Carnitine (L-Carnitine) bulk powder for formulators

Carnitine is not a peptide. It is a small quaternary-ammonium betaine, L-carnitine, that Pepti, Guangzhou produces on the same line and supplies on the same terms as its peptide raw materials: bulk powder from 5 g, cold-chain shipping, a lot certificate of analysis with the shipment and a safety data sheet on request. Scalp-tonic, shampoo and body-care formulators ask for it under the INCI name Carnitine, and their first question is usually which carnitine is on offer, because the inner salt, the tartrate and the hydrochloride are listed separately and differ in carnitine content per gram.

This page covers the identity of the material Pepti supplies, the inner salt with CAS 541-15-1, and the two handling traits that shape every bench trial with it: it is strongly hygroscopic, and it is a zwitterion that stays charged across the whole cosmetic pH range.

Identity: inner salt, tartrate or hydrochloride

Three materials are sold under the name L-carnitine, and a formulator's paperwork should name the right one.

• L-Carnitine inner salt, CAS 541-15-1. The free zwitterion: INCI Carnitine, PubChem CID 10917, formula C7H15NO3, molecular weight 161.2 g/mol. This is the material Pepti supplies and the number printed on its documents.
• L-Carnitine L-tartrate, CAS 36687-82-8. A salt of two carnitine molecules with one tartaric acid. It has its own INCI entry, is much less hygroscopic, and contains less carnitine per gram. Catalogues often print its data under a plain L-carnitine heading.
• L-Carnitine hydrochloride, CAS 6645-46-1. The HCl salt, again a separate INCI entry, and acidic in solution.

A listing with a molecular weight well above 161.2 g/mol is describing a salt. Only the L enantiomer is in scope. The sequence field in the identity table is a dash, as for every non-peptide active here.

Appearance, solubility and handling

The inner salt is a white crystalline powder and it is strongly hygroscopic. Left open on a bench it takes up water from the air, clumps, and can eventually turn to a syrup. Keep the sealed container at −20 °C with desiccant for long-term storage, hold working stock at 2–8 °C, and open a cold container only after it has warmed up, so that condensation does not land on the powder. Weigh quickly, close at once, and use the water content on the COA when calculating the carnitine delivered.

Solubility is the opposite problem to most actives on this site. Carnitine is very soluble in water, soluble in ethanol and insoluble in oils. It goes into the water phase without co-solvents or heat, at whatever point in the process suits the formulator, and because the molecule has no chromophore it adds nothing to the colour of the finished product.

What the published literature reports

The topical literature on carnitine is small. Foitzik and colleagues cultured human scalp hair follicles with L-carnitine-L-tartrate and reported a moderate stimulation of hair shaft elongation and a prolonged anagen phase in that in-vitro organ-culture model; the authors suggested that topical application deserved further study (Foitzik K, Hoting E, Förster T, Pertile P, Paus R. Exp Dermatol, 2007). The study used the tartrate salt rather than the inner salt described on this page, and an organ-culture result is not a claim for a finished product.

PubChem lists the inner salt under the title (-)-Carnitine with formula C7H15NO3 and molecular weight 161.2 g/mol (PubChem CID 10917), and the European CosIng database lists the ingredient under the INCI name Carnitine.

That is the extent of what this page says about function. Claims for a scalp or body-care product are the brand's to substantiate in its own market.

Formulation notes for the bench

These are chemistry notes, not efficacy notes.

• Zwitterion across the range. The quaternary ammonium is permanently positive and the carboxylate is deprotonated above its low pKa, so carnitine carries both charges in any base from mildly acidic to neutral. Its solubility barely changes with pH, and it does not act as a buffer.
• Water phase, no co-solvent. Add it to the water phase. It is compatible with glycerin, glycols, anionic and amphoteric surfactants and the usual water-soluble thickeners.
• Heat and alkali. Under strong heat and high pH carnitine can lose water to form crotonobetaine. Keep processing below 40 °C where practical and avoid strongly alkaline bases.
• Hygroscopic bulk. Pre-weighed sub-lots in sealed containers avoid repeated opening of the bulk jar.
• Preservation. Carnitine is a nutrient in the water phase. Preservative efficacy is confirmed by challenge test in the buyer's own base.
• Tartrate substitution. A formula developed with the tartrate cannot take the inner salt weight for weight. Recalculate for the carnitine content and for the missing tartaric acid, which changes the pH of the water phase.

Use level is the formulator's decision, set from their own stability and compatibility work.

Specification and documents for this material

Each lot comes with a certificate of analysis that reports HPLC purity, mass-spectrometry identity against the expected molecular weight, appearance, water content, and the storage and retest statements. Water content matters more for this material than for most on the site. A safety data sheet in the standard 16-section format is available, and both documents name Pepti, Guangzhou as the manufacturer. If a specification calls for an optical-rotation or chiral check, request it on the RFQ.

No public batch record for carnitine is listed in the Pepti COA library yet; the lot COA is issued with the shipment. For orientation, the public records Pepti publishes for its other compounds currently fall between 98.4% and 99.8% HPLC purity.

Public batch records

No public batch record is listed for this compound in the manufacturer's library yet. The lot you receive carries its own COA with HPLC purity, MS identity and lot number; ask for the current lot's COA with your quote. The library itself is at peptioem.com/coa.