The only ingredient in Isocort is freeze-dried adrenal cortex. The claim that Isocort contains 2.5mg of cortisol does not come from the manufacturer...but from a doctor that uses it as part of his protocol. I will have to do some digging to find the link about it...can't remember which site I saw it on. It MAY be from the author who wrote Fatiqued to Fantastic...but I'm just not sure.
I have used both Drenamine and Isocort...no comparison! While Drenamine does contain additional ingredients that support the adrenals, it does not give the same boost to energy and ease of inflammation that Isocort does...cortisol helps with both. I think the difference may be in the way that the adrenal cortex is processed...by freeze-drying the cortisol is preserved within the adrenal cortex, hence it would not be listed as a separate ingredient. Cortisol...not to be confused with cortisone...is natural, not synthetic.
If you are already taking hydrocortisone you should not take additional cortisol...including Isocort. Too much supplemental cortisol will cause your adrenals to halt production of their own cortisol...and it can take a long while of weaning off the supplemental cortisol before your adrenals go back to producing their own.