Gua sha is not bad for most people when done correctly. The technique deliberately causes tiny capillaries under the skin to burst, creating red or purple marks called petechiae, which can look alarming but typically heal within a few days to a week. The real risks come from using too much pressure, scraping over the wrong areas, or having certain medical conditions that make the practice unsafe.
What Those Red Marks Actually Are
The colored marks gua sha leaves behind are its most misunderstood feature. When a smooth-edged tool is pressed and stroked across skin, tiny blood vessels near the surface burst. This produces the distinctive red or purple spots known as “sha.” These aren’t injuries in the way a bruise from bumping into a table is. They’re an intentional result of the technique, and they signal increased blood flow to the area.
A pilot study measuring skin circulation found that gua sha caused a fourfold increase in blood flow to the treated area in the first seven and a half minutes after treatment, with significantly elevated circulation lasting at least 25 minutes. That boost in local blood flow is thought to play a role in reducing muscle pain, though researchers noted there’s also an unidentified pain-relieving mechanism at work beyond just improved circulation.
The marks can be tender while they’re healing, but they should fade within a few days. If bruising is severe or lasts longer than a week, you’re likely using too much pressure.
When Gua Sha Can Cause Problems
The most common way gua sha goes wrong is simple: pressing too hard. On the face especially, where skin and tissue are thinner than the rest of the body, excessive pressure can burst capillary beds and leave lasting bruises rather than light redness. Scraping back and forth or in random directions instead of smooth, consistent strokes can also stretch and irritate skin.
Active acne and open wounds are another concern. Dragging a tool over breakouts pushes bacteria and debris deeper into pores, which can trigger flare-ups, redness, and broken capillaries. For people with cystic acne, this can also damage the skin barrier and increase the risk of scarring or dark spots that linger after inflammation fades.
Dirty tools create their own problems. Stone and jade gua sha tools harbor bacteria and dirt the same way makeup brushes do. Without regular cleaning, you’re essentially dragging accumulated grime across your face. Washing your tool with antibacterial soap for at least 20 seconds after each use, then drying it with a clean towel, prevents this. A quick spray or dunk in rubbing alcohol adds extra protection. Metal tools can be sterilized in boiling water, but stone and resin versions will crack under that heat.
Medical Conditions That Make It Unsafe
Because gua sha intentionally breaks capillaries, certain health conditions turn a minor cosmetic side effect into a real medical risk. You should avoid gua sha if you:
- Take blood thinners. Medications for blood clots make it harder for your body to stop bleeding, even under the skin. What would normally produce light petechiae could cause significant bruising or hematomas.
- Have diabetes. Diabetes can affect skin healing and circulation, making the intentional micro-trauma of gua sha slower to recover from and more prone to complications.
- Have circulation problems. Poor blood flow changes how your body responds to the pressure and how quickly tissue recovers.
- Are pregnant or may be pregnant.
For facial gua sha specifically, skip it if you’ve had cosmetic injections (like fillers or botulinum toxin) within the past month. The pressure and movement can shift product placement. People with ongoing inflammatory skin conditions like psoriasis or rosacea should also avoid it, since the scraping motion aggravates already-sensitized skin.
What Gua Sha Does to Your Immune System
Beyond surface-level effects, gua sha triggers a measurable immune response. Research has shown that the technique raises levels of several pro-inflammatory signaling molecules in both the treated skin and the bloodstream. At the same time, it lowers levels of immune-suppressing signals. The net effect is a temporary upregulation of immune activity, both locally and throughout the body.
This sounds concerning if you associate “inflammation” with something harmful, but short-term, controlled inflammation is how your body heals and defends itself. It’s the same principle behind exercise-induced muscle soreness or the redness around a healing cut. The research found no significant change in anti-inflammatory markers, suggesting the body’s overall balance isn’t thrown off. For most healthy people, this temporary immune activation isn’t a problem. But for anyone with an autoimmune condition or chronic inflammatory disease, it’s worth discussing with a provider before adding gua sha to a routine.
How to Minimize Risk at Home
Facial gua sha should feel like gentle pressure, not scraping. A good rule: if light redness appears, you’re in the right range. If it hurts, you’ve gone too far. Hold the tool at a low angle against your skin rather than pressing the edge straight down, and always move in one direction with smooth, consistent strokes. Don’t go back and forth over the same spot.
Avoid any area that’s swollen, broken out, sunburned, or irritated. Apply a facial oil or serum first so the tool glides rather than drags. Clean your tool after every single use.
Body gua sha, the traditional form used on the back, neck, and limbs for muscle pain, involves more pressure than facial gua sha and produces more dramatic marks. This version carries a higher chance of discomfort and bruising, and is better suited to a trained practitioner who can gauge appropriate pressure for different muscle groups and adjust based on what they find. The fourfold circulation increase measured in studies came from this type of treatment, and while the benefits can be significant for muscle tightness and pain, so can the bruising if technique is poor.
For most people, gua sha is a low-risk practice with a straightforward safety profile. The marks look worse than they are, the side effects are predictable, and the situations where it becomes genuinely dangerous are specific and avoidable.