That’s an interesting question. Hair is mainly protein, but it also contains some lipid. The lens of the eye is mainly protein, but it also contains some carbohydrate molecules. Muscles are rich in protein as well. The actin and myosin filaments in a muscle are protein, but the muscle as a whole also contains carbohydrates and fatty acids.
Our fingernails and toenails are made of dead cells containing a protein called keratin. The production of a large quantity of keratin in living cells is known as keratinization. Keratinization happens in some other parts of the body besides the nails. The keratin replaces the contents of the cells. I don’t know how many of the chemicals from the living cells remain in nail cells that have been keratinized, however.