Laetrile is a drug created in 1952 by Dr. Ernst Krebs Jr., and not a vitamin or amygdalin as it is wrongly labeled. Although some reports claim that it might help treat cancer, there is no evidence for this, rendering it ineffective.

Laetrile is a controversial alternative cancer treatment drug that’s wrongly marketed as vitamin B17 or amygdalin, the primary ingredient found in it. It was popular in the US until when the Food and Drug Administration banned it because of the serious cyanide-poisoning-side effects related to its administration. Besides, there is no evidence that it can effectively treat cancer, and the existing studies show that it only worsens cancer symptoms alongside the serious side effects it triggers. The creator could have named it vitamin B17 to label it as a supplement and not a drug since the strict regulatory standards do not apply to supplements. Here is everything you need to know about laetrile.

Understanding laetrile

First things first, let’s define what laetrile is. Although it is wrongly labeled as vitamin B17 or amygdalin, laetrile is a controversial cancer-treatment drug. It was created by D. Ernst Krebs Jr., who had previously worked on vitamin B15 or pangemic acid, and labeled it as a supplement. Amygdalin is not the same as laetrile but is the primary ingredient therein. Pits of apples, cherries, pears, and plums, vegetables such as carrots, celery, etc., beans, including lima and butter beans, seeds such as buckwheat and millet, and raw nuts, including macadamia, almonds, and raw forms of these nuts are the main dietary sources of amygdalin.

Although Dr. Ernst Krebs Jr. championed laetrile so much as an alternative treatment to cancer, no studies can support this. Rather, as laetrile passes through the blood, enzymes act on it and break it down to hydrogen cyanide, a compound with many dangerous side effects. It primarily deprives cells of oxygen, killing them eventually. When the FDA realized the serious effects related to this drug and its ineffectiveness for cancer treatment, it banned it and has since then not been in use. Laetrile is available as pills or injections, and most of the side effects are related to the pills and augmented by vitamin C or taking the drug with any of the foods containing laetrile. Some studies show that amygdalin, the primary ingredient in laetrile, could help relieve inflammation and pain and lower blood pressure, but all these claims are only supported by weak evidence.

How laetrile interacts with the body and works

The primary reason behind FDA imposing a ban on laetrile is how it interacts with the body to trigger effects, especially side effects. When it gets to the body, enzymes act on and break it down into three compounds, prunasin, benzaldehyde, and hydrogen cyanide which could have the purported anti-cancer properties. Interestingly, the same hydrogen cyanide triggers all the cyanide-poisoning-like side effects of laetrile.

Four theories could explain why laetrile could have anti-cancer properties, but they all lack supporting evidence or trigger negative side effects. One theory claims that all cancers are caused by vitamin deficiencies, and since vitamin B17 or amygdalin was the only one missing in the picture, supplying it could prevent cancer. However, there is no evidence that amygdalin is indeed a vitamin, the body cannot suffer from its deficiency, and neither is it found naturally in the body. The other theory claims that laetrile changes into hydrogen cyanide which then acidifies cells, causing their death. Besides lacking evidence, this action claimed by the theory would kill bad and good cells indiscriminately. The other two theories claim that cancer cells have enzymes that act on laetrile to convert it into hydrogen cyanide, which kills them. These, too, are not scientifically backed up like the first two theories.

Potential benefits of laetrile

Initial studies have focused on laetrile and its effects on cancerous cells but not other conditions. However, amygdalin, the main component in laetrile, has some potential benefits, including;

  • It may promote immunity by causing immune cells to withstand the harmful fast-replicating cancerous cells
  • It might relieve pain, particularly among arthritic patients
  • It may lower blood pressure, as in one study where it caused a drop in systolic and diastolic blood pressures by 28.5% and 25%, respectively

Although the benefits above are quite promising, there is a need for further studies, especially because the shreds of evidence are weak. Until then, we cannot recommend laetrile for those benefits.

Laetrile is not a vitamin

Although laetrile is wrongly called amygdalin or vitamin B17, it is none of that. Instead, it is an original drug that Dr. Ernst Krebs Jr. designed, and he gets the credit for that. His reasons for naming it vitamin B17 or amygdalin are best known to him. However, it could be that he did so because the stringent regulatory rules governing the pharmaceutical industry did not apply to supplements. As vitamin B17 or amygdalin, laetrile would be labeled as a supplement, thereby evading the regulations. However, the truth became evident with time, especially after the drug resulted in serious side effects among those who used it.

Does laetrile treat cancer?

Although Dr. Ernst marketed laetrile as a cancer-treatment drug, studies are inconclusive or reveal no connection between cancer treatment with laetrile. Rather, its administration only results in more side effects. Since hydrogen cyanide is the anti-cancer compound in laetrile, studies have focused on examining its interaction with cells. Animal studies showed worsening cancer symptoms with laetrile administration, and the only two studies involving human beings have reported cyanide poisoning or cancer spreading. At the same time, people who took laetrile as a pill (as well as an injection) experienced symptoms similar to cyanide poisoning, including nausea, vomiting, abnormally low blood pressure, liver damage, droopy eyelids, bluish skin exacerbated by oxygen deprivation, dizziness, and headache. The studies also observed that eating amygdalin-rich foods like raw nuts, certain vegetables, and fruit pits, taking laetrile as a pill, and excess vitamin C intake while taking laetrile worsened the symptoms.


Although laetrile was introduced as an alternative treatment to cancer, it should be banned. It is not only ineffective but results in serious side effects related to cyanide poisoning. Besides, the theories supporting it lack scientific evidence, necessitating the need to avoid it.

For the past years, Tatyana has worked as a sex blogger and a relationship advisor. She has been featured in magazines such as Cosmopolitan, Teen Vogue. Vice, Tatler, Vanity Fair, and many others. Since 2016, Tatyana has focused on sexology, attended various training courses, participated in international conferences and congresses. “I wish people would address sexual issues in a timely manner! Forget shyness, prejudice and feel free to see a sex doctor for help or advice!” Tanya enjoys pursuing her flare for creativity through modelling, graffiti art, astronomy, and technology.

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