This is a myth.
The rumor that capsaicin, the ingredient that gives chili peppers their spicy kick, can actually cause cancer is another case of media fumble and bumble.
The rumor originated when the journal Cancer Research published an animal study analyzing the carcinogenic effects of topical capsaicin on skin cancer. Lead by professor Ann Bode of the Hormel Institute at the University of Minnesota, the study may initially seem to indicate that when applied topically, capsaicin could potentially increase a person’s risk of developing skin cancer instead of being a skin cancer prevention. 
When looking at the actual results of the study, however, it becomes clear that such a threat is unsupported.
Researchers separated mice into two groups: A control group in which ONLY capsaicin was applied to the mice’s skin and a variable group in which capsaicin mixed with additional substances was applied.
The variable group of mice did indeed develop tumors and experienced increased levels of an inflammatory enzyme known as cyclooxygenase-2. Researchers theorize that it is the inflammation that may be triggering the tumors, as opposed to capsaicin contributing a direct effect.
The declaration that capsaicin could be used as skin cancer prevention is also called into question when we analyze the substances with which it was mixed. The formula also consisted of DMBA (7, 12-dimetylbenz(a) anthracene) and TPA (12-O-tetradecanoylphorbol-13-acetate), two known cancer-causing, tumor-promoting drugs. One can safely assume it was not the capsaicin, but the known carcinogens that stimulated tumor production in the mice.
The fact that the control group of mice who received pure capsaicin did not get skin cancer further refutes the rumor that capsaicin could perhaps cause skin cancer. The Hormel Study does not directly link capsaicin to skin cancer prevention – that myth has been propagated by media mismanagement – but instead maintains that, “capsaicin alone does not act as a carcinogen.”
It is also important to note that the rumor only pertains to capsaicin when applied topically, not to capsaicin when administered internally, such as with food or supplements.
The Numerous Benefits of Capsaicin Along with Skin Cancer Prevention
Let’s not give up on this spice because of unfounded rumors. Consider capsaicin’s numerous other benefits:
- Boosts circulation
- Reduces headache pain
- Treats psoriasis
- Stimulates hair growth
- Reduces appetite
- Burns calories
- Destroys cancer cells
Best known as a cancer cure, capsaicin turns up the heat on cancer cells, effectively causing them to self-destruct, a process known as apoptosis. The American Association of Cancer Research reports on numerous studies that demonstrate its ability to kill cancer cells, including one study that showed how capsaicin killed 80% of human prostate cancer cells.
Another study published in the journal Oncogene in 2009 found that capsaicin suppressed the development of breast lesions in mice, reducing tumors by 50%. Studies in Japan and China attest to capsaicin’s ability to slow down the growth of leukemic cells, and a University of Nottingham study confirmed that capsaicin stimulates apoptosis in human lung cancer cells.
Capsaicin is able to destroy cancer cells for skin cancer prevention because it connects to proteins in the mitochondria of the cancer cells, causing death without harming healthy cells.
As a topical treatment, capsaicin alleviates pain by deactivating the neurotransmitter (substance P) that sends pain messages to the brain via the nervous system. It appears that that you won’t need to give up on this topical pain treatment after all.
To reiterate: There is no evidence to support the claim that capsaicin causes skin cancer, while there is a plethora of proof that the spice is an effective cancer buster. Capsaicin, a popular ingredient used in pepper spray and as a chemical agent of pest control, can be dangerous in spray form, but is safe to take internally and applied as a topical cream.
