Alpha Lipoic Acid

Alpha lipoic acid, also called thioctic acid, is the organo-sulphur carboxylic acid C8H14O2S2 (CAS 1077-28-7, molecular weight 206.33): a pentanoic acid chain terminating in a strained 1,2-dithiolane ring, systematically 5-(1,2-dithiolan-3-yl)pentanoic acid. Standard commercial material is the racemate, an approximately equal mixture of the R and S enantiomers, produced by chemical synthesis rather than by extraction. Thovek's default grade assays not less than 99.0% by HPLC on the dried basis. USP publishes an Alpha Lipoic Acid monograph and reference standard for dietary supplement use, and the European Pharmacopoeia carries Thioctic acid with its own reference standard, so buyers can nominate either method on the purchase order. The substance is a yellow needle-like crystal or pale yellow crystalline powder with a faint sulphurous note, melting at 60-62 °C. That melting point is low enough to matter commercially: drums held in an uncooled warehouse will soften, cake and in the worst case fuse, and the material is also light sensitive and prone to polymerisation on heating, so it should be processed at ambient temperature and kept dark. It is practically insoluble in water and dissolves in methanol, ethanol, diethyl ether and chloroform, which pushes most formulators toward capsules, tablets and oil suspensions rather than aqueous liquids. Where water solubility is essential, sodium R-lipoate (CAS 176110-81-9) is the practical route; where only the naturally occurring enantiomer will do, R-(+)-alpha lipoic acid (CAS 1200-22-2) is quoted separately and melts lower still, around 46-49 °C. Because the molecule is synthesised rather than extracted, alpha lipoic acid carries no animal, dairy, egg, soy, fish, crustacean, nut, wheat or gluten input, and is suitable for vegan and vegetarian ranges; kosher and halal documentation is available. The sulphur sits in the dithiolane ring as a structural feature and is not a sulphite, so it does not attract a sulphite declaration. Where the finished form is a hard capsule or softgel, the shell determines the label: gelatin shells are typically bovine and remove vegan and vegetarian status, whereas HPMC and pullulan shells retain it. Every consignment ships with a COA covering HPLC assay and related substances, melting range, heavy metals by ICP-MS against USP <2232>, residual solvents to ICH Q3C and microbiology to USP <2021> and <2022>, alongside allergen, GMO and BSE/TSE statements.