Depends what you mean with “collagen supplements”. If you mean the ones with proline and glycine then yes they stimulate collagen production but you have to keep in mind collagen is the connective tissue of every tissue in the body. Skin,cartilage,bone,muscle etc they’re differ from type 1 collagen to type 4 collagen. So not all of your collagen liquid for example will be transferred to increasing collagen synthesis in the skin. What I recommend you to get is beef gelatin powder,not collagen liquid,collagen powder,collagen capsules or whatever. Beef gelatin is way cheaper and also serves more bioavalibility and is a good source of protein.