I have low ACTH of 6 (which is borderline low) and my cortisol is low normal. I tried Cordyceps and re-checked my ACTH and it was 398 (normal range 6-50)! I wonder if it really that effective or if something in cordyceps interferes with the essay... Unfortunately, I did not check my cortisol at the time. But I stopped and a week later ACTH was back to 6 - which seems to work better for me, high cortisol makes me feel worse.