GHRP/GHRH combo. I dose at saturation level each day should exert a positive impact on BMD levels, provided you are using clinical grade peptides. The vast majority of people are not. 2-3 doses per day may exert a further positive impact however, somewhat paradoxically, when you get into 5 or more doses per day this effect reverses, essentially just as it does with high dosing rGH.
This is all in regards to BMD, not bone size. If youre fully grown your not gonna grow any bones with peptides.