L-Carnitine

Grades and forms

L-carnitine free base (161.20 g/mol) is the reference form for a carnitine label claim. Before assay correction, 1 mg of powder gives 1 mg of L-carnitine. Its main handling issue is moisture uptake. That is why many tablet makers use L-carnitine L-tartrate instead, which contains 68.2 % L-carnitine by mass. The carnitine nutrient guide covers all forms side by side.

Manufacturers buy L-carnitine in bulk as a white crystalline powder. Four points usually decide the grade and physical form:

• Format: liquids and drinks tolerate the base well, while compressed tablets favour a less hygroscopic form.
• Moisture control: your plant’s humidity control and packaging line determine how practical the base is.
• Release specification: your QA team may require food grade or a pharmacopoeia grade.
• Optical purity: only the L-enantiomer is used, so check how the specification controls it.

SoleChem is a direct supplier of L-carnitine, not its manufacturer. It sends the specification sheet and certificate of analysis with each quote, so state the grade you need in the quote form.

EU regulatory status

L-carnitine is neither a vitamin nor a mineral. Annexes I and II of Directive 2002/46/EC therefore do not list it. In food supplements it is treated as an “other substance”. Member states may regulate these through national rules.

Where such rules exist, they can differ. A member state may set a maximum amount per daily portion, require notification before sale, or keep a list of permitted substances. Check with the competent authority of each target market before launch.

Regulation (EC) No 1925/2006 gives the Commission a procedure to restrict or prohibit other substances in foods. Check Annex III of the consolidated text for any entry concerning carnitine.

Novel food status under Regulation (EU) 2015/2283 must be confirmed for each form you use. Check the Union list in Implementing Regulation (EU) 2017/2470. The novel food guide explains how status is established. For label wording and any planned claim, see the labelling guide and the health-claims guide.

Formulation notes

L-carnitine base is strongly hygroscopic and takes up water readily from humid air. Open containers can cake or turn sticky. Weigh and blend in low-humidity rooms, reseal part-used drums at once and choose moisture-barrier finished packaging.

Capsules. The base can be filled into HPMC capsules or gelatin shells. A flow aid such as silicon dioxide helps fill-weight consistency. A hygroscopic fill can draw water from the shell, so run stability trials on the finished capsule. See ingredients for capsules.

Tablets. Moisture pick-up makes the base hard to compress consistently. L-carnitine L-tartrate is the common choice for tablets.

Powders and liquids. L-carnitine dissolves readily in water, which suits drinks, shots and stick packs. For dry blends, use sachets with a moisture barrier. See ingredients for powders and sports nutrition.

Label arithmetic. L-carnitine L-tartrate is a 2:1 salt: two L-carnitine molecules per molecule of L-tartaric acid. Its 472.5 g/mol molar mass applies to that unit. The carnitine share is 2 × 161.20 ÷ 472.5 = 68.2 %. To declare 500 mg of L-carnitine you need about 733 mg of the tartrate. To declare 1,000 mg you need about 1,466 mg. Correct these figures for the assay on the certificate of analysis, then add any overage with the overage calculator.

How L-carnitine compares to other forms

Values are calculated from molar masses, before assay correction and overage. Acetyl-L-carnitine is normally declared as acetyl-L-carnitine rather than as L-carnitine. The L-carnitine vs acetyl-L-carnitine comparison covers that choice. Other actives in this group are listed under coenzymes and longevity actives.