For years, despite the clear therapeutic effects of acupuncture in treating many diseases, there were few convincing studies that explained how acupoint stimulation worked, or what meridians were anatomically speaking, so the technique always seemed somewhat mysterious.

However, as scientific research of acupuncture has grown in recent years, producing better quality results, the technique is gaining traction around the world.

One debate revolves around the foundation of acupuncture — the question of whether meridians actually exist.

Yang Shengya, director of the Department of Acupuncture and Moxibustion at the Beijing Massage Hospital, explains that meridians are more of a functional concept than a concrete anatomic structure.

"The qi and blood only run in meridians in a living person. When a person dies, there is no qi and blood does not circulate anymore, so comparing meridians to vessels or nerves is not accurate," Yang says.

"From the perspective of clinical practice, meridians describe the function of pathways through the human body. Once a person dies, the function ends immediately.

"Maybe in the future, we will be able to explain what meridians are exactly. But, just because you cannot see something, that doesn't mean it doesn't exist."

Liu echoes Yang's opinion, saying that studies of the anatomic structure of meridians lead nowhere, so now many researchers are trying to explain the mechanisms of acupuncture, instead — such as why pricking the acupoints on the face can relieve toothache.