Paraffin wax may be used to help relieve pain in the hands of people with osteoarthritis, rheumatoid arthritis, fibromyalgia, and other joint mobility issues. It acts like a form of heat therapy and can help increase blood flow, relax muscles, and decrease joint stiffness. Paraffin wax can also minimize muscle spasms and inflammation as well as treat sprains.

Paraffin wax is a common option in heat therapy treatments for people with arthritis or other rheumatic diseases -- the heat helps increase blood flow and relax the muscles, which can help relieve caused by arthritis, osteoarthritis and fibromyalgia [sources: National Institute of Arthritis and Musculoskeletal and Skin Diseases].

Paraffin wax can even soften hardened skin caused by scleroderma, a disease in which collagen accumulates on the body -- it increases the skin's elasticity, allowing for increased movement and mobility, especially on the skin covering the hands.

But the benefits of paraffin wax don't stop there. Because paraffin wax treatments are a form of heat therapy, they're often used for muscle, tendon and ligament ailments. As with conditions like arthritis, they increase blood flow, improve joint stiffness and reduce pain. They're also used to treat bursitis, tendonitis, sprains and pulled muscles.

Source: How Stuff Works for the Full Article.