I’m 19 years old - not sure if you consider that an adult...but I thought I’d reply too. I take 25mg a day. And it seems to be fine for me. 20mg sounds a little low to me - but I’m not sure how low anyone can go.  I’ve always been between 25-30.

I’m not sure what to tell you really. But yeah, what symptoms do you have on the 20mg?