The last thread got me to thinking:

My libido, while always present, seems to vary cyclicly, approximately on a monthly cycle, but not exactly.

I usually hobby weekly, and almost always have two ejalculations when I do, but some weeks I get horny enough to want to masturbate several times during the week, and other weeks I have little interest in it.

Do men's hormones vary during the month the way womens' do, and would that account for the variation I find in my libido?