I have recently been struggling with different symptoms the biggest being a massive weight gain of 16lbs in 4 weeks. My doctor was testing me for cushings syndrome as we are stumpted on what could be causing it. My thyroid was checked and it came back in the normal range. My doctor ordered the following tests: Dexamethasone, serum, cortisol AM, ACTH Plasma tested. My doctor had me do the dexamethasone suppression test. I had my levels tested when she said at 8am and my cortisol came back below range at 0.8. The range was 4.0-22.0. Could this very low level explain the weight gain? What does this low level mean?