Excellent. How does her response compare to, e.g., Mod GRF 1-29/Ipamorelin?
At 2 IU daily for a 28 y/o woman (especially if on oral contraceptives), it would really surprise me to see fat melting like snow due to the rhGH, as 1.8 IU is a common replacement dose for a 47 year old woman (mean).
I won't bother you with possible Hawthorne or Placebo effects being at play, as most people transpose some sort of judgment onto any such suggestion. Though being subject to these effects just means that someone is human.
But yes, certainly exceptions exist, though I just note that I commonly see guys in their 20s reporting results from 2 IU 5 on/ 2 off, which is absolutely impossible to attribute to the rhGH (i.e., this is less than replacement).
I absolutely believe your wife tolerates rhGH well if she has little side effects at 4 IU. Have you seen her IGF-I levels at 6 weeks+ at 4 IU? That'd be very interesting to see.