Cupping therapy, a traditional Chinese medicine technique used to treat chronic pain and speed muscle recovery, works by creating suction on the skin to increase blood flow. But what exactly does that suction pull out of the body? Researchers reporting in ACS’ Analytical Chemistry have developed a noninvasive way to find out, capturing and analyzing the compounds drawn into the cup itself.

“I have a longstanding interest in analyzing volatiles related to human metabolites, for example, in the breath. It is always best to capture these volatiles directly at the source — for example, have a patient blow into an analytical instrument or, as in the present study, collect directly in the cupping jars.”

Renato Zenobi, corresponding author

Capturing What the Skin Releases

Despite cupping’s widespread use, scientists have rarely studied its effects on human physiology, and previous studies examined metabolites in blood or urine rather than what is released directly from the skin’s surface. To close that gap, Zenobi, Xiaowen Yan, and colleagues identified a polymer-coated membrane that adsorbs and concentrates airborne molecules; captured compounds were then released by heating the membrane and identified using mass spectrometry.

The team first validated the approach using a vacuum-suctioned cup on pig skin treated with five compounds known to occur on human skin — all five were successfully captured and detected by the membrane. They then conducted a proof-of-concept study with 12 healthy human volunteers, placing cups fitted with the coated membranes on participants’ backs and waists for 10 minutes, matching typical treatment duration.

Comparing the air inside cups with and without vacuum suction — representing conditions during and before cupping — the researchers observed substantial differences in 13 metabolites and compounds commonly found on the skin surface, including aldehydes, ketones, alcohols, terpenes, and organic acids. Some of these compounds increased in concentration after cupping, while others decreased.

“The metabolic effects of TCM therapies can be studied with modern analytical techniques, which is something that has largely been lacking.”

Renato Zenobi

Zenobi cautions that the findings are preliminary: “Firm conclusions that are statistically significant should only be drawn when many more patients and controls have been analyzed.” The researchers next plan clinical studies with a local hospital focused on traditional Chinese medicine, comparing people with conditions such as chronic pain to those without, in hopes of better understanding cupping’s effects on the body.

The study was approved by the Ethics Committee of Xiamen University and funded by the National Natural Science Foundation of China, the National Key Research and Development Program of China, and the Fujian Provincial Natural Science Foundation of China.

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The study was published June 10, 2026, in Analytical Chemistry (DOI: 10.1021/acs.analchem.6c02559).