In traditional Chinese glass cupping, the glass cup is placed on the patient’s skin after the cup is quickly heated with fire for one to two seconds. As the therapy cup cools, it creates a weak partial vacuum with maximum negative pressure of -150 mm Hg.
Over 30 years, my father and I designed more than 40 different shapes and sizes of glass fire cups, ranging from 1 to 15 cm in diameter to fit both flat and curved surfaces of the body. These customized glass cups can create -50 to -300 mmHg of negative pressure depending on the size of the cup.
Small and medium cups with concave open mouths are designed to treat uneven or curved surfaces of the body, including fingers, wrists, ankles, neck, head, and face. Larger cups are often necessary to generate enough negative pressure to treat larger and deeper stagnant areas of the body.
Larger cups also allow a greater amount of tissue uplifting inside the cup to affect blood stagnation of deeper tissues. For example, the wet cups I use for lower back pain have a volume of ~1000 cubic centimeters, which can produce approximately -300 mm Hg of negative pressure, cause up to 3 inches of tissue uplifting, and remove up to 500cc of stagnant blood per cup. The heat during the modified fire wet cupping further dilates skin pores and punctured sites enough to remove chronic inflammation and toxins.
The most unique feature of this modified glass fire cupping technique is the use of a wick made from a commercially available paper tower. The wick is made by taking an approximately 3-inch square relatively firm paper tower and rolling it into a long cylindrical 0.5 cm thick wick. The wick is dipped partially into an ethanol alcohol jar, which is then set on fire.
While holding the bottom end of the burning wick over the affected area of the body with one hand, an appropriate size and shape of the cup is placed directly over the burning wick with the opposite hand.
The holding hand is then removed quickly before the cup is tightly pressed down on the affected skin surface. This particular technique allows practitioners to create up to -300 mm Hg of negative pressure since the intensity of the application of cupping with these fire glass cups is equally dependent on the volume of the cup and the amount of heat produced by the burning wick during the procedure.
Since the negative pressure from cupping and the amount of tissue uplifting are perhaps the main factors inducing therapeutic effects, the intensity of negative pressure and the size of the cup are essential in the treatment of certain conditions such as low back pain, piriformis syndrome, tendinitis, and hemochromatosis, which require at least 250 mmHg of negative pressure and 10-15 cm diameter cups with at least 10 cm height to affect deeper tissue and organs and have positive outcomes.
Using an improper cup size or inadequate therapeutic negative pressure generated from both ancient and modern cups is precisely why, I believe, cupping therapy failed to address many treatable conditions and produced inconsistent results.
However, when proper size and intensity of cupping are applied to the selected site by experienced practitioners, cupping therapy is one of the most effective medical modalities to treat a myriad of medical conditions related to Eohyeol or blood stagnation.