Capsaicin is what makes chili peppers hot. When topically applied, capsaicin may help relieve pain, while consuming capsaicin may modestly accelerate metabolism. Read on to learn more.
What is Capsaicin?
Capsaicin is the major ingredient in hot peppers [1].
There is a capsaicin receptor expressed by primary sensory neurons in the pain pathway, called the TRPV1 receptor (also called the capsaicin receptor or vanilloid receptor) [2].
Mice that are bred to lack the TRPV1 receptor are unable to sense certain types of pain, such as from heat or inflammation [3].
Mechanism of Effect
Capsaicin may desensitize nerves to sensation. It initially causes an intense excitation of sensory neurons, followed by a longer period of insensitivity to stimuli [4].
Capsaicin may also decrease the amount of Substance P in the spinal cord, but not in the brain. Substance P may be involved in how pain transmits through the synapse [5].
Potential Benefits of Capsaicin
Capsaicin supplements have not been approved by the FDA for medical use. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Possibly Effective For
1) Pain
Topical capsaicin is commonly used for pain relief. In clinical studies, topical application relieved pain associated with nerve damage and arthritis [6, 7, 8].
Talk to your doctor before using capsaicin creams or patches, and do not use them to replace something your doctor recommends or prescribes.
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of capsaicin for any of the below-listed uses. Remember to speak with a doctor before taking capsaicin supplements or using capsaicin creams, and never use them in place of something your doctor recommends or prescribes.
2) Weight Management
Clinical trials have shown that capsaicin:
In rats, capsaicin furthermore decreased appetite by increasing GLP-1 secretion and activating parts of the brain that control appetite [10].
When ingested orally with green tea, capsaicin reduced appetite and food intake in humans. Early research indicates that taking capsaicin as a weight-loss supplement is safe, but more must be known about its effectiveness [9].
Capsaicin increases metabolism by activating TRPV1 receptors. These receptors are responsible for the increasing body temperature as well as pain sensation.
Upon activation, the receptors move calcium into the cells, which furthers the cellular production of antioxidant enzymes, while decreasing proteins known to cause inflammation.
Through this mechanism, capsaicin raises the basal metabolic rate in the gut [11].
This TRPV1 activation provides protective antioxidants in cases of fatty liver disease and high blood sugar [9].
3) Psoriasis
The topical application of capsaicin inhibited the widening of the skin’s blood vessels (cutaneous vasodilation), suggesting [12].
Capsaicin is also thought to reduce scaling and erythema (patchy redness) of the skin [12].
However, some patients may experience burning, stinging, itching, and redness as side effects from topical capsaicin use, although these symptoms diminished or disappeared with continued use [12].
4) COPD & Emphysema
Recent studies have tested subjects’ responsiveness to inhaled capsaicin with respect to their level of cough. Several different studies were performed on those who suffer from diseases such as asthma, COPD (chronic pulmonary lung disease), and emphysema [13, 14].
In diseases such as COPD, it is noted that chronic cough occurs from the accumulation of mucus. While cough responsiveness due to inhaled capsaicin differed across disease thresholds, the capsaicin itself helped to break up mucus and relieve phlegm [13, 14].
In turn, the use of capsaicin made the cough associated with chronic lung conditions less frequent and less painful [13, 14].
Some people notice that when they eat cayenne pepper, they can cough out mucus better.
5) Burning Mouth Syndrome
In 23 patients, topical capsaicin relieved burning mouth syndrome (BMS), although capsaicin’s naturally irritating quality may have an adverse effect on some users [15].
Animal & Cell Studies (Lacking Evidence)
No clinical evidence supports the use of capsaicin for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
6) Cardiovascular Health
In mice, capsaicin delays stroke occurrence by increasing nitric oxide in the blood vessel (eNOS). This increase in eNOS, in turn, is associated with increased lifespan in mice [9].
Capsaicin also lowers blood pressure in rats prone to hypertension. In addition, it blunts the nighttime rise in blood pressure from a high-sodium diet. Capsaicin may do this by reducing sodium retention by the kidneys [9].
Capsaicin is also known to externally dilate the coronary arteries of pigs. However, the direct application of capsaicin on the muscles that line the blood vessels promotes constriction. This shows the net effect varies, and as such, the interactions are very complex [9].
7) Stomach Ulcers
Capsaicin prevents stomach ulcers in animals, and may also help heal existing ones. Capsaicin inhibits gastric acid secretions, reduces acidity, promotes mucus secretion, and stimulates gastric blood flow [16].
Capsaicin slows stomach tissue damage and bleeding in animals [9].
Cancer Research
Capsaicin is under investigation in the context of the following cancers:
Cellular or animal studies that show promise against cancer don’t often translate to any cancer benefits in humans. Further research and large clinical trials are needed to determine if capsaicin can be useful as a treatment for cancer [20].
Side Effects & Safety
The most common reported side effects of capsaicin use are skin irritation and a burning sensation. In many cases, these instances disappear within a few days of use. If conditions persist, it is always wise to contact a doctor before continuing use.
Capsaicin may cause CNS (central nervous system) depression in some patients. For this reason, users should not operate machinery or drive a car until they are aware of how their body reacts to this treatment.
There have been no adverse effects associated with pregnant women, but capsaicin safety has not specifically been investigated in pregnant women. We, therefore, recommend talking to your doctor before using capsaicin creams if you are pregnant [22].
Clinical trials show that capsaicin, when applied topically, is responsible for the degeneration of nerve fibers close to the skin, affecting blood vessels and sensory function [23].
Damage to the skin’s cutaneous nerve fibers is often responsible for nerve injuries such as meralgia paresthetica, cutaneous nerve entrapment system (ACNES), and other nervous system disorders.
Marketed as Qutenza, high-dose capsaicin treatment is effective at relieving severe nerve pain in clinical trials and was therefore approved by the FDA as a viable treatment. Patients who suffer from severe neuropathy or nerve pain would be wise to suggest high-dose capsaicin to their physician as a viable form of treatment [23].
To avoid adverse effects or unexpected interactions, talk to your doctor before using it.
Supplementation
Dosage
There is no safe and effective dose of capsaicin for any health purpose because no sufficiently powered study has been conducted to find one.
The most common administrative forms of capsaicin include creams, patches, and gels. Capsaicin is administered to both children and adults. The product is sold under many different brand names and forms. It is always best to read a label fully before application.
Proponents recommend that healthy adults apply the 0.075% cream up to four times per day, or apply the 0.025%, 0.03%, 0.0375%, or 0.05% patch for up to eight hours for pain relief. The patch application should not exceed more than five consecutive days.
Normal children over the age of 12 can refer to adult dosing when applying the medication.
