Sclerotherapy is the treatment for Spider Veins by injecting a sclerosing agent directly into the spider veins.  This causes irritation to the walls of the vessel resulting in a sclerosed or non functioning vein.  During the healing process, blood stops flowing through the vein and thus the vein is less apparent.  This typically requires multiple treatments of the same vein(s).  There are many different sclerosing agents used however, at Anti Aging & Functional Medicine, we use Glycerin, which is less painful and with fewer side effects.