most peps are sold legaly in the chemists
they product range is generally short, when i was there i saw GH (lots of varieties, (kigs, hyge, unitrops, genotrops etc), melotan, igf, mod/cjc and ghrp-2/6
thats about all thats available from the right chemists, but the peps are very cheap, probably cheaper to buy online and have posted to where you live
as for legal issues, pretty sure there not illegal in thailand, and if they are it really doesnt matter since thai customs will let about anything through provided it doesnt smell like narcotics or look like a large firearm