Chili peppers' surprising pain relief

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This post is brought to you by Columbia Pictures "Moneyball"

Human beings are supposed to avoid chili peppers. The fruit contains a fiery irritant, called capsaicin. It’s so strong that one milligram of the flavorless white crystalline stuff placed in your palm burns like a lighted cigarette, and the pain lasts for hours.

Chili peppers evolved this defense mechanism because their seeds die in the guts of mammals. Capsaicin is the plant’s way of saying “back off.” (Chili pepper seeds can survive being eaten by birds, which don’t have receptors to feel capsaicin. In fact, chili plants “want” birds to eat them because birds are excellent chili propagation vectors.)

Unlike most mammals, human beings enjoy the burn of capsaicin in their food. And there’s another reason to like it besides its culinary thrill: in large doses, capsaicin causes long-term desensitization of neurons that send pain signals to the brain.

That point was made clear to me a few years ago when I paid a visit to Neurogesx in San Carlos, California. Annika Malmberg, the director of pharmacological research showed me a transdermal pain relief patch containing capsaicin. It was coated with a clear gummy gel. When I reached out for it, she said, “Oh no! Don’t touch,” pulling it away and sticking it on the back of her own hand.

“But you’re touching it,” I said. “Ahh,” she said, dismissively waving her other hand. “I’m completely desensitized.” If I had put the patch on, however, my hand would start to hurt like hell, at least until my nerve cells shriveled up.

Neurogesx was founded by Dr. Wendye Robbins, based on her success in 1997 using capsaicin to treat patients with debilitating nerve pain when she was an assistant clinical professor of anesthesiology at the Mount Zion Pain Center in San Francisco. There, Robbins used a cream containing nearly 10% capsaicin (about 100 times the amount found in over-the-counter arthritic rubs) on HIV patients who had severe chronic foot pain and had been unable to find relief using any other drug, including morphine. Sixty percent of Robbin’s capsaicin patients reported that their pain had been reduced by at least 50 percent, and all the patients reported at least some pain relief. Now with $30 million in venture capital, Neurogesx has a transdermal patch on the market called Qutenza, which contains 8% capsaicin. A single, one-hour application can alleviate the debilitating pain that often follows a case of shingles.

Neurogesx is currently running clinical trials to study other uses for capsaicin. Who would have thought that this natural compound, evolved to keep people away from it, would be so alluring?


  1. Wow, this is freaking awesome. I can think right now of a few people who could benefit from this (myself included). No more ben gay smell!

  2. This post interests me; I’m allergic to opiates.  However…screw ‘Moneyball’ and Columbia Pictures.

  3. Columbus added “peppers” to chilis to promote the idea he had reached the Far East source of pepper. I think.

  4. I can testify to this. I’ve had a case of shingles for about three weeks now, and three things have kept me sane: Percocet, 12-hour lidocaine patches, and an OTC (much, much weaker) capsaicin rub. If, $DEITY help me, I develop post-herpetic neuralgia (a.k.a. after-shingles permanent agony syndrome), my GP has already said Qutenza will be one of the first things we’ll try. I’m all for it.

  5. If you want some light reading, check out the prescribing info for Qutenza (“Indications & Dosage” tab), especially the part about safely discarding even the after-treatment cleansing gel.

  6. Anecdote time: When I was in junior high, I strained my wrist during the gymnastics unit in gym class. It hurt and hurt and hurt and hurt for a couple of weeks with no sign of going away. My mom had some capsaicin cream for arthritis pain. She had me use it as directed, and whatever was going wrong with my wrist quickly went away. I thought that was the weirdest thing ever, since there was no convincing me that it wouldn’t just make my hand burn (which it did, a little, especially in the sun.)  I wouldn’t be surprised if it was because of the substance p-blocking action of capsaicin. 

    Just recently, my mom turned me onto some epsom salts cream for muscle aches. My jury’s out on that so far. However, I did notice that it contained capsicum in addition to magnesium sulfate and whatever other gunk makes it creamy, and enough to make you tingle quite thoroughly if you rub it in hard. I wonder if the epsom salt cream works because it’s really full of capsaicin (substance P blocker) and not full of epsom salt…

  7. A few years back when I was working for a chemistry magazine, I did a cartoon about some of the research that led to this product. I’m relieved to see that the chilli-based aid to pain relief is being manufactured in the form of a transdermal patch and not, as my cartoon predicted, a suppository.

    1. ouch, that’d really hurt. One time I was eating at a braziliian restaurant, and using a good deal of the hot sauce they had (basically tiny hot peppers in oil) and got some on my hands. I wiped it of with a napkin. LAter in the dinner, I went to the restroom. Since I’m a fella, I had to touch my junk before and after (for a little shake). The resulting pain was horrendous and lasted for about an hour. A burning hot nightmare!

      1. Many moons ago an uncle of mine, whilst canning hot chilis with my dear Auntie, visited the toilet and had a similar experience. 

        The pain was so intense he wound up using spackling compound to cool it off. To this day I cackle aloud if the thought/image comes to mind.

    1. I actually take capsaicin capsules for headaches. One capsule reliably helps the pain. So I’m not surprised eating hot chiles works for you!

      1. Cool. I’ve used the capsaicin nasal sprays for sinus headaches (hoooo doggies, one squirt of that stuff will clear out your head but good), but I didn’t know about the capsules. I’ll have to give those a try for both sinus and non-sinus headaches.

  8. “Who would have thought that this natural compound, evolved to keep people away from it, would be so alluring?”

    Actually, it’s not at all surprising that a plant would have evolved a really interesting and medically useful substance.  A significant number of effective drugs are STILL plant-derived, rather than designed in some laboratory.  Pharma companies have entire research divisions devoted to exploring (and patenting, sadly!) the chemicals which nature has already evolved via millions of years of arms races between predators and prey.

    Yet, we persist in cutting down the rain forests (largest source of biodiversity on the planet) for fancy new furniture and biofuel farmland for our cars.

    1. I think you’re missing the point.

      It’s not surprising that it is derived from nature (as is Morphine), but that it is derived from a substance that evolved to keep us away.

      It’s ironic.  Get it?

  9. I used Dave’s insanity sauce and tiny habenero slices (on a cracker with some cheese) to quit smoking – the endorphine rush replaced the desire for nicotine. When you want a smoke, reach for the chilis and make sure you get a deep-down-in-your-soul burn. (And keep a glass of milk or hunk of cheese handy).

    After trying and failing to quit for a number of years, I was smoke free in a matter of months.  Then, unfortunately, I became a huge chili-head for about a year… but I imagine that was probably a good thing overall.  I haven’t smoked, or desired to smoke, since.

    1. That is so great! I am sharing your idea with a few friends who may want to quit.

      And BIG-ASS KUDOS to you for quitting! It’s been about 3 years since I quit smoking tobacco. Whenever I crave one, I just puff something more medicinal.  ;)

    2. Also…given a choice between smoochin’ a smoker and sucking face with a cheese-and-chili muncher, I’ll take the Habenero Dragon breath every time, with a dash of insanity, please!

  10. Michael Pollan would remind us that chili peppers are still evolving: they’ve developed a symbiosis with these smart mammals who hybridize them and make their capsaicin stronger and stronger every year.

  11. Please be careful about how you use these. Capsaicin has been looked at in the clinic before, and a side effect in primates is elevated body temperature–it can get REALLY high if it gets into your bloodstream. Ironically, it works way better in other models (murine), as they have a feedback loop to cut off the escalating temperature that primates lack.

    1. Jeb, if you read the link I posted earlier, you’ll see that it can be used no more than once every three months and that it *must* be applied by a skilled medical practitioner. This is not Extra-Strength Tiger Balm that you can buy off the shelf at Walgreen’s.

  12. I grow habaneros, and have gotten to the point where I don’t worry about gloves or anything else while working with them. Pull one off the plant, slice it up, plop the slices into a little container I use to carry with me, no problem at all.

    I do, however, have to be real careful about not letting that stuff get on other people, so wash my hands at that point. Or every now and then will find a new point on my body (usually face) which hasn’t been desensitized yet, so there’s some burn… but it’s not unpleasant either.

  13. I don’t know.  I worked in a music store when they came out with an album and it caused me nothing but pain after the 4th straight day of blasting it on the speakers.

    1. aw man, that would be absolutely terrible, much worse I’d think than mixing it up with a penis wrap (whatever that is). 

  14. “Chili pepper seeds can survive being eaten by birds, which don’t have receptors to feel capsaicin.” This is also the basis of the accidental discovery of ‘squirrel resistant birdseed’.

  15. When I reached out for it, she said, “Oh no! Don’t touch,” pulling it away and sticking it on the back of her own hand.“But you’re touching it,” I said. “Ahh,” she said, dismissively waving her other hand. “I’m completely desensitized.” If I had put the patch on, however, my hand would start to hurt like hell, at least until my nerve cells shriveled up.

    Step 1: desensitize myself to capsaicin.
    Step 2: cover every surface in my dining room in capsaicin patches.
    Step 3: invite enemies to reconciliatory dinner party.
    Step 4: publish memoirs, “Revenge Is A Dish Best Served… Picante!

    1. Heh. Reminds me of a classic “historical” headline from The Onion: “Senator Huey Long Assassinated, Cajun Style: Dies ‘Real Spicy-Like,’ Say Witnesses.” Alas, the article itself is not available online; I think it’s only in Our Dumb Century.

  16. “Unlike most mammals, human beings enjoy the burn of capsaicin in their food”

    I’ve had both dogs and cats that like spicy food.

    I also know someone who used cayenne on birdseed. The squirrels came to like it as well.

    1. One of my cats seems completely unaffected by capsaicin. We sprinkled cayenne powder on our countertops to discourage the cats from jumping up. This cat jumped up on the countertop, stuck her nose directly into the cayenne, sniffed it thoroughly, and then walked nonchalantly through it. She’s also chewed on a fresh cayenne pepper, and showed no discernible reaction.

      The other cat gets red, runny eyes whenever we cook curry, just from the capsaicin in the air. On the other hand, she does nuzzle and lick my hands if I’ve been chopping chiles and have neglected to wash my hands. Maybe she’s affected, but gets an endorphin hit from it.

    2. My father was an outfitter up north and told me a story of a bush-pilot who had problems with bears chewing up the floats on his plane. He thought he’d try the Bear Spray, which is super hot pepper spray. We’ll long story short; bears loved the spray and tore up the floats even worse than before. (In another test, they sprayed an old tire and buried it on the beach. They watched from the float plane as a bear walked out of the woods, caught the smell, dug up the tie and played with it for over an hour.) 

      So I guess they like the heat and the taste too, just not sprayed in their face. Also, better to test on an old tire than your float plane.

  17. While I like this post, and while I have used products such as you describe with benefit, I do have an issue with some of the language used, language that suggests a point of view contrary to mainstream biology.  When you write “Chili peppers evolved this defense mechanism because their seeds die in the guts of mammals,” you, perhaps unconsciously, are lapsing into adaptionism.  While I see that often in writing, it is beneath a site such as this one that I admire for its respect and enthusiasm for science.  Organisms do not evolve traits in order to accomplish certain tasks, at least not according to mainstream biology.  (There are some adaptionists who are mainstream scientists, but the view is not that held by most biologists presently.)  Rather, having certain traits, traits arising out of genetic mutations, can confer a survival advantage for an organism, leading to a greater likelihood that its genes will be replicated through reproduction.  Such a trait might be such that decreases the likelihood that a plant will be consumed by such foragers whose digestive systems will destroy the seeds of that plant.  Of course, artificial selection also occurs, in which humans breed for species traits (e.g., creating pest-resistant soybeans), or otherwise engineer species changes according to human goals, but that is a different matter.

    1. I agree, Dawkins “The Selfish Gene” is a good accessible primer on this.  It’s important in scientific thinking to realize things like water and oils don’t actually dislike each other, it’s an interaction between and within their molecular structures that causes their immiscibility.  There is a very human tendency most of us have to personify these things, but it’s wrong to do so when you talk science. 

    2. I agree, in fact after you pointed out the (I’m guessing) lazy choice of words, it almost suggests to me Lamarckian Inheritance, which has been relegated to the “interesting idea, but not true” bin of science (insofar as it relates to biology).

  18. People’s mileage varies with this, have seen some blisters caused by other preps of hot peppers, so be careful.  Have not seen any with this type.  Be especially careful about touching eyes, tender regions after handling.  Harrison’s Internal Medicine, a text which which has traditionally been pretty stodgy about anything herbal, recommended capsaicin for shingles several years ago. 

  19. Remember “The Simpsons” when Marge became a cop and Homer kept stealing her pepper-spray to put on his food? “Marge, one squirt and you’re south of the border.”

  20. Chile doesn’t make your “nerve endings shrivel up”. Chile ENHANCES flavor. If you eat heat on a regular basis, your food tastes better, and tastes MORE with it. Habañero chiles, for example, have an astonishingly deep and complex flavor that you can’t taste until you get used to the heat.

  21. I’m delighted the weather is cooling off, because after this post I will be cooking chili tonight. Oh yes. Mmm.

  22. Try mixing Tabasco peppers with sausage, barbecue or swordfish and you’ll find you’re onto something good. The flavor is smoky and rich, like no other pepper. It makes my mouth water just to sit here and write about it.

  23. I’ve become addicted to dave’s ghost pepper sauce… about 650k scoville, and a very clean, fruity almost citrusy flavor. The thing is I’ve been through like 4 bottles over the last 6 months… I really wonder what this stuff is doing to me long term. I’ve developed such tolerance for it that I’ve had to keep increasing dosage to get the same high from it.

  24. Greetings from New Mexico! We make a distinction here …

    “Chili” is what you make with beans, meat, tomatoes, seasonings, etc. “Chile” is the pepper.

    Now … red, green or Christmas?

  25. I think these kind of plasters (chili, belladonna, etc) have been available forever from Chinese groceries. 
    I have  a “vorwerk chilli brand” from Astrabon Ltd. in Singapore in front of me right now.
    Great technology, but not new at all.

    1. I talked once with a Doctor of Traditional Chinese Medicine who oversaw production of tablets with his name on it.  I mentioned that high end supplement makers in the US bragged about organic status or purity of compounds, and that there were reports and concerns about heavy metals in poorly regulated preparations.  He was entirely dismissive, said basically “In China we don’t care about things like that”.   Not saying you can’t do it more cheaply on your own, but you may want to at least source your peppers. 

  26. …and looking at the very medicinal looking packaging above, my guess is that the grocery store brands are a lot cheaper too.

    1. The medication in question is prescription-only and FAR stronger than anything you could buy off the shelf or even make yourself without some serious biochemical know-how. Think of a poppy-seed bagel vs. a shot of morphine.

      1. It is stronger, but not by that much, Vorwerk’s plaster is 3%. 
        There is another product I am familiar with called Lehcare which is even more penetrating, and has capsicum as one of the ingredients. According to the manufacturer they have an oil which can be added to it to make it even stronger – specifically for nerve pain. 
        It is a Canadian product. I don’t know if it is available in the U,S,

  27. I am really interested in this.  My ten year old daughter developed RSD/Complex Regional Pain Syndrome almost a year ago and has not had a day without some degree of nerve pain since the onset.  RSD is considered to be chronic and incurable but many people have achieved a remission of symptoms and desensitization is a big component of getting to remission.  I hope that my daughter’s PM specialist is receptive to trying this treatment.

  28. I took my mother to this Mexican restaurant for some chili cheese steak fries. I found them mildly spicy and added some extra hot pepper sauce to mine. My mother ate hers without the pepper sauce and acted like she was served a bowl of lava. I know I acquired a tolerance for spicy food over the years, but seeing her reaction to something I thought mild was something else.  

    1. What are “chili cheese steak fries”? I googled it but came up with Andy Capp brand packaged snack food, not something you would get in a mexican restaurant. I can imagine french fried potatoes with chili and shredded cheese on top, but where does the steak fit in?

      1. Google “steak fries” to look at some photos.

        It is the name for french fries that are cut into thicker (or wider) slabs than regular fries. They are more substantial than McDonald’s fries, and very similar to British chips.

  29. Shingles folks:  I think you might find that this treatment is rough–since Shingles is a virus that involves nerves themselves, it caused immense pain in my wife.  Ask your Dr. first.  Then ask another Dr.  It friggin’ hurt her.

    Also, capsaicin actually doesn’t cause your nerves to shrivel up.  Effectively, it “hurts” the nerves so much that they stop hurting (okay, it’s a little more complicated than that, but you get the point….).  See “Substance P” and “depolarization” and “hyperpolarization” in neurons and neurology.

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