Independent supplement ratingsUS and Canada · Updated weekly
A ratings desk for a category that has spent thirty years grading its own homework.
A ratings desk for a category that has spent thirty years grading its own homework.
Veg capsules · 120 servings
250mg citrulline / 3,000–6,000mg studied
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A real, transparent product — just underdosed on the part that matters. NOW pairs L-arginine with L-citrulline at disclosed doses, which already puts it ahead of every proprietary-blend pill here. The catch is the citrulline amount: at around 250 mg it's a fraction of the 3,000 mg-plus used in the research, so you'd swallow a lot of capsules to reach a studied dose. Clean label, honest brand, dose just too small to do much.
Doses printed, no blend — good. But the citrulline is roughly 250 mg per serving against a studied range in the thousands, and L-arginine is poorly absorbed on its own, which is exactly why citrulline is the better-evidenced choice. You're getting the right ingredients at the wrong amounts.
Fine as a cheap, honest amino-acid supplement, but if citrulline is what you're after, a dedicated citrulline powder gets you a real dose far more cheaply than a handful of these.
Reviewed and fact-checked by the NFS editorial team · Last updated 08 Aug 2026