I had see somewhere if you frozen peptides it's okay if you don't have unfrozen and re frozen but the best it's 2 years in the freezer (I don't have the article sorry)
They should be fine in the freezer for a couple years at least.
Don't know how true this is but I have heard that if there is any moisture in the vials of peptide, it will cause ice crystals to form within the powder and can degrade it somewhat. I personally keep my peptides in the fridge.