since no one has answered here, ill let you guys know what i found out. i talked to someone who is a clinical bacteriology student. he said that the nacl will keep the hcg bacteriostatic longer. but timeframe isnt a main concern with people using hcg for pct needs. in pct we go thru it pretty fast, i used a 5000 iu kit in a week, and i took hcg through out cycle. if you dont use it thru the cycle, youll go thru it even faster.