Not that I give credence to anything anyone ever says anymore, but what is the S2 clause?
Not sure if you wanted the legal guff or a basic list of what its for
Its a set of guidelines, clarifications and a prohibited list of substances/Peptides that vary or may have been modified for diffetent effect that basicly promotes gh via pituitary gland stimilation which may ( lol ) or may not control many systems in the body, elevated naturally produced HGH > Fatloss, muscle growth, insulin sensitivity..
Very grey area science which many believe are inferior to synthetics as far as impact which opens a debate of should they be considered legal in sport as recovery... much more trials need to be done to determine saftey (remember many are prescribed)
Whats interesting is they are legal in some sport such as the UFC...
Thats a basic summary... it get much more interesting delving into how they work

id take 1
or 2 of them for some of the health benifits alone if proven safe...
S2. Peptide Hormones, Growth Factors and Related Substances
If a Substance or Method is not defined in this list, please verify with your Anti-Doping Organization.
The following substances and their releasing factors are prohibited:
Erythropoiesis-Stimulating Agents [e.g. erythropoietin (EPO), darbepoetin (dEPO), hypoxia-inducible factor (HIF) stabilizers, methoxy polyethylene glycol-epoetin beta (CERA), peginesatide (Hematide)]
Chorionic Gonadotrophin (CG) and Luteinizing Hormone (LH) in males
Corticotrophins
Growth Hormone (GH), Insulin-like Growth Factor-1 (IGF-1), Fibroblast Growth Factors (FGFs), Hepatocyte Growth Factor (HGF), Mechano Growth Factors (MGFs), Platelet-Derived Growth Factor (PDGF), Vascular-Endothelial Growth Factor (VEGF) as well as any other growth factor affecting muscle, tendon or ligament protein synthesis/degradation, vascularisation, energy utilization, regenerative capacity or fibre type switching
and other substances with similar chemical structure or similar biological effect(s).