Paraxanthine

Paraxanthine is traded essentially as a single specification, a food or supplement grade crystalline powder at 98 to 99 percent minimum assay, with the related methylxanthines caffeine, theophylline and theobromine controlled as individual impurities because they are the substances most likely to be carried through from the synthesis. Buyers specify a residual solvent profile appropriate to the route used and, where the material is made by fermentation or biocatalysis, a microbiological set as well.

The practical variation is physical rather than chemical. Standard crystalline material, micronised grades milled to a finer particle size for faster dissolution in cold liquids, and granulated grades for direct compression tabletting are the forms usually stocked. Anhydrous material is the norm. Some suppliers also offer the ingredient as a branded, dossier backed grade tied to a specific safety review, which is a documentation distinction rather than a difference in the substance.

In the United States paraxanthine is marketed as a dietary ingredient and as a food ingredient on the basis of generally recognised as safe conclusions supported by toxicology and human tolerability studies, and a GRAS notification for its use in beverages and supplement categories has been submitted to the FDA under the agency's voluntary notification programme. It is not the subject of a standing food additive regulation, so its lawful use rests either on a GRAS determination for the specific conditions of use or, for supplements, on new dietary ingredient notification. Products containing it are subject to the general labelling requirements for dietary supplements and to the stimulant labelling expectations that apply to caffeine and its relatives.

In the European Union paraxanthine has no history of significant consumption as an isolated substance before May 1997 and therefore falls under the Novel Food Regulation, Regulation (EU) 2015/2283. It requires authorisation and entry in the Union list before it may be placed on the market as a food or food supplement ingredient, and it is not currently authorised. Codex Alimentarius has no commodity or additive standard for the substance, and JECFA has not evaluated it; the relevant international reference material is the wider body of methylxanthine safety assessment carried out for caffeine. National rules on stimulant labelling and on maximum stimulant content in food supplements apply in several member states independently of the novel food position.