Vitamin F d. Thiamine hydrochloride stability decreases above pH 5.0. Thiamine hydrochloride is destroyed by alkalies or alkaline drugs and by oxidizing and reducing agents.
Thiamine is unstable in presence of trace minerals.
Thiamine mononitrate is somewhat more stable than Thiamine hydrochloride in the presence of moisture, but not as stable in solution. Thiamine mononitrate is more stable and recommended for enriched flour, feed and vitamin premixes. Thiamine is involved in carbohydrate, fat, and protein metabolism. National Research Council - Vitamin Tolerance of Animals, 1987.