Vein reduction with sclerotherapy is a safe, effective, minimally invasive procedure that can greatly diminish the appearance of spider veins on the lower extremities. A sclerosing agent is injected into the spider veins with a very fine needle. Over a period of weeks, the vessels turn into scar tissue that fades, leaving you with noticeably clearer, more attractive legs. You may require more than one treatment to achieve your desired outcome.