Informative article below. For some time we've known FMS is due to problems with pain perception (also some other problems such as inability to sleep well - melantonin production backwards, etc). The following is an interesting article for those interested in how our pain is "sensed" by those of us with FMS: From: http://www.medscape.com/viewarticle/409781 Question: What is Substance P? What is Substance P? Where is Substance P found in the body? How is Substance P related to arthritis and arthritis pain? Answer: How Substance P is Related to Pain Nerve cells communicate with one another through neurotransmitters. Substance P is one such neurotransmitter. It is a protein found in the brain and spinal cord, and is associated with some inflammatory processes in the joints. Its function is to cause pain. Substance P has been implicated in pain syndromes such as: low back pain fibromyalgia arthritis Newer research has looked at a more intricate and expanded role for Substance P. Evidence about the role of Substance P has evolved since it was first discovered around 1931. Substance P is now believed to be involved in the integration of pain, stress, and anxiety. Substance P also is involved in other physiologic activities such as: the vomiting reflex defensive behavior change in cardiovascular tone stimulation of salivary secretion smooth muscle contraction vasodilation Substance P: A New Era, a New Role, from Medscape (log-in required) Decreasing the Effect of Substance P on Pain New research about Substance P may lead to new drugs and treatments. As it is now, over-the-counter creams comprised of capsaicin (made from chili peppers) are felt to help deplete substance P from local nerve endings and relieve pain. According to rheumatologist, Scott J. Zashin, M.D., "It may take 1 to 4 weeks to work. The capsaicin cream will often burn or sting, which will typically resolve during the first week of treatment but may last longer. Once pain relief has occurred, treatment must continue to maintain benefit until the problem no longer persists." Contact with eyes may be irritating so always wash your hands if capsaicin cream touches them. If you are applying the capsaicin medication due to hand pain, leave it on for 30 minutes before washing. Sources: Scott J. Zashin, M.D., clinical assistant professor at University of Texas Southwestern Medical School, Division of Rheumatology, in Dallas. Substance P: A New Era, a New Role, Pharmacotherapy, C. Lindsay DeVane, Pharm.D., http://www.medscape.com/viewarticle/409781.