Hello, whitening needle is usually 10- 12 needles as a course of treatment. Of course, everyone is different, and there are individual differences. It usually takes half a course of treatment for whitening needle to take effect, and the effect can only last 1-2 years. Supplementing vitamin C in the body can effectively improve skin color and avoid prolonged sunlight exposure. The whitening needle contains glutathione, which helps the body to detoxify and also helps cells to resist oxidation. Vitamin C whitening component of whitening needle has antioxidant effect and can reduce melanin.