Vitamin B17 and Cancer: When “Alternative Medicine” Becomes Liver Poison
If you are a cancer patient exploring alternative treatment for cancer, you may have encountered "Vitamin B17", often promoted in integrative medicine and CAM settings as a natural cancer cure. Despite the comforting name, "Vitamin B17" is one of the most persistent cancer myths in alternative medicine — and one of the most dangerous, especially during chemotherapy or other cancer therapy as it damages your liver and your ability to withstand other medications.
What Is Vitamin B17, Really?
"Vitamin B17" is not a vitamin. It has no essential biological role and no deficiency state. The compound sold as vitamin B17 is amygdalin, or as a synthetic known as laetrile, which is found in bitter almond pits. Chemically, amygdalin breaks down into cyanide when metabolized.
Calling it a vitamin is marketing, not science based. Your body does not need it, and it never has, and never will.
Why Vitamin B17 Is Dangerous During Cancer Treatment
Once amygdalin enters the body, it is processed by the liver. During this process, cyanide is released. Tumors, including those in breast cancer, prostate cancer, lung cancer, colon cancer, and GBM, receive very little of this compound due to poor blood supply. The liver, however, receives almost all of it.
This means the poison goes to your liver — not your tumor.
Cyanide does not selectively target cancer cells. Instead, it damages your primary metabolic organ, increasing the risk of liver damage at a critical time when your body needs full metabolic support to tolerate chemo, radiation, or other treatments for cancer.
Oral Vitamin B17 Is Even More Harmful
Many people assume IV treatments are riskier than pills. With vitamin B17, the opposite is true. When taken orally, gut enzymes release the cyanide immediately, sending highly concentrated toxin straight to the liver through first-pass metabolism.
This results in higher liver toxicity from pills than from IV infusions, this is consistently seen in all clinical trials. Combining vitamin B17 with vitamin C further accelerates cyanide release and increases the risk of serious injury or death.
Has This Been Studied?
Yes — extensively. Amygdalin cancer claims have been studied for over 100 years. Multiple clinical trials, including Mayo Clinic–led studies, show no survival benefit, no tumor response, and consistent toxicity. The biology aligns perfectly with the clinical data: cyanide harms the patient, not the cancer.
Why Is Vitamin B17 Still Offered?
Some integrative and functional medicine clinics continue offering outdated therapies. While some complementary approaches can support cancer treatment, vitamin B17 is not one of them. It was debunked decades ago and persists only through repetition and marketing.
The Bottom Line
Vitamin B17 is not a cancer cure. It is a cancer myth that exposes patients to unnecessary liver damage while offering no benefit. During cancer therapy, weakening your liver weakens your ability to survive treatment.
Good integrative care means separating what helps from what harms — and biology always wins.
Accurate science saves lives — and it starts with rejecting simple myths in favor of real understanding. Stay curious.
Disclaimer: This content is for educational purposes only and is not medical advice. It does not replace guidance from your healthcare provider. Cancer and treatment decisions are highly individual—always consult your physician or qualified healthcare professional regarding your specific situation.
A full disclaimer is available Terms and Conditions.