I have been offering cupping therapy for over 10 years and teaching it for about 6 years. In my own clinical experience, it has been a very effective therapy It especially shines with releasing tight muscles. I have often been able to release knots and tension when people have tried every other therapy out there with no success.
Proper training for the cupping therapist is essential. Cupping can be a very good deep tissue therapy in the right hands, but a quick search online will bring up horror stories and nasty photos. Cupping can be a bit of an intense therapy, but it should never be painful. With modern equipment, cupping massage can be very relaxing and gentle.
The following article is a great place for therapists to learn more about cupping therapy! Mending the Fascia with Modern Cupping