Progesterone is a naturally occurring hormone in human bodies, whereas progestin is a synthetic version. There are about 8+ different progestins used in birth control pills, hormonal IUDs, birth control implants, birth control rings. Some of them are: norgestrel, levonorgestrel, norethindrone, norgestimate, desogestrel, drospirenone, etonogestrel, and segesterone.