SERMs form an oestrogen-like class of drug which is able to bind to oestrogen receptors of one organ system while remaining neutral to others. The SERM used in South Africa to prevent osteoporosis is raloxifene.
There are some negative effects though. There is an increased risk to develop thromboembolism (blood clots) and the drug is contraindicated in women who presently suffer from thrombosis, or have a past history of blood clot formation in their veins. Other side-effects are cramps and leg swelling.