Many people believe that you should take a collagen supplement first thing in the morning, as your body is better able to break down proteins like collagen when you take them on an empty stomach. However, this is actually a myth—it doesn't really make a difference whether you take collagen on a full or empty stomach.
Firstly, "The bulk of the breaking down of proteins actually happens in the small intestine, so full stomach, half-full stomach, or empty stomach—there will be little difference," registered dietitian Scott Keatley, R.D. once told mbg.
Secondly, as mbg's vice president of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN explains: "Hydrolyzed collagen peptides are exactly that, hydrolyzed (aka broken down) into peptides. Thus, once the protease and peptidase digestive enzymes in the small intestine interact with these collagen dipeptides and tripeptides, these tiny peptides and constituent amino acids are efficiently digested and absorbed by our gut—to then be utilized throughout the body, for benefits like skin hydration and elasticity."*
On the flip-side, some people claim that you should take collagen supplements at night so that your body will process it during the REM cycle (a recovery period during your sleep), making it more effective in the body. Fact check: There’s no evidence to suggest that. “Think of collagen as more of a general in-your-system-type supplement," says Keatley. And when collagen enters the body, it goes through the stomach and eventually reaches the small intestine.