Independent reviews of published studies, graded by evidence level. None of these supplements or drugs is proven as a cancer treatment.
Supplement and pharmaceutical evidence, held to the same standard, on the same page.
Dr. Johnston looks at studies linking obesity to cancer and examines whether GLP-1 medications are associated with lower cancer risk, noting that the evidence is observational.
Dr. Johnston ranks the ten supplements and repurposed generic drugs he would put on his own shortlist, weighing human trials first, then animal and laboratory research.
Dr. Johnston looks at what studies in animals and people report about gut bacteria, probiotics and the response to cancer immunotherapy.
Recurring formats from the Institute, built for depth over headlines.
Dr. Johnston reviews a 2024 study of 1.65 million people with type 2 diabetes in which GLP-1 use was associated with lower risk of 10 of 13 obesity-related cancers compared with insulin, a 2025 comparison with bariatric surgery, and a laboratory finding involving natural killer cells. The studies are observational and cannot prove GLP-1 drugs prevent cancer.
Dr. Johnston reviews a 2025 observational study of more than 86,000 matched adults with overweight or obesity, with and without diabetes. Cancer rates were lower among GLP-1 users, including 17% lower relative risk overall. He notes the study cannot prove GLP-1 drugs prevent cancer.
Dr. Johnston describes a 2025 analysis of 21 prospective studies, with over 108,000 cancer cases and 10,000 deaths, linking higher blood lycopene to lower cancer mortality, lung cancer death and breast cancer incidence. He also cites lab findings. The data are observational, so they show association only.
Supplements referenced in Verity's reviews and recommended by the Institute.
A resource listed by VHI. USP-grade methylene blue capsules formulated for non-stimulant energy and mental clarity, made by Nutricel.
A small healing retreat offering overnight lodging and individual wellness services.
Dr. J.P. Johnston spent three decades practicing family medicine before retiring in 2024. During the COVID-19 pandemic, he prescribed evidence-based supplements and repurposed medications to thousands of patients.
Promising medical research does not always translate quickly into clinical practice—particularly when it involves inexpensive supplements, existing medications used for new purposes, or therapies that lack FDA approval for a particular disease.
Dr. Johnston leads Verity Health Institute’s effort to bridge that gap by bringing published medical research on cancer and other diseases directly to the public. VHI examines the evidence, explains what the research actually found, and gives people the information they need to have better-informed conversations with their healthcare providers.
Other healthcare professionals also contribute their experience and expertise to VHI’s educational mission.
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