How Does Capsaicin Work?AH sensations from the skin are relayed to the brain. One of the chemicals used by nerve cells that carry the sensation of pain is a small protein called substance P.Capsaicin causes these nerve cells to release substance P. This release is what produces the characteristic hot, burning sensation you feel when you eat hot peppers. However, when capsaicin is applied continuously for a while, substance P is depleted, and the nerves can’t pass along pain signals as efficiently as before. (Actually, this is a somewhat simplified version of a more complicated process.) Other sensory nerves are unaffected, so you will not experience numbing of the area to which the capsaicin is applied. What you will experience is some welcome relief.You may be asking yourself how applying capsaicin to the skin will help when the pain is coming from the joints beneath the skin. The answer lies in the fact that these nerve cells are branched, with some of the branches supplying the skin and others supplying the structures beneath the skin. Substance P is apparently depleted from all of the branches at the same time, providing relief from the pain of the arthritic joint.
DosageCapsaicin-containing creams are widely available in pharmacies. The creams used in the scientific literature contained either 0.025% or 0.075% capsaicin. A recent review article suggests using the higher dosage cream.When you start out, use only a little cream, as it will produce a burning sensation. After several applications, the burning will begin to diminish. This means that substance P is starting to be depleted. You can then increase the amount of cream you use. When you no longer feel the burning, you then know that you have reached the right dose. (The same method works with hot sauces. If you build up gradually, you will soon be able to painlessly down enough hot peppers to amaze and thrill your friends!)
Safety IssuesCapsaicin creams appear to be safe. The only reported side effect is the initial uncomfortable burning sensation, which stops after a few moments. In the studies, a few people quit using the medication because of this. However, remember that this effect will subside. Of course, you will want to avoid getting capsaicin into your eyes or onto other sensitive tissues. The pain can be quite excruciating, although no real harm should result. Take care to wash your hands after each application, or wear a glove while applying it. If you should need to apply capsaicin to your hands, one manufacturer’s recommendation is to apply it for 30 minutes, then wash it off after it has had time to have its effect. Otherwise, you may very well end up rubbing it into your eyes.*63/306/5*