I don't know, it seems for me that the more I lift and the more caffeine I ingest, the smaller it looks. Stress plays a part. It's the opposite of when you're drinking and you are relaxed. I feel like on days I'm lifting, or soon thereafter, my erection quality suffers. I didn't notice any increase from steroids, and my IGF is already naturally high.
Did you check your endogenous Cortisol levels? sounds like a cortisol issue
No I haven't, but you might be onto something. Is there anything that can be done if it is high?
diet changes (usually more clean carbs at the right time, like right before bed and first thing upon waking) , more sleep/rest , less stress .. and of course there are always drugs that suppress cortisol (Cytadren, Winstrol, Insulin, etc)