Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientific knowledge, and it has been characterized as quackery.

There is a range of acupuncture technological variants which originated in different philosophies, and techniques vary depending on the country in which it is performed. However, it can be divided into two main foundational philosophical applications and approaches; the first form being the modern standardized form called eight principles TCM and the second an older system that is based on the ancient Daoist wuxing, better known as the five elements or phases in the West. Acupuncture is most often used to attempt pain relief, though acupuncturists say that it can also be used for a wide range of other conditions. Acupuncture is generally used only in combination with other forms of treatment.

The global acupuncture market was worth US$24.55 billion in 2017. The market was led by Europe with a 32.7% share, followed by Asia-Pacific with a 29.4% share and the Americas with a 25.3% share. It was estimated in 2021 that the industry would reach a market size of $55bn by 2023.

The conclusions of trials and systematic reviews of acupuncture generally provide no good evidence of benefit, which suggests that it is not an effective method of healthcare. Acupuncture is generally safe when done by appropriately trained practitioners using clean needle technique and single-use needles. When properly delivered, it has a low rate of mostly minor adverse effects. When accidents and infections do occur, they are associated with neglect on the part of the practitioner, particularly in the application of sterile techniques. A review conducted in 2013 stated that reports of infection transmission increased significantly in the preceding decade. The most frequently reported adverse events were pneumothorax and infections. Since serious adverse events continue to be reported, it is recommended that acupuncturists be trained sufficiently to reduce the risk.

Scientific investigation has not found any histological or physiological evidence for traditional Chinese concepts such as qi, meridians, and acupuncture points, and many modern practitioners no longer support the existence of life force energy (qi) or meridians, which was a major part of early belief systems. Acupuncture is believed to have originated around 100 BC in China, around the time The Inner Classic of Huang Di (Huangdi Neijing) was published, though some experts suggest it could have been practiced earlier. Over time, conflicting claims and belief systems emerged about the effect of lunar, celestial and earthly cycles, yin and yang energies, and a body's "rhythm" on the effectiveness of treatment. Acupuncture fluctuated in popularity in China due to changes in the country's political leadership and the preferential use of rationalism or scientific medicine. Acupuncture spread first to Korea in the 6th century AD, then to Japan through medical missionaries, and then to Europe, beginning with France. In the 20th century, as it spread to the United States and Western countries, spiritual elements of acupuncture that conflicted with scientific knowledge were sometimes abandoned in favor of simply tapping needles into acupuncture points.

Reference: wikipedia