Synthesis routes compared

Solid-phase peptide synthesis (SPPS) builds the chain on an insoluble resin, washing away reagents between couplings. It is the standard route for cosmetic and research peptides up to roughly 40 residues. Its weaknesses are aggregation during chain growth and the cost of purification for long or hydrophobic sequences.

Liquid-phase synthesis is used where scale justifies the development cost, or where the chemistry is incompatible with a resin. It requires more process development but produces less waste per kilogram at large volumes.

Hydrolysis — enzymatic or acid — breaks a whole protein into fragments. You get a reproducible distribution rather than one sequence, which is exactly what food-grade collagen and soy peptides are.