Chilli peppers for pain relief and other health concerns

Capsaicin is a compound found in chilli peppers and is a hot topic in scientific research as a potential for many therapeutic uses. It has been shown to reduce the sensation of pain, stimulate metabolism, offer digestive support, and help with blood sugar control, amongst other things.

In western herbal medicine capsicum is used to improve peripheral blood circulation, for pain relief, gastrointestinal disorders and function. It contains constituent with antioxidant activity and may offer antimicrobial action.

What is capsaicin and how does it work to reduce pain?

Capsaicin is a compound found in chilli peppers (Capsicum annum - chilli pepper, cayenne pepper, capsicum). It is responsible for their burning and irritant effect. Much of the identifiable action is due to the pharmacological effects of capsaicin through the nervous system. Other significant constituents also provide significant actions. Nutritional ingredients include high amounts of vitamin A, C, and E. It also contains vitamin B, iron, calcium, potassium, magnesium, phosphorus and sulphur. Its actions include:

• Internally as a stimulant (circulation, metabolism), spasmolytic (relieves smooth muscle spasms – lowers blood pressure and relaxes digestive cramps, for example), diaphoretic (increases perspiration) and a carminative (calms and soothes – digestive discomfort by preventing or expelling gas from the stomach).
• Externally as a rubefacient (increases circulation), antiseptic and counter-irritant (an agent which produces a superficial irritation on one part of the body in order to relieve irritation in another.

How does it work to reduce pain?

When applied topically to the skin often leads to reversible selective loss of nociceptive nerve endings. Nociceptors initiate the sensation of pain. They are free nerve endings (sensory neurons) that respond to damaging or potentially damaging stimuli, located all over the body including skin (peripheral nerves), and also muscles, joints, and internal organs.

The spinal cord and central nervous system are where they perceive pain from internal tissues.

Nociceptors are very sensitive and their primary role is to protect the body from tissue trauma or non-noxious stimuli which would damage tissue if exposure was prolonged. Think the quick reaction by the body when exposed to heat (such as touching a hot oven) or something sharp. The pain felt (due to nociceptors) protects the body from damage.

The application of capsaicin

The application of capsaicin leads to a burst of action, (actually action potentials), which results in profound sensation of burning, stinging, and pain. Sounds awful doesn’t it, but what follows is a reversible desensitization which can potentially last for several weeks where the nerve fibres are effectively anaesthetized. This affect provided by capsaicin is referred to as “defunctionalization”. where the nerve fibres are effectively anaesthetized.

What conditions can capsaicin help with?

Nerve pain (Topical application)

Post-herpetic neuralgia. This type of neuralgia can occur after a bout of shingles. The herpes virus causes inflammation of the nerve and the pain occurs in the same area as the shingles rash. The pain may linger long after the rash has dissipated.

Diabetic neuropathy - pain caused by nerve damage in people with diabetes.

Capsaicin and Obesity

Obesity is a risk factor for many serious health-related conditions such as type 2 diabetes mellitus, coronary heart disease, hypertension, and cancer. The need for effective therapeutic strategies to treat obesity is important to help lower this risk factor. Numerous studies have proven the effectiveness of capsaicin in its ability to promote weight loss. It does this by reducing appetite, promoting satiety and fullness, thermogenesis (the generation of heat), increased fat mobilisation and increased energy expenditure.

Capsaicin and Diabetes

Not only does capsaicin stimulate metabolism, animal studies have reported beneficial effects on glucose and insulin balance (homeostasis).

Capsaicin and Cardiovascular system

There are many capsaicin-sensitive sensory nerves in the cardiovascular system which regulate functions. Capsaicin stimulates the release of powerful vasodilators and plays an important role in blood pressure regulation. It offers cardio-protective effects and has been shown to inhibit platelet aggregation (the process by which platelets adhere to each other at sites of vascular injury).

Allergic rhinitis and asthma

Nociceptors play important role in airway diseases, such as allergic rhinitis and asthma, associated with inflammation. They play a role in the immune system by alerting the body to potential environmental danger and promoting responses.

In the case of non-allergic responses, too much is not always a good thing. Reducing the activity of nociceptors, such as through the use of capsaicin, can reduce inflammatory responses associated with airway disorders.

Non-allergic rhinitis causes symptoms such as obstruction and rhinorrhoea in response to non-infectious triggers such as changes in weather, cigarette smoke and caustic odours. Intranasal application of capsaicin has beneficial effects in this type of rhinitis.

Other conditions include:

• Itch associated with allergy or uraemia
• Cluster headaches
• Arthritic pain
• Urinary bladder hypersensitivity or hyperreflexia
• Gastric disorders - Capsaicin possesses bactericidal activity and was shown to inhibit H. pylori growth (a bacteria associated with gastric ulcers) in vitro, which may contribute to its protective effect.

Topical capsaicin for pain relief

Capsaicin cream can be used topically on areas of nerve pain, such as post-hepatic pain and diabetic neuropathy. By acting on substances in the body which are involved in the transmission of pain impulses from nerve endings near the skin and joints - to the brain, pain can be reduced or blocked completely. Regular use is needed.

Chilli in the diet 

It is the capsaicin in the chilli which gives it the kick, with the seeds containing the highest amount. Capsaicin stimulates the pain receptors on the tongue often producing the sensation of heat. For some people this sensation is not pleasant. The more that is consumed, the lesser the sensation.

Supplemental form of capsaicin are usually obtained from cayenne peppers (capsicum annum).  

Cautions and contradictions

The repeated application of capsaicin can cause an intense burning sensation even at low doses. In some cases, a pre-treated or combined with a local anaesthetic may be needed (as advised by a healthcare provider) to avoid initial discomfort.

Gloves use can be of benefit when applying to areas of pain (other than hands of course) to avoid irritating fingers – and transferring to sensitive areas such as eyes, mouth and genitalia. Or wash hands thoroughly after use with soap and water. 

Do not use on active shingles or open skin.

As with introducing any new product in supplement form, a discussion with a healthcare provider is recommended to ensure the product is right for you.

References

1. Capsaicin https://www.ncbi.nlm.nih.gov/books/NBK459168/
2. Nociceptors - Neuroscience - NCBI Bookshelf (nih.gov)
3. Nociceptor - an overview | ScienceDirect Topics
4. Herbal Medicine for Pain Management: Efficacy and Drug Interactions https://www.mdpi.com/1999-4923/13/2/251/htm
5. Capsaicin: Current Understanding of Its Mechanisms and Therapy of Pain and Other Pre-Clinical and
6. Clinical Uses https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6273101/
7. Capsaicin and menthol in the treatment of itch and pain: recently cloned receptors provide the key https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1773799/
8. Chronic Pruritus: Current and Emerging Treatment Options https://pubmed.ncbi.nlm.nih.gov/28466423/
9. https://www.nps.org.au/medicine-finder/zostrix-hp-cream
10. Fisher, Carole; 2009, MATERIA MEDICA OF WESTERN HERBS, Vitex Medica, New Zealand