Collagen supplements are popular among those who want to reap the beauty benefits, such as firmer skin and stronger nails; however, there is little concrete evidence that they actually work. Some evidence suggests collagen may alleviate joint pain. Other research supports collagen's ability to increase skin elasticity and hair strength and growth. There is less evidence supporting the use of collagen for nail strength, but it is possible that collagen supplements might be beneficial. Regardless of these benefits, some collagen powders are significant sources of protein and can be used as protein powders.