Known by the popular brand Centchroman, these non-hormonal pills are effective contraceptive options without the side effects of hormonal contraceptives. Though these pills do not contain hormones, they act on hormones like progesterone produced by the body. Non-hormonal pills are easily reversible and are usually recommended to be taken once a week. Non-hormonal pills like Centchroman are 98-99% effective in preventing a pregnancy.