on product side:
the main reason should be purity and endotoxin. endotoxin must be <5EU,which is not difficult to control. then purity, more dose in one vial is more difficult to make high purity, before , the purity of my gh was 96-97%, now we reach at least 98%,sometimes 99% ,which is good as generic. the purity os pharma is at least 99%. once we control those 2, the product itself shouldn't give much red welts.
on personal side:
1, The red welts are an auto immune reaction. Its the body recognizing the HGH as a foreign substance and destroying it. If the red welts disappear it just means the body has adjusted
2, high concentration. my gh is 24iu per vial, in the market, its 10iu vial, so u put 1ml into 24iu vial, its high concentration, its more possibility to give red welts, just need to put more water.
3, use bac water.
4, clean well the pin spot everytime before u pin.
etc etc