The actual collagen is not recommended to drink on an empty stomach, because if you drink collagen on an empty stomach, it will cause the following adverse reactions to your body: 1, it will seriously stimulate the mucous membrane of the gastrointestinal tract resulting in excessive secretion of gastric acid, and if you have a history of chronic gastritis and gastric disease, it will aggravate the occurrence of chronic gastritis, and it will produce erosion of the gastric mucosa, or excessive secretion and reflux of gastric acid, which will cause erosive gastritis, atrophic gastritis and bile reflux gastritis. The actual collagen is a protein that will cause a certain amount of burden and load on the kidneys when drunk on an empty stomach. 3, drinking collagen on an empty stomach for lactose intolerant patients will seriously lead to diarrhea and a significant increase in intestinal dynamics and secretory diarrhea, etc. Therefore, collagen is recommended to be taken slowly after 30 minutes after meals. take it.