A cheap drug often promoted by podcaster and fitness fanatic Joe Rogan could lower the risk of colon cancer.

A new study found metformin – a 20-cent pill used to manage type 2 diabetes – cut the risk of developing the deadly disease by up to 13 percent.

Israeli researchers tracked 31,000 who took metformin for up to five years. 

In the end, patients who took the drug for three to five years had a 13 percent lower risk of developing colon cancer in the part of the colon most susceptible to tumors. Taking the drug for one to three years was associated with a 10 percent decline in risk.

Participants were from the Veterans Affairs database, and most were over 50 years old, but researchers said their results suggested metformin could potentially be used to help prevent colon cancer for wider groups.

Uncontrolled diabetes is a risk factor for the disease, so treating it in general may lower cancer risk, but using metformin may provide additional benefits, as previous research has shown the drug has been linked to slowed aging and reduced mortality.

Popular podcaster Joe Rogan, 57, who hasn’t revealed if he is taking the drug himself, often talks about the medication on his podcast, with expert guests touting its potential longevity benefits.  

One guest, Harvard anti-aging scientist Dr David Sinclair claimed it could help to slow aging – and in an interview with Dr Sinclair in 2019, Rogan said: ‘I got to find a quack that’s willing to prescribe me metformin.’

A study suggests that metformin, which Joe Rogan has mentioned repeatedly on his popular podcast, could help to reduce the risk of colon cancer on the left side of the colon

Metformin has been approved for type 2 diabetics but is prescribed off label for a range of ailments. Researchers are also looking at whether it could be used to fight aging

The study was revealed at ASCO 2025, the world’s largest cancer conference taking place this week in Chicago, Illinois.

While promising, scientists behind the paper did not provide an explanation as to why the drug may be protective and said their results needed to be confirmed with more research.

Metformin is a prescription-only medication approved for type 2 diabetics to help them control blood sugar levels, with patients taking about two pills per day – sometimes priced at as little as 20 cents a pill. It is estimated that over 19 million Americans are prescribed it each year.

But it is also prescribed off-label for a number of other conditions, including prediabetes and Polycystic Ovary Syndrome, a condition in which women experience cysts on their ovaries.

Scientists from The Jusidman Cancer Center in Israel analyzed data on patients in the Veterans Affairs database from 1999 to 2020.

They recruited patients on metformin and matched them to patients with similar characteristics not on metformin. 

These tended to be less healthy patients, which raises the risk of a colon cancer diagnosis or comorbidity.

In the metformin group, the majority of patients had used the substance for at least five years.

Overall, data was available on the location of the tumor for more than 113,000 patients in the study.

Of these, 13,691 were in the metformin group – including 9,588 (70 percent) who developed colon cancer on the left side of the colon.

Approximately 100,000 people were in the non-metformin group – including 95,000 (95 percent) who developed the cancer on the left side of their colon. 

Colon cancer is increasingly striking young people. Bailey Hutchins of Tennessee (pictured), died of colon cancer at 26 years old

The researchers work was published as an abstract by the American Society of Clinical Oncology and has not been made fully available or peer reviewed. 

However, previously published work has found similar benefits.

A study from 2019 found metformin was associated with an eight percent reduction in colorectal cancer. By location, it was associated with a 14 percent reduction in the risk of cancer in the rectum. 

A 2024 study looked at the expression of HCT116 cells – those found in colon cancer patients. When these cells grow abnormally, it contributes to tumor progression, but metformin altered the expression of these cells.

Results showed the medication upregulated genes that may suppress the growth and spread of colorectal cancer cells. 

Another 2024 study found metformin use was associated with ‘significantly lower’ colon cancer risk in both the colon and rectum – about a 30 percent decline in risk.  

And an increased protective effect was observed in white people and those with obesity. 

Researchers concluded metformin’s benefits ‘likely generalizes to populations with higher underlying risk.’