Thiochrome, a natural oxidation product and metabolite of thiamine, is a selective M4 muscarinic receptor of acetylcholine (ACh) affinity enhancer. Thiochrome has neutral cooperativity with ACh at M1 to M3 receptors[2].In Vivo: Thiochrome can increase the intensity of the reproduction process of the representatives of one-cell organisms worms, crustaceans, insects and fishes.