The short answer
Laetrile, marketed as 'vitamin B17' or amygdalin, has shown little anticancer effect in studies and is not approved by the FDA. It is not actually a vitamin. It can release cyanide in the body and has caused cyanide poisoning. Cancer authorities do not recommend it, and relying on it instead of proven treatment is risky.
Laetrile ('vitamin B17,' amygdalin) is promoted as a natural cancer cure.
It is not a vitamin, and studies have shown little to no anticancer effect.
It is not approved by the FDA as a cancer treatment.
Laetrile can release cyanide in the body and has caused cyanide poisoning.
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The full explanation.
The claim
Laetrile — a partly man-made form of amygdalin, a substance found in the pits of many fruits and in raw nuts — is marketed as 'vitamin B17' and promoted as a natural cancer cure that is supposedly suppressed by mainstream medicine. It has been sold for decades in various forms.
What the evidence shows
According to the National Cancer Institute, laetrile has shown little anticancer effect in laboratory, animal, and human studies, and it is not approved by the FDA. It is not a vitamin, despite the 'B17' name. Importantly, amygdalin can break down into cyanide in the body, and there have been reports of cyanide poisoning, including serious harm, from laetrile — the risk can be higher when it is taken by mouth or with certain foods or supplements. The way laetrile is made is not regulated, so purity and contents vary.
Why the claim persists
The 'suppressed natural cure' narrative is powerful and has a long history around laetrile specifically. Calling it a 'vitamin' makes it sound safe and essential. Testimonials circulate, but personal stories cannot separate a remedy's effect from the natural course of illness or from other treatments a person received.
The bottom line
Based on the evidence, laetrile/'vitamin B17' is not a proven cancer treatment, and it carries a real risk of cyanide poisoning. Using it in place of effective treatment can be dangerous. If you have seen these claims, talk with your care team about proven options and about the safety of anything you are considering.
Words to know
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Common questions
▸Is laetrile a vitamin?
No. Despite the name 'vitamin B17,' laetrile is not a vitamin. It is a form of amygdalin found in fruit pits and nuts.
▸Does laetrile cure cancer?
Studies have shown little to no anticancer effect, and it is not FDA-approved. Cancer authorities do not recommend it as a treatment.
▸Is laetrile dangerous?
It can be. Amygdalin can release cyanide in the body, and there have been cases of cyanide poisoning. Relying on it instead of proven treatment is also risky.
▸Why is it still promoted?
The 'suppressed natural cure' story and the vitamin label make it appealing, and testimonials spread online — but these are not scientific evidence.
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