Zinc-L-carnosine (polaprezinc)

What it is

Zinc-L-carnosine, called polaprezinc by its international nonproprietary name, is a one-to-one complex of zinc and L-carnosine. By mass it is about 23 per cent zinc and 77 per cent carnosine. Formula C9H12N4O3·Zn, molecular weight 289.60 (KEGG D01611). It was invented by Hamari Chemicals and developed with Zeria Pharmaceutical (Experimental and Therapeutic Medicine 2021).

As a medicine

Japan approved Promac granules for gastric ulcer on 1 July 1994. The usual adult dose stated in the Japanese prescribing information is 75 mg twice a day (PMDA interview form). It is also approved in South Korea and China.

As a supplement

In the United States the PepZin GI ingredient was cleared for sale as a new dietary ingredient in 2002 (FoodNavigator 2002). In the European Union, EFSA’s 2022 safety opinion concluded that zinc-L-carnosine is absorbed and supplies zinc, but that its safety as a novel food “has not been established” because the substance was not sufficiently characterised (EFSA Journal 2022). In Australia, polaprezinc is a permitted active ingredient in listed medicines for oral use, capped at 34 mg of zinc a day from polaprezinc. See Status in Australia.

The trials

The published trials are in the stomach and gut: gastric ulcer against rebamipide (Shen 2022), as an addition to Helicobacter pylori triple therapy (Mahmoud 2022 meta-analysis), aspirin-related small-bowel injury (Watari 2013), oral mucositis during cancer treatment (Doi 2015; De Francesco 2026 meta-analysis) and exercise-induced gut permeability (Davison 2016). A laboratory and small human study of its action on the gut lining is at Mahmood 2007. In dogs, an ex vivo study of gastric mucosa found no protective effect (Hill 2012).

A zinc-L-carnosine result cannot be assigned to carnosine alone or to zinc alone unless a trial compared the two, and few have. See Gut.