IGF-DES is a shortened version of the natural growth factor IGF-1: the same protein with its first three building blocks removed, leaving about sixty-seven. The 'DES' in the name simply marks that removal. Like other proteins of its kind, it is made recombinantly.
It is offered as one production batch, with per-lot analysis you can pull up by lot number.
The detail to keep in view is precision. Several sources give slightly different masses for this protein — a spread of only a few units — most likely the same 'how are the internal bridges counted' ambiguity seen in related growth factors. Rather than smooth that over, the identity record keeps a primary value and discloses the spread.
For laboratory research use only. Not for human or veterinary use.