- Most people’s experience of needles is that of those used to give injections, take blood etc. Acupuncture needles differ from these hypodermic syringes in that they are much finer and are solid rather than hollow, they are designed to part the skin without cutting the tissues. Sterile stainless steel needles are commonly used with a diameter of between 0.25mm to 0.45mm which is about the thickness of a human hair.