L-Citrulline

L-citrulline reference formula at a default of 3,000 mg per serving, developed as a powder or capsule.

L-Citrulline is a reference formula for brands building a single-ingredient amino acid product around 3,000 mg per serving. The brand sets the final amount for its market, and reference labels span 500 to 6,750 mg per serving.

Powder is the lead format because a gram-level dose suits a scoop, and capsule is developed for brands that want a portable unit. The work centers on dose and taste: three grams of a bulky, slightly sour amino acid is a large unit in a capsule and a flavor challenge in a drink.

Ingredient Composition

IngredientPer ServingRaw Material FormAlternative Form (same amount of active)
L-Citrulline3000 mgL-citrulline free-form powder, specified on a declared-weight basis; 3,000 mg per servingCitrulline malate, a different compound with its own weight per gram of citrulline, with the input recalculated from the supplier’s ratio

The amount is stated as mg of L-citrulline. L-citrulline is C6H13N3O3, 175.19 g/mol (PubChem CID 9750); the free form has no salt or hydrate conversion. If citrulline malate is chosen, the specification states the citrulline-to-malate ratio and the input is calculated from it.

Intended Benefits & Formula Rationale

This formula is designed for products positioned around sports nutrition and amino acid supplementation. L-citrulline is included as the single ingredient so that the concept stays on one amino acid.

Intended Benefit DirectionKey IngredientsFormulation Rationale
Nitric oxide-related amino acid for exerciseL-CitrullineA systematic review states that citrulline supplementation has been reported to affect aerobic exercise performance and related outcomes, probably through its relationship to endogenous nitric oxide production [1]. Evidence: Referenced
Aerobic performanceL-CitrullineThe same review pooled 10 studies and found no positive effect of citrulline supplementation on aerobic performance, rate of perceived exertion, oxygen uptake kinetics or lactate, and describes the research as controversial [1]. Evidence: Contested

The amount is a design choice. The review in [1] covers aerobic outcomes in general and does not test this formula, and its pooled findings are not positive, so the positioning is decided by the brand together with the claim review for each market.

Available Formats

Reference labels are mostly powders, with capsules and a few tablets behind them; powder and capsule are developed here.

FormatUnitPer ServingPack SizeOther Ingredients (typical)Suitability
Powder1 scoop, 3 gL-citrulline 3,000 mg90 g or 300 g tubNone, or flavor, sweetener, acidLead format; unflavored or flavored
Capsule4 capsulesL-citrulline 3,000 mg240 capsules (60 servings)Vegetable capsule shell, flow agentPortable unit; several capsules per serving

Raw Material Input & Fill (Design Estimate)

Design estimates. L-citrulline is assumed at 100% of its declared weight, so 3,000 mg per serving needs 3,000 mg of raw material; the supplier’s assay is applied once the lot is chosen.

FormatRaw Material Input per UnitDesign FillBalance for ExcipientsVerification Before Scale-Up
Powder3,000 mg per scoop (unflavored)3 g per scoop; 5 g for the flavored version0 mg unflavored, 2,000 mg flavoredScoop volume against weight, dissolution, clumping, taste
Capsule750 mg per capsule780 mg per capsule30 mgPowder flow and bulk density, fill weight variation, disintegration

Tablet, liquid and gummy are separate projects, because a gram-level amino acid dose changes the compression and solubility work in those systems.

Formulation Considerations

Dose against unit size. At 750 mg per capsule the serving takes four capsules, and a size 00 capsule is close to its limit at that fill. Brands that want fewer capsules move to the powder format or a larger serving schedule.
Taste and acidity. L-citrulline is slightly sour and sweet, and an unflavored scoop is accepted by some buyers. A flavored version needs acid and sweetener tuning, which is tested in water and juice.
Dissolution. The powder dissolves well in water at room temperature at this dose. Particle size and wetting decide whether the scoop clumps on contact with water.
Form choice. Citrulline malate is a common alternative that carries a second component per gram of citrulline. A switch changes the input, the label amount and the taste.

Customization Options

Brands adjust the amount, the form, the format and the add-ons.

ParameterRangeNote
L-citrulline per serving750, 2000, 3000 or 6000 mgExamples for the brand; capsule count or scoop size rises with the amount
FormL-citrulline or citrulline malateDifferent compounds; input recalculated
FormatPowder or capsuleTablet, liquid and gummy are separate projects
Add-onsL-arginine, betaine, caffeineA second ingredient changes the unit weight, taste and claim wording

The pilot run confirms capsule fill at the chosen lot, scoop weight reproducibility and the taste of the flavored scoop in water.

Flavor Options

FormatSuggested FlavorsWhy
PowderUnflavored, watermelon, lemon-limeWatermelon and citrus flavors suit the mild sour note

Technical Status & Data Sources

ItemStatusDetails
Reference formulaNIH DSLDThe ingredient and amount come from a labeled product in the NIH DSLD (3000 mg on the label of CF003469; example DSLD labels 21744, 60215, 71782). The label names the ingredient as L-citrulline and lists no other ingredient; the free form is set.
SpecificationSet in formulationL-citrulline free amino acid at 3,000 mg per serving; assay, specific rotation, moisture, microbial and heavy-metal limits and method are fixed with the supplier. Unit size, fill weight and stability are set in formulation.
Data sourceNIH DSLDDSLD v9.4.0, downloaded 2026-01-10: 50,824 reference formulas merged from on-market labels with complete ingredient amounts. Counts show how labels are distributed.
Market reviewPer marketDose limits, labeling and claims are reviewed for each sales market before a finished product is developed.
ReferencesSources[1] Viribay A, Fernández-Landa J, Castañeda-Babarro A, et al. Effects of Citrulline Supplementation on Different Aerobic Exercise Performance Outcomes: A Systematic Review and Meta-Analysis. Nutrients. 2022;14(17):3479. DOI · PubMed

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