors
- Newer formulation
Gluten-freeNon-GMOVegan
3
HumanN SuperBeets Heart Chews
HumanN
8.2/10
$0.83/serving
Ingredient: Beetroot Extract (concentrated dietary nitrate)
Dose: 500mg beetroot concentrate per serving
Form: Chew
Testing: Third-Party Tested
500mg beetroot concentrate per servingClinical range: 300-500mg dietary nitrate
Partial dose
Why we recommend it: Concentrated beetroot in a convenient chew form — no powder mixing required. HumanN is a beetroot research company founded on the science of dietary nitrate. Uses the nitrate-nitrite-NO pathway, which is distinct from the citrulline/arginine pathway. Tastes like a gummy.
Ideal for: Nitrate pathway NO / Blood pressure / Non-powder option
Not ideal for: Athletes requiring full-dose citrulline for peak workout performance
Pros
- Convenient chew form
- Beetroot-research company
- Tastes good (gummy-like)
- No powder mixing
Cons
- No citrulline (nitrate pathway only)
- Contains added sugars
- Lower nitrate than juice/powder
- Less flexible dosing
Gluten-freeNon-GMO
4
Nutricost L-Citrulline
Nutricost
8.4/10
$0.20/serving
Ingredient: L-Citrulline
Dose: 3g per scoop (use 2 scoops for 6g clinical dose)
Form: Unflavored Powder
Testing: Third-Party Tested
3g per scoop (use 2 scoops for 6g clinical dose)Clinical range: 6-8g L-citrulline
Clinical dose
Why we recommend it: Pure L-citrulline at an unbeatable price — $0.20 per 6g clinical dose. No flavors, sweeteners, or additives. Mix into any beverage or stack with your own pre-workout ingredients. Third-party tested. The most cost-effective way to get a clinical citrulline dose.
Ideal for: Budget / Pure citrulline
Not ideal for: Those wanting a flavored all-in-one pre-workout
Pros
- Cheapest clinical citrulline dose ($0.20)
- Pure — no additives
- Third-party tested
- Flexible stacking
Cons
- Unflavored (sour taste)
- Requires 2 scoops for full dose
- No supporting ingredients
- No beetroot or Nitrosigine
VeganGluten-freeNon-GMO
How to Choose
Citrulline Dose Is Everything
Do not buy an NO supplement with less than 6g L-citrulline or 8g citrulline malate per serving. Underdosed products are the #1 problem in this category. Many popular pre-workouts include only 3-4g citrulline, which is below the clinical threshold. If the product uses a proprietary blend, the citrulline dose is almost certainly subtherapeutic.
L-Citrulline vs L-Arginine
Despite arginine being the direct NO precursor, oral citrulline is more effective because arginine undergoes extensive first-pass metabolism in the liver (40-60% degraded by arginase). Citrulline bypasses this entirely and is converted to arginine in the kidneys. A 2008 pharmacokinetic study confirmed citrulline raises plasma arginine more effectively than arginine itself.
Consider Multi-Pathway NO Support
The body produces NO through two distinct pathways: the NOS enzyme pathway (citrulline/arginine) and the nitrate-nitrite-NO pathway (beetroot/dietary nitrate, mediated by oral bacteria). Combining citrulline with beetroot extract covers both pathways for potentially synergistic effects. Some products also include Nitrosigine (inositol-stabilized arginine silicate) for an additional NO-boosting mechanism.
How We Evaluate
Every product is scored against these weighted criteria. Our ratings reflect clinical evidence and product quality, not commission rates.
Citrulline Dose
35%Clinical studies showing NO and exercise benefits used 6-8g L-citrulline or 8g citrulline malate. Products below these thresholds are penalized.
Ingredient Transparency
25%No proprietary blends. You need to verify that citrulline is dosed at clinical levels, not hidden in a "pump blend."
Supporting Ingredients
15%Beetroot (dietary nitrate), agmatine, and nitrosigine provide additional NO support through complementary pathways.
Testing & Purity
15%Third-party testing for amino acid content verification. Informed Sport or NSF certification preferred.
Value
10%Cost per clinically effective serving. Bulk citrulline powder offers the best raw value.
Frequently Asked Questions
What is the best nitric oxide supplement?
What is the best nitric oxide supplement?
Transparent Labs Bulk provides the best overall NO support with a full 8g citrulline malate dose and transparent labeling. For pure NO without stimulants, Jacked Factory N.O. XT offers 7g citrulline + Nitrosigine. For budget pure citrulline, Nutricost at $0.20/serving cannot be beat. For beetroot-based NO, HumanN SuperBeets is the most convenient.
Does L-arginine work for nitric oxide?
Does L-arginine work for nitric oxide?
L-arginine is the direct precursor to NO, but oral supplementation is inefficient because 40-60% is degraded by arginase in the liver before reaching the bloodstream. L-citrulline bypasses liver metabolism entirely and actually raises plasma arginine levels higher than arginine itself. Most sports nutrition researchers now recommend citrulline over arginine for NO support.
References
- Schwedhelm E, Maas R, Freese R, et al. (2008). Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine. British Journal of Clinical Pharmacology. DOI PubMed
- Trexler ET, Persky AM, Ryan ED, et al. (2019). Acute Effects of Citrulline Supplementation on High-Intensity Strength and Power Performance. Sports Medicine. DOI PubMed
- Siervo M, Lara J, Ogbonmwan I, Mathers JC (2013). Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults. Journal of Nutrition. DOI PubMed