What we know from the limited scientific studies that have been done is that cupping works by expanding the capillaries and increasing the amount of fluid that enters and leaves the tissues. Although there is plenty of anecdotal evidence that cupping can be effective and safe, very few clinical studies with humans have so far been conducted, making it difficult to “prove” many of the age-old benefits of cupping therapy. With that said, it has worked for millions of people for thousands of years.