Protein hydrolyzates are an important part of the human diet. Often, they are prepared from milk, soy, or collagen. In the present study, four different collagen hydrolyzates were tested, varying in the average mol. weight and the animal source. Three types of samples, the dissolved start products, in vitro generated dialyzates (containing the digested components that are potentially available for small intestinal absorption), and human serum collected after product ingestion, were analyzed using LC-MS to compare the state of the hydrolyzates before and after absorption, i.e., uptake into the blood. It was found that the composition of the collagen hydrolyzates prior to and after ingestion was highly complex and dynamic, which made it challenging to predefine a strategy for a targeted anal. Therefore, we implemented a new anal. approach to first map hydrolyzate data sets by performing non-targeted LC-MS anal. followed by non-targeted and targeted data anal. It was shown that the insight gained by following such a top down (data) anal. workflow could be crucial for defining a suitable targeted setup and considering data trends beyond the defined targets. After having defined and performed a limited targeted anal., it was found that, in our exptl. setup, Hyp-Gly and especially Pro-Hyp contributed significantly as carrier to the total Hyp increase in blood after ingestion of collagen hydrolyzate.