NADPH is needed for the reductive biosynthesis of fatty acids and steroids, and therefore, HMP occurs more actively in the tissues concerned with lipogenesis, for example, adipose tissue and liver. NADPH is used in the synthesis of amino acids involving the enzyme glutamate dehydrogenase.

There is a continuous production of H₂O₂ in living cells, which is chemically damaged unsaturated lipids, proteins, and DNA. This is prevented to a large extent through antioxidant reactions involving NADPH, glutathione-mediated reactions of H₂O₂.

Microsomal cytochrome P₄₅₀ system brings about detoxification of drugs by hydroxylation reactions, involving NADPH. Phagocytosis is the engulfment of foreign particles inducing microorganism, carried out by WBC.