In general, the stovepipe needle can play a better stovepipe effect after the first injection, and the stovepipe effect can last longer. However, it should be noted that the effect of stovepipe needle injection is different, because everyone's physique is different. If the stovepipe effect is good after one injection, you can inject it again at a long interval. If the stovepipe effect is not good after 1 injection, multiple injections are needed. Generally speaking, the side effects can be effectively avoided by controlling the dose and concentration of leg-stovepipe needles, but how to use leg-stovepipe needles excessively or inject leg-stovepipe needles too frequently will easily cause side effects to human body. When injecting stovepipe needle, you must not inject it many times and frequently in a short time in order to pursue the effect.