A hot and spicy pain remedy that’s worth a try
The Irish Times
Health Supplement, p. 13
17 February 2009
DOES IT WORK? Capsaicin for pain relief
HOT CHILLI peppers are well known for adding spicy heat to dishes, or in the making of cayenne pepper and paprika.
The same peppers have a long history in herbal medicine. Their use in food is thought to have originated to relieve stomach aches, intestinal cramps and gas. As a herbal remedy, they have been used in creams applied to the skin for pain relief. This topical preparation is known by various names, especially capsicum (derived from the peppers’ Latin name) or capsaicin (the active ingredient found in the peppers). Creams containing capsaicin are available on prescription in Ireland.
Capsaicin creams lead to a similar reaction on the skin as hot peppers have in the mouth. The skin feels like it is burning and stinging, which can be very painful. After a number of uses, the area becomes desensitised, giving the person an overall sense of pain relief.
Capsaicin was also in the news last year when its use on Denis Lynch’s horse in the Olympic show-jumping led to his dismissal for using a banned substance.
Although Lynch insists he used it only in warming up his horse, capsaicin is banned because it can be used to make horse’s legs hypersensitive which is believed to help them jump better in competition.
Evidence from studies
Laboratory studies have revealed that when capsaicin is applied to the skin, it stimulates nerve endings to release something called “substance P”. At first this causes pain, but repeated applications use up all the stored substance P so that the person no longer feels the pain. This can sometimes lead to long-term relief of the pain.
Several randomised controlled trials have been conducted with capsaicin. However, these studies are challenging because people usually know they are receiving a placebo as these creams will not feel hot. However, the capsaicin creams consistently give greater pain relief than placebos. Most studies have been conducted with muscle and joint pain. However, capsaicin was not as effective in relieving this sort of pain as ibuprofen gels.
A small number of studies have also found capsaicin effective with what is called neuropathic pain. This form of chronic pain often has no clear cause. It can develop along with diabetes, shingles or other diseases or can linger long after an injury has healed.
The pain varies, but usually has a burning, shooting or tingling sensation. The pain is thought to arise from damage to nerve fibres, but it is poorly understood and standard treatments are not very effective. Capsaicin has been found to help some people with neuropathic pain, especially when other treatments have not worked.
Although capsaicin gives the sensation of burning, it does not lead to blisters, redness or any of the other damage of an actual burn. However, quite a few people find the pain and burning of the initial applications too severe to tolerate. Great care should be taken to avoid getting the cream into eyes as the pain can be excruciating.
After the cream is discontinued, some people experience numbness for several days where it was applied. Although this can be worrying, feeling should return gradually.
Capsaicin is very potent, so creams are usually made in concentrations of 0.025 to 0.075 per cent.
Recommendations state that it should be applied three or four times daily. Using it less frequently has been reported to cause additional pain.
Capsaicin is a pain-relieving cream which works via a completely different mechanism from other common pain relievers.
For this reason, it may be particularly beneficial for those who are not getting relief from standard pain treatments. However, it also does not work for every form of pain. One review found that about one in six people with neuropathic pain had a 50 per cent reduction in their pain after using capsaicin.
For those with muscle or joint pain, about one in eight had a similar reduction in their pain. For those who can tolerate the initial painful sensations, capsaicin may be worth trying.
However, there is no evidence that it cures any of the underlying causes of the original pain.