Metformin and increased cancer survival

Metformin and increased cancer survival

Metformin may have several actions against cancer as it reduces blood glucose, inhibits insulin and IGF-1 production, reduces cholesterol and has an indirect effect on reducing m-TOR levels; a specific study on breast cancer suggests increased survival times.

In 2016, researchers from the Perelman School of Medicine, Pennsylvania showed that breast cancer patients who started taking metformin after their diagnosis were almost 50% more likely to survive than non-users. Lead Author Yun Rose said that they also looked at people who were already on metformin at the time of diagnosis and those people tended to be poor survivors possibly because they had chronic illness prior to diagnosis.

Five ways Metformin may fight cancer

The use of metformin as a cancer preventative aid is highly controversial. But increasingly, some cancer oncologists are turning to metformin as an anti-cancer drug. Here we look at its possible benefits:

  1. Metformin has proven action in lowering blood sugar. It does this by reducing the ability of the liver to release glucose(1). Metformin actually accumulates in the liver.There can only be a few remaining quacks who deny that cancer cells not only mop up all available sugar, but they even rob healthy cells of theirs and change the insulin production system in the body to keep blood sugar available for their avarice. There is now too much research to argue against.

Go to: 20 research links between sugar and cancer

  1. Metformin also lowers circulating levels of insulin(2), which has proven links to inflammation in the body via the COX-2 pathway. And inflammation aids metastases.
  2. Metformin lowers circulating levels of Insulin-like Growth Factor 1. Or IGF1, which plays a part in cancer development
  3. Metformin indirectly inhibits m-TOR. Eating a big meal leads to increased plasma levels of insulin and IGF-1. In turn these stimulate phosphoinositide 3-kinase (PI3K) and Akt and protein kinase B (PKB), which stimulate m-TOR, an important signaling pathway in cancer such as melanoma(4).
  4. Metformin also reduces fatty liver and lowers blood cholesterol levels(3). Heightened levels of blood cholesterol are linked to greater metastases in cancer patients.

Go to: Fat and cancer spread

Chris Woollams, former Oxford University Biochemist and a founder of CANCERactive added, "Many of the specific studies on metformin have been with patients who have type-2 diabetes, and concern reduced risk of cancer. For example, a 2018 study that Type-2 diabetes patients who took metformin had a lower risk of colorectal cancer (5). A previous study had shown a decreased risk of 54% in those taking metformin vs those not taking. Metformin is known to inhibit certain cancer cell lines. For example, metformin has been shown to inhibit brain cancer GBM cell lines in vitro, and also to have action in vivo(6). Clearly research is in its infancy. We need to know more".

Dose of metformin in cancer

Professional expertise should be sought. Metformin usually comes in 500 mg pills and patients take 2-4 per day.


Side by side research has shown that the herbal ingredient, Berberine, is just as regulatory of blood glucose as metformin in type-2 diabetes. Berberine has been shown in several studies to attack the AMPK pathway; and berberine is anti-microbial and anti-inflammatory.  There is even research that metformin and berberine can complement each other.

Go to: a review on Berberine as a cancer treatment 



  1. J Clin Endocrinol Metab. 2003 Mar;88(3):1323-32.
  2. Nat Med. 2000 Sep;6(9):998-1003.
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