Can massage guns be harmful?

When used correctly, they are very safe. Avoid using them on bones, joints, nerves (neck front, armpit, groin), acute injuries, or inflamed areas. Do not apply excessive pressure let the gun do the work. Limit use to 2 minutes per muscle group and 15 minutes total per session. People on blood thinners, with nerve disorders, or with deep vein thrombosis should consult a doctor before use.