Metformin is a medication prescribed to help manage type 2 diabetes. Recent research suggests, however, this medication may potentially decrease risk of certain types of skin cancer.

A retrospective case-control study published in the Journal of Drugs in Dermatology explored whether metformin could reduce the risk of non-melanoma skin cancers, specifically basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

What the research says

Researchers analyzed data from the All of Us research database, which compiles health information from a diverse group of participants, to assess the potential impact of metformin on these two cancers.

Metformin reduced the risk of basal cell carcinoma across all sex and ethnicity groups, the researchers found.

For squamous cell carcinoma patients, though, the lines weren’t as clear. In some cases, metformin users saw a significantly lower risk of squamous cell carcinoma, but that reduction was not significant in African American patients.

The results suggest metformin may offer protective benefits against certain types of non-melanoma skin cancers, though its effectiveness may vary among different populations.

It is important to note that metformin’s effect on skin cancer is controversial and researchers do not yet understand how it might work to reduce the risk of certain skin cancers.

Other studies have found that metformin may have an anti-inflammatory effect that lowers the risk of certain skin cancers, but we do not know this for certain.

Side effects of metformin

Metformin is generally considered safe and well-tolerated by most people, though side effects like nausea, vomiting and diarrhea may occur in up to 30% of people taking this medication. Less frequent side effects can include chest discomfort, weakness, headache, rhinitis, hypoglycemia and vitamin B12 deficiency (with long-term metformin use).

A rare but serious side effect is lactic acidosis, with risk factors being older age, having a history of alcoholism and hepatic and/or renal impairment.

Who might benefit?

More research is needed to determine exactly how metformin may or may not help to reduce skin cancer risk. Based on the current evidence we do have, my advice is to discuss the use of metformin with your doctor if you have a history of multiple skin cancers and also a history of high blood sugar.

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