Fish Collagen Peptide，collagen is controlled under molecular weight 1000- 3000 Dalton by acid-base and enzyme digestion techniques. It's called small molecule peptide. Peptides are substances between amino acids and macromolecule proteins. Two or more amino acids form several peptide bonds through dehydration and condensation to form a peptide. Multiple peptides are folded to form a protein molecule. Peptides are precise protein fragments. Its molecule is only nanometer in size. Gastrointestine, blood vessel and skin are easy to absorb, and its absorption rate is much higher than that of macromolecule proteins.