Natural Progesterone Info
This site has a lot of information about progesterone but the navigation is a little weird -- you have to use the left navigation bar, roll-over HORMONES, the over SEX HORMONES, then over PROGESTERONE and you can click on the links that show up there. The directions they give are in contradiction with other information I've seen where you should only use it post ovulation (whenever ovulation occurs).http://thecompounder.com/hormonesprogesteronefaq.html
I have this article bookmarked from this site linked which you might find helpful, it is by Dr John Lee and it talks about why transdermal dosing of progesterone is preferable. Note that it says too much progesterone can "[result] in rather high levels of allopregnanolone and the woman becomes rather anesthetized by it, a state that is sometimes confused with depression" -- so that would be a side effect if too much is taken.
LETTER TO A COMPOUNDING PHARMACIST
Delivery of steroid hormones.
You can learn more about progesterone by reading What Your Doctor May Not Tell You About Pre-Menopause(also by Dr Lee)