Progesterone...
NO to synthetic, synthetic can in most cases have some androgenic reactions (my shoulders broadened and grew thicker hair).
Bio ID on the other hand helped breast tissue, normalize my estrogen levels, stabilize mood swings, and help distribute fat more evenly.
I cycle 15-30th of every month.
When I don't take it I feel more bloated personally.
These are just my observations. Everyone is different obviously...