After findinga great source for GH at $2.30 per IU my doc did some research to discover that the potency of GH can vary. Apparantly GH comes in .2, .4, and .6 mcg per iu potencies. My doc emailed two seperate Chinese suppliers and found that the one that sells for $3.75 per iu is .6 and the one that sells for $2.30 per iu is .4. This means that getting an equivelent dosage of the cheaper variety means that you must take 33% more. Although the $2.30 variety is 34% cheaper, it is 33% less potent. Not worth the 1% savings! Buyer Beware!