The difference is quality. Pharm has better quality in terms of effectiveness, purity, dosage accuracy, cleanliness, etc...all of which, in my opinion, should NEVER be compromised just to save a few xtra dollars. Its not like theyre selling alcohol here where u can still get buzzed off some md2020...these chemicals are the foundation of ur body and how it works! Spend the extra dough, go pharm grade, period!