Are you referring to this....
Long chain esters, such as Cypionate, Decanoate, Enanthate, etc. possess a much weightier molecular weight than short chain esters. Consequently, on a mg for mg basis, you are receiving far extra mg of steroid in a short estered compound as opposed to a large estered compound. As an example, there exists a larger amount of mg of Testosterone in 100mg of Testosterone Propionate than 100mg of Testosterone Enanthate. This is due to the shorter, and therefore lighter weight of the Propionate ester in comparison to the larger and therefore much heavier Enanthate ester. Many individuals just do not realize this, and should always consider this factor as one of the factors involved in the decision making process concerning which ester variant of any given compound to use during a cycle.
Without complex mathematical explanation as to how much of the ester weight is determined to occupy in a given compound, here is a list of some of the most common esterified injectable compounds and how much free hormone is left in a given amount of the compound (standardized to 100mg),
100mg Testosterone Suspension (un-esterified Testosterone) = 100mg Testosterone
100mg Testosterone Acetate = 83mg Testosterone
100mg Testosterone Propionate = 80mg Testosterone
100mg Testosterone Isocaproate = 72mg Testosterone
100mg Testosterone Enanthate = 70mg Testosterone
100mg Testosterone Cypionate = 69mg Testosterone
100mg Testosterone Phenylpropionate = 66mg Testosterone
100mg Testosterone Decanoate = 62mg Testosterone
100mg Testosterone Undecanoate = 61mg Testosterone