Capsaicin for Fibromyalgia and Chronic Fatigue Syndrome

Capsaicin is derived from spicy peppers and is what gives peppers their heat. As a topical medication, it's used for a wide variety of medicinal purposes, including pain.

It might sound strange that the hot stuff in peppers can relieve pain, especially if you're not a fan of eating spicy food. Why would something that causes burning on contact with your tongue help alleviate pain? It sounds contradictory.

However, it's precisely that immediate burning sensation that's behind capsaicin's effectiveness. This drug is classified as a counter-irritant, which means that it causes pain in order to defeat it.

Here's one theory of how that works: everyone's cells contain something called substance P. It's a neurochemical that transmits pain signals to your brain. Capsaicin forces the cells in the tissue it touches to release all of their substance P, and that's the burning pain you feel. Once the substance P is gone, those cells can no longer send pain messages. Capsaicin takes away their postage stamps. Or, so I don't sound like an old fogey, it crashes their wi-fi.

Another possibility is that it actually desensitizes the peripheral nerves, which tend to be hypersensitive in us.

A fair amount of research has been done on capsaicin for a variety of conditions. Some research supports the topical use for:

• Neuropathy and other nerve pains
• Rheumatoid arthritis pain
• Osteoarthritis and other joint pains
• Back pain
• Muscle pain
• Post-surgical pain
• Cluster headaches (when taken as a nasal spray)

Capsaicin also has some non-pain-related uses, including:

• Psoriasis (a skin condition)
• Mouth sores stemming from radiation or chemotherapy

So far, we have no research specifically on capsaicin for chronic fatigue syndrome. However, because this disease can have some of the same pain types as fibromyalgia, the following studies may be relevant.

We have a small body of research on topical capsaicin for fibromyalgia pain. A 2010 review of evidence for complementary and alternative treatments (De Silva) found one study providing moderate evidence that capsaicin reduced tenderness but didn't improve other symptoms.

In a 2013 study of severe cases of fibromyalgia (Casanueva), researchers reported significant short-term changes in:

• Pain
• Depression (possibly as a result of lower pain levels)
• Role limitations due to emotional problems
• Fatigue severity
• Pressure pain threshold
• Measures of overall well-being and illness impact

However, this study only involved 70 people in the treatment group. Those people continued with their regular medical treatment and added capsaicin. The 60 people in the control group also continued their regular treatments but were not given a placebo. We need larger, placebo-controlled trials to replicate these results before we can put a lot of faith in the results.

A 2001 study on chronic, non-specific low back pain (Keitel) provides some evidence that capsaicin cream can help people with this type of low back pain who also have fibromyalgia.

Some research has been done on types of pain rather than on specific conditions. Some of these pain types are involved in fibromyalgia and may be part of chronic fatigue syndrome as well.

At least a portion of the pain involved in these conditions is believed to be from overactive nociceptors — specialized nerve endings in your skin that gather information about pain, temperature, and other environmental factors.

A 2015 study in Molecular Pain suggests that a single dose of topical capsaicin may alleviate nociceptive hypersensitivity. It also it also helped in pain inhibition, which is when your brain prepares for or adjusts to painful stimuli. Pain inhibition is believed to be dysregulated in fibromyalgia.

Fibromyalgia is also believed to involve a type of pain called neuropathy, which results from damaged or dysfunctional nerves. While we don't have evidence of neuropathy in chronic fatigue syndrome, at least one study (Anderson) suggest that chronic fatigue syndrome may share underlying biology, and therefore a significant overlap with, conditions involving neuropathy.

Multiple studies show that capsaicin may be effective against neuropathy, generally in combination with other medications. Possibly making these studies more relevant is a 2015 study in the European Journal of Pain showing that capsaicin is more effective in people with hyperalgesia, which is pain amplification by the nervous system. Hyperalgesia is believed to be a factor in both fibromyalgia and chronic fatigue syndrome.

Some benefits of capsaicin include:

• It's relatively inexpensive
• It's available over the counter at most grocery and drug stores
• It won't interact negatively with your other medications

As with all treatments, you'll need to weigh the risks and benefits to determine whether capsaicin is right for you. Talk to your doctor or pharmacist about any questions or concerns.

When you use topical capsaicin, it's important to remember that it works because it burns. However, while the burning sensation is normal, not everyone can tolerate it. Also, some people may experience side effects.

Capsaicin is available as a cream or in liquid form. The liquid is generally in an applicator that's similar to a roll-on deodorant or bingo dauber. Make sure you read and follow direction on the package.

When handling capsaicin, be sure to:

• Wear gloves
• Don't expose the skin to heat, such as from a heating pad or when your skin is heated up from a shower or bath
• Keep away from eyes and flush eyes with water if it gets in them
• Don't use it on broken or irritated skin
• Avoid sensitive areas and wash them with soap and water if they're exposed

Common capsaicin side effects include:

• Redness of the skin
• If dried residue is inhaled, coughing, sneezing, watery eyes, and sore throat can occur

Higher doses can result in additional side effects. Stop use and notify your doctor if you experience:

• Increased pain (beyond the initial burning sensation)
• Blistering
• Inflammation of the skin

It's also possible to be allergic to capsaicin. Avoid this medication if you're allergic to peppers. Get immediate medical attention if you have symptoms of a serious allergic reaction, which include:

• Rash
• Itching
• Swelling of the face, tongue, or throat
• Trouble breathing
• Severe dizziness

Don't use capsaicin if you're pregnant, trying to become pregnant, or breastfeeding.