How many different sclerotherapy treatments are needed to heal spider veins?

Multiple treatments: Spider veins are treated by sclerotherapy and you must remember that sclerotherapy is a process. In my practice most patients require about 3 cycles of treatments with one treatment given every 6 weeks. Some may require more and some less. If patients have many spider veins then i recommend a venous reflux exam before starting sclera to look for malfunctioning valves. See a vein specialist.

Varies: In most cases just one. Sometimes it may take a second treatment.

Depends: Difficult question to answer without examining your legs. I would advise that you meet with a vein specialist to examine your legs to determine that. Some people may only need 1 session while others with extensive veins may needle multiple session done on each leg. The larger the veins (all spider veins not created equal), the darker, & the more numerous the veins are the more therapy is needed.