Selecting the right peptide source requires a focus on molecular weight and purity. For optimal skin absorption (bioavailability), prioritize peptides with a molecular weight below 1000 Daltons. Ensure the supplier provides a Certificate of Analysis (COA) for every batch, verifying a purity level of at least 98%. Additionally, check for solubility characteristics; high-quality glow peptides should dissolve clearly in water without precipitation to ensure stability in end-products like serums or drinks.