Yes, the 13.0mm body cartridge may be used on the inner thigh if there is enough fatty tissue in the treatment area. However, because 13mm is a deep-treatment cartridge, avoid the groin, genital area, major blood vessels, knee/joints, and bony areas. If the inner thigh area is relatively thin, a 6.0mm or 9.0mm cartridge may be more appropriate. Always start with a low energy level and stop if you feel sharp pain or excessive discomfort.