[AbiDrew85]

SP stands for saw palmetto, which is an herb that blocks the reduction of testosterone to the supposed-to-be-male-only form known as dihydrotestosterone. It also has slightly milder effects on blocking testosterone receptors and blocking the production of androgens from further up the synthesis pathway. It also contains a VERY mild and minute dose of a phytoestrogenic chemical.

Generally, it is used as a relatively safe anti-androgen by people who don't want to subject themselves to any of the much harsher stuff out there.