A reverse calculator can help figure out the exact amount of bac water needed based on the target draw. I usually add 2-3 ml of bac water unless the peptide tends to sting, in which case I dilute more. There are also cases like very small doses where different volumes make sense. For ordinary peptides I try to land around 20 units per dose for easier measuring. Insulin syringes top out at 30, 50, or 100 units, and those volumes all appear acceptable for subq use.
Just wondering how to handle higher concentration peptides per vial. The usual approach is to add 1-2 ml of bac water per 10 mg of compound. That works fine with 10 mg or 20 mg vials, for example 1 ml into a 10 mg vial so a 2 mg dose is 20 units on a 1 ml syringe. With a 40 mg vial though, even adding the full 3 ml means a 10 mg dose comes to 60 units, which feels like a lot. At the same time the ratio drops below 1 ml per 10 mg. Two questions come up: what is the maximum volume that can be injected subcutaneously at one time, and is it a problem to reconstitute with less than 1 ml of bac water per 10 mg?