example: based on nutrition labels, if you put 20gram collagen in your coffee, which is 18g protein, and then also eat eggs, bacon, and toast for another 18g protein, you’re at 36g protein in one sitting.
Based on my understanding, the body won’t get to utilize more than 30g protein/meal, so would any of the collagen potentially not get absorbed as a result since it’s also a type of protein? This is a moderate example, but the question stands if you ate a 40-50g protein in one sitting.
Your pancreas secretes the enzymes that digest protein and it knows via signalling from the gut when that has all be consumed digesting protein. The 30g postulation is based on a typical diet but if you are continuously consuming more then your pancreas will just produce & secrete more of the enzymes so you will have an upper limit higher than 30g.
If you regularly eat 30g a meal your body will adapt to 30g a meal, if you throw in 100g randomly you won’t digest most of it. If you regularly eat 100g a meal your body will adapt to that.
As a side note be careful of wild claims about collagen efficacy. Your body can use peptides to shortcut protein synthesis but its not clear if this really has an impact on skin health as the studies so far haven’t had good controls, most of the purported benefits could just be from eating better & staying hydrated.