Cupping works by creating suction on the skin’s surface, which pulls skin and underlying tissue upward into a cup, expanding tiny blood vessels and triggering a cascade of local changes in blood flow, inflammation, and pain signaling. The negative pressure created inside the cup is the driving force behind every variation of the therapy, whether it involves glass cups heated with flame or plastic cups attached to a hand pump. What happens beneath the skin during those 5 to 15 minutes is more complex than it might look.
What Suction Does to Your Tissue
When a cup is placed on the skin and the air inside is removed, the resulting vacuum pulls your skin and the layers beneath it upward. This mechanical stretching separates layers of connective tissue (fascia) that surround your muscles, creating a lifting effect that can release tension in areas where tissue has become restricted or adhered. The suction also expands and ruptures tiny capillaries just under the skin, which is what produces the characteristic circular marks left behind.
That controlled micro-damage kicks off a repair response. Your body sends fresh blood to the cupped area to replace the damaged capillaries, essentially replenishing the tissue with healthier circulation. The vacuum also changes local fluid dynamics: it increases pressure in the space between cells, which stimulates your lymphatic system to ramp up its uptake of accumulated fluids and metabolic waste products from the treated area. Think of it as a localized flush, pulling stagnant fluid out and drawing fresh blood in.
There’s also a chemical component. The suction appears to stimulate production of nitric oxide, a molecule your body uses to widen blood vessels. More nitric oxide means greater vasodilation, which increases blood flow and volume to the area well beyond what the mechanical suction alone achieves. The negative pressure inside the cup also increases shear stress along the walls of blood vessels, which triggers the release of anti-inflammatory signaling molecules. These signals can dial down compounds linked to inflammation and tissue damage while boosting protective, anti-inflammatory ones.
How Cupping Reduces Pain
The pain-relieving effects of cupping likely involve at least two neurological mechanisms. The first is the gate control theory of pain. Your nervous system transmits pain signals through small-diameter nerve fibers, but it also has large-diameter fibers that respond to pressure, touch, and vibration. When those large fibers are activated, they stimulate inhibitory cells in the spinal cord that partially close the “gate” through which pain signals travel to the brain. The sustained pressure of a cup on the skin activates these large fibers, effectively turning down the volume on pain signals coming from the same area.
The second mechanism is called conditioned pain modulation, sometimes described as “pain inhibits pain.” When two painful stimuli occur simultaneously, your spinal cord activates a descending pathway that suppresses the original, primary pain. The mild discomfort of cupping can act as that competing stimulus, dampening chronic or exercise-related pain in the tissue beneath.
A meta-analysis of 10 randomized controlled trials found that cupping produced a statistically significant reduction in pain intensity for people with chronic musculoskeletal pain. The effect on pain was clear, though the same analysis found cupping did not significantly improve functional disability or mental health outcomes. In other words, it helps with how much something hurts more than it helps with how well you can move or how you feel overall.
Types of Cupping
All cupping relies on the same basic principle of negative pressure, but the technique varies in ways that matter.
- Dry cupping is the most common form. A provider heats the inside of a glass cup (traditionally by briefly igniting an alcohol-soaked cotton ball) to drive out oxygen and create a vacuum, then places it on the skin. Modern versions skip the fire and use a hand pump or suction device attached to plastic cups. The cups stay in place for several minutes.
- Wet cupping adds a step: before or after applying suction, the provider uses a needle or blade to make small, superficial punctures in the skin. When the cup is placed over these punctures, it draws out a small amount of blood. The meta-analysis data showed a trend toward wet cupping being slightly more effective for chronic pain relief than dry cupping, though the difference wasn’t statistically significant.
- Running cupping (or sliding cupping) starts the same way as dry cupping, but oil or lotion is applied to the skin first. Once suction is established, the provider glides the cups across the skin rather than leaving them stationary, covering a broader area.
Cups themselves come in glass, plastic, silicone, bamboo, ceramic, or metal. Silicone cups are squeezed to create suction rather than relying on heat or a pump, which makes them popular for home use and for therapists who want to combine cupping with movement.
Cupping for Athletic Recovery
Cupping gained mainstream visibility when Olympic swimmers appeared with circular marks on their shoulders in 2016, and it remains widely used in sports medicine. The primary application is reducing delayed onset muscle soreness, the deep ache that sets in 6 to 12 hours after intense exercise, peaks between 24 and 72 hours, and can linger up to a week in severe cases.
A 2025 study tested cupping at different suction pressures on young men immediately after a high-intensity leg workout. The results were striking and dose-dependent: higher suction pressures produced greater pain relief. At the strongest pressure tested, participants rated their soreness at roughly 1.6 on a 10-point scale compared to 6.1 in the control group. Those in the cupping groups also recovered faster functionally, shaving about 0.27 seconds off a 30-meter sprint and gaining 5 to 6 degrees of knee range of motion compared to untreated participants. Blood markers of muscle damage and inflammation both normalized in the higher-pressure groups.
The mechanism behind this likely involves increased blood flow speeding up the clearance of hydrogen ions and other metabolic byproducts that accumulate in muscle tissue during hard exercise. This clearance isn’t instant. The same researchers noted a significant delayed effect on fatigue reduction rather than an immediate one, suggesting the improved circulation needs time to do its work.
What the Marks Mean and How Long They Last
The circular discolorations left by cupping are not bruises in the traditional sense. A bruise forms from blunt impact that crushes tissue, while cupping marks result from blood being drawn to the surface by suction, expanding and sometimes rupturing capillaries from the inside out. The marks are technically a form of ecchymosis (blood pooling under the skin), but the mechanism is decompressive rather than compressive.
How long they last depends on their color, which reflects how much stagnation or congestion was present in the tissue. Light pink or red marks from a mild session often fade within a few hours. Deeper red marks typically clear in two to three days. Dark red marks with visible spots can take three days to a week. The deepest purple or dark red marks, which indicate significant blood stagnation, may take up to two weeks to fully disappear. The marks are painless for most people once the cups are removed, and they tend to be lighter with each subsequent session as local circulation improves.
Risks and Limitations
Cupping is generally low-risk when performed by a trained practitioner, but it isn’t without side effects. Burns can occur with fire cupping if the heated cup is applied carelessly. Wet cupping carries a small risk of skin infection at the puncture sites if sterile technique isn’t followed. Some people experience mild discomfort during treatment, particularly at higher suction levels, and the skin can feel tender for a day or two afterward.
The biggest limitation is that, while cupping reliably reduces pain perception, the evidence for broader benefits is less convincing. It doesn’t appear to significantly improve how well you function day to day or address the psychological dimensions of chronic pain. The high variability across studies (reflected in the wide statistical inconsistency seen in meta-analyses) also means that individual responses to cupping differ considerably. Some people experience dramatic relief, others notice little change. Treating it as one tool in a broader recovery or pain management strategy, rather than a standalone fix, aligns best with what the current evidence supports.