L-Carnitine

Single-ingredient L-carnitine reference formula at 500 mg per serving, developed as a capsule or tablet.

L-Carnitine is a reference formula for brands building a single-ingredient vitamin-like nutrient product at a default amount of 500 mg of carnitine per serving. L-carnitine is the only active ingredient, so the development work centers on the carnitine form (free base, tartrate or another salt), the weight of salt that carries 500 mg of carnitine, and the hygroscopic behavior of the raw material in a solid unit.

Capsule is the lead format because 500 mg of carnitine from the free base fits one large capsule, while a tablet carries the tartrate salt in a compression system. Options of 250 and 1,000 mg sit beside the default, and the amount is a decision for the brand and its market review.

Ingredient Composition

IngredientPer ServingRaw Material FormAlternative Form (same amount of active)
L-Carnitine500 mg (default amount)L-carnitine free base (levocarnitine), specified on a carnitine basis; 500 mg carnitine per servingL-carnitine L-tartrate, with the input recalculated to 500 mg of carnitine

Amounts are stated as mg of carnitine. L-carnitine is C7H15NO3, 161.20 g/mol (PubChem CID 10917); L-carnitine L-tartrate is C18H36N2O12, 472.5 g/mol (CID 57349413) and holds two carnitine units, so it is 68.2% carnitine by weight and 500 mg of carnitine needs about 733 mg of the salt. The label basis, carnitine or salt, is stated in the specification.

Intended Benefits & Formula Rationale

This formula is designed for products positioned around daily carnitine intake and metabolic nutrition. L-carnitine is included as the single active so that the form, the amount and the unit can be set without interaction with other actives.

Intended Benefit DirectionKey IngredientsFormulation Rationale
Daily carnitine intakeL-CarnitineIncluded as a vitamin-like substance whose clinical evidence on body weight has been described as inconsistent across trials [1]. Evidence: Referenced
Weight management nutritionL-CarnitineA meta-analysis of 37 randomized trials reported a lower body weight (-1.21 kg), BMI and fat mass with carnitine supplementation and no significant effect on waist circumference or body fat percent [1]; an update of 43 trials found a similar result with body weight lower by 1.13 kg [2]. Evidence: Mixed

A stated amount of one active keeps the specification short. The two reviews pool many dose levels, so the amount, the claims and the target market are brand decisions reviewed for each sales market.

Available Formats

The carnitine reference formula is built for a capsule version and a tablet version; counts per serving are design choices that the brand can adjust.

FormatUnitPer ServingPack SizeOther Ingredients (typical)Suitability
Capsule1 capsule500 mg60 or 120 capsulesGelatin shell, stearic acid, talc, magnesium stearate, silicaLead format; large single capsule
Tablet1 tablet500 mg60 or 100 tabletsDibasic calcium phosphate, microcrystalline cellulose, croscarmellose, stearic acid, film coatCoated unit that limits moisture pickup

Raw Material Input & Fill (Design Estimate)

Design estimates. The input is the carnitine amount divided by the carnitine content of the raw material at an assumed 100% assay: the free base needs 500 mg for 500 mg of carnitine, and the tartrate at 68.2% needs about 733 mg.

FormatRaw Material Input per UnitDesign FillBalance for ExcipientsVerification Before Scale-Up
Capsule500 mg free base600 mg per capsule100 mgFill weight variation, flow, moisture, content assay of carnitine
Tablet733 mg tartrate900 mg tablet weight167 mgHardness, disintegration, coating integrity, content assay of carnitine

Powder, liquid and gummy versions are separate projects, because a hygroscopic amino-acid-like raw material needs its own moisture and taste work in those formats.

Formulation Considerations

Hygroscopic raw material. Free-base carnitine picks up water quickly, which causes clumping in blends and softening in tablets. Blending humidity, a coating or a desiccant in the bottle are set early, and the tartrate salt is the more stable alternative.
Salt versus free base. The tartrate carries 68.2% carnitine, so the same 500 mg of carnitine needs about 233 mg more raw material and a tablet of about 900 mg. The form is fixed together with the unit size and the cost per milligram.
Label basis. The label amount is carnitine, not the salt. The specification states the assay of the raw material, and the content assay of finished units is run as carnitine.
Evidence and tier. The reviews in [1] and [2] report small average changes with wide variation, so claims on a finished product are reviewed per market, and the dose limit for each sales market is checked before a product is developed.

Customization Options

Brands adjust the amount per serving, the carnitine form, the format and the coating.

ParameterRangeNote
Amount per serving250, 500 or 1000 mgOptions for the brand; unit size scales with the tier
Carnitine formFree base or tartrateTartrate needs about 47% more raw material per unit of carnitine
FormatCapsule or tabletPowder, liquid and gummy are separate projects
Pack size30 to 120 unitsSet by the brand
Add-onsChromium, green tea extract, vitamin B complexA second active reshapes the fill weight and the specification

The pilot run confirms moisture behavior and flow of the carnitine blend, tablet hardness and coating integrity, capsule fill weight, and the content assay of the first units against the labeled amount of carnitine.

Technical Status & Data Sources

ItemStatusDetails
Reference formulaNIH DSLDThe ingredient and amount come from a labeled product in the NIH DSLD (500 mg on the label of CF000885; example DSLD labels 6390, 6866, 8083). The label names the ingredient as L-carnitine; the free base is set as the form.
SpecificationSet in formulationL-carnitine free base, 500 mg per serving; assay, water content and residue 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] Talenezhad N, Mohammadi M, Ramezani-Jolfaie N, et al. Effects of l-carnitine supplementation on weight loss and body composition: A systematic review and meta-analysis of 37 randomized controlled clinical trials with dose-response analysis. Clin Nutr ESPEN. 2020;37:9-23. DOI · PubMed<br>[2] Askarpour M, Hadi A, Miraghajani M, et al. Beneficial effects of l-carnitine supplementation for weight management in overweight and obese adults: An updated systematic review and dose-response meta-analysis of randomized controlled trials. Pharmacol Res. 2020;151:104554. DOI · PubMed

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