Ingredient research hub
L-Citrulline
What it is
L-citrulline is an amino acid that the body can convert to arginine. It is found in watermelon and sold in supplements. It is not one of the nine essential amino acids; citrulline malate is a different preparation from isolated L-citrulline.
Why people look for it
Interest often concerns nitric oxide, exercise, and comparison with beetroot nitrate.
What research generally looks at
Research examines amino acid availability, vascular measurements, and exercise outcomes. More precursor availability is not proof of better endurance.
Important context
A small undisclosed amount in a blend cannot be equated with a trial of isolated citrulline. The beetroot comparison separates preparation, pathway, and outcome instead of declaring a universal winner.
Related research
Choose a specific evidence question below. Formula reviews provide label context; they do not establish that the complete product reproduces an ingredient study.
Energy
How to Increase Nitric Oxide Naturally: Foods, Exercise, and Evidence-Based StrategiesFood and exercise come first when supporting the body's nitric oxide pathways, and oral bacteria also play an important role. Beetroot and L-citrulline may be useful in specific contexts, but claims about boosting nitric oxide deserve cautious interpretation.
Planet Wellness Report · Sep 22, 2026
Energy
What Is Nitric Oxide? How It Supports Circulation, Energy, and ExerciseNitric oxide helps regulate blood vessel tone and circulation, but it is not a stimulant or a direct source of energy. Learn how the body produces it, what exercise research shows, and where beetroot and L-citrulline fit.
Planet Wellness Report · Sep 20, 2026
Nutrition
Beetroot vs. L-Citrulline for Nitric Oxide Support: Which Fits Your Goal?Compare beetroot and L-citrulline by nitric oxide pathways, vascular measures, exercise outcomes, and practical use—without assuming one is best for everyone.
Planet Wellness Report · Oct 7, 2026
Energy
CircO2 Review: What the 420 mg Blend Reveals—and HidesCircO2’s lozenge discloses vitamin C 100 mg, B12 1,000 mcg and a 420 mg total blend. It does not disclose individual beetroot, hawthorn, citrulline or sodium-nitrite amounts, nitrate content, or a separate elemental-magnesium dose. That prevents the dose comparisons central to its nitric-oxide positioning.
Planet Wellness Report · Sep 26, 2026
Related ingredients
Follow the ingredient definitions to compare roles and preparations, rather than treating them as interchangeable products.
Sources / Learn more
Products containing it
CircO2Advanced Bionutritionals
Lozenge with vitamin C, B12 and a 420 mg proprietary blend of beetroot, hawthorn, L-citrulline and sodium nitrite. Individual blend amounts and a separate elemental-magnesium amount are not declared.
Product inclusion indicates a catalog relationship, not an efficacy endorsement.