Acupuncture is a form of alternative medicine and a key component of traditional Chinese medicine in which thin needles are inserted into the body. Acupuncture is a pseudoscience because the theories and practices of TCM are not based on scientific knowledge, and it has been characterized as quackery. There is no scientific proof that the meridians or acupuncture points exist, and it is hard to prove that they either do or do not, but numerous studies suggest that acupuncture works for some conditions. Some experts have used neuroscience to explain acupuncture.