NutraBio · L-arginine · Powder

Is NutraBio L-Arginine underdosed?

1 serving = 1 scoop (1.5 g)Directions: 2–3 servings a dayLabel as of 21 May 2025 · NIH DSLD

Verdict

1.5 g per servingone dose · studies use 0.15 g/kg of l-arginine

Below research dose

One serving contains 1.5 g; studies use 0.15 g/kg (11.25 g at 75 kg) in one dose before training. The label's directions allow 2–3 servings a day. Studies dose it by bodyweight; this uses 75 kg.

One serving gives 1.5 g, so reaching the low end of what studies use (11.25 g) takes 7.5 servings at once; it ranks 5th of 17 L-arginine supplements here by dose.

To reach the research dose. It would take 8 servings at once (8 scoops), 12 g, to reach the 11.25 g at 75 kg studies use, more than the label's directions, which allow 2–3 servings a day.

What the label says

L-Arginine per serving
1.5 g in 1 scoop (1.5 g)
Servings a day
2–3 servings a day
L-Arginine a day, as directed
3–4.5 g
Research dose
0.15 g/kg Evidence: Weak
Suggested use: Take 1 serving with your favorite beverage 2-3 times daily as needed.
The label's directions, as printed.

More about l-arginine: forms, timing and the studies behind the dose.

Same category, compared

All 17 L-arginine supplements we checked, ranked by dose (commission never changes the order). Studies use 0.15 g/kg of l-arginine; servings counted to 11.25 g.

ProductPer servingServings to reach itForm
NOW Sports L-Arginine Powder6 g1.9 at oncePowders
Nutricost L-Arginine Powder5 g2.3 at oncePowders
Doctor's Best Pure L-Arginine Powder4.96 g2.3 at oncePowders
Micro Ingredients L-Arginine1.5 g7.5 at onceTablets
NutraBio L-Arginine (this product)1.5 g7.5 at oncePowders
Pure Encapsulations L-Arginine1.16 g9.7 at onceCapsules
Puritan's Pride L-Arginine 1000 mg1 g11.3 at onceCapsules
Thorne L-Arginine1 g11.3 at onceCapsules
Best Naturals L-Arginine 1000 mg827 mg13.6 at onceTablets
Havasu Nutrition L-Arginine Capsules + L-Citrulline827 mg13.6 at onceCapsules
Jarrow Formulas Arginine 1000 mg827 mg13.6 at onceTablets
Nature's Bounty L-Arginine 1000 mg827 mg13.6 at onceTablets
Source Naturals L-Arginine 1,000 mg827 mg13.6 at onceTablets
NOW L-Arginine 700 mg700 mg16.1 at onceCapsules
Nutricost L-Arginine + L-Citrulline 750 mg500 mg22.5 at onceCapsules
Nutricost L-Arginine 500 mg500 mg22.5 at onceCapsules
Swanson L-Arginine 500 mg500 mg22.5 at onceCapsules

Where the reference doses come from

  1. L-Arginine, 0.15 g/kg: Viribay et al., 2020.
  2. Label data: National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Label Database, 2026. https://dsld.od.nih.gov/. Label 329428, including its servings a day.

For a supplement taken as one dose we judge one serving, and show the most the label allows in a day. Read the full methodology or the corrections log.