L-Citrulline

L-Citrulline is an Amino Acid supplement available in 1 form.

FormulaForge carries a single form of L-Citrulline, so there is no form to choose here. Forms on the market do differ in how well they absorb, which is why it is worth checking the form named on any product label.

L-Citrulline Preferred (Preferred Form) has a bioavailability rating of good absorption.

L-Citrulline is converted to L-arginine in the kidneys, bypassing first-pass liver metabolism that limits oral arginine effectiveness. Research demonstrates L-citrulline raises plasma arginine levels more effectively than equivalent doses of L-arginine itself. Clinical studies support its use for exercise performance, blood flow, and blood pressure management.

In a randomized crossover study, L-citrulline raised plasma arginine to a similar magnitude as direct arginine supplementation while additionally increasing plasma citrulline, demonstrating citrulline as an effective arginine precursor. PMID: 26023227

Research suggests L-citrulline may help support exercise performance and post-exercise recovery perception in active adults. In a double-blind crossover trial of 22 trained men, oral L-citrulline reduced 4-km cycling completion time by 1.5% versus placebo. PMID: 26900386

Research suggests L-citrulline may help support blood flow to working muscle during exercise. In a double-blind crossover trial of 25 older adults, femoral blood flow during exercise increased in older men — but not in older women. PMID: 28940638

L-Citrulline is classified as Preferred Form by FormulaForge — our top recommendation for L-Citrulline. It carries a bioavailability rating of good absorption, meaning more of the active compound reaches your tissues per dose unit compared to lower-rated forms.

When choosing a L-Citrulline supplement, read the label for the specific form name — that is what determines how much you actually absorb. Preferred Forms have the strongest research-backed evidence for efficient absorption.

Other forms may be appropriate depending on individual goals, cost considerations, and your healthcare provider’s guidance. The best form for you depends on your specific health needs.

Individual dose requirements vary based on health goals, body weight, and existing nutrient intake. Your healthcare provider can help you determine an appropriate amount of L-Citrulline for you.

Side Effects: Consult your healthcare provider regarding tolerability, particularly at higher doses.

These statements are based on structure/function research and have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare provider before starting or changing a supplement regimen.

The following studies and findings inform FormulaForge classifications for L-Citrulline:

In a randomized crossover study, L-citrulline raised plasma arginine to a similar magnitude as direct arginine supplementation while additionally increasing plasma citrulline, demonstrating citrulline as an effective arginine precursor. PMID: 26023227

Research suggests L-citrulline may help support exercise performance and post-exercise recovery perception in active adults. In a double-blind crossover trial of 22 trained men, oral L-citrulline reduced 4-km cycling completion time by 1.5% versus placebo. PMID: 26900386

Research suggests L-citrulline may help support blood flow to working muscle during exercise. In a double-blind crossover trial of 25 older adults, femoral blood flow during exercise increased in older men — but not in older women. PMID: 28940638