Vitamin B17 refers to a drug called laetrile, an artificial form of amygdalin. Amygdalin is a plant substance present in some nuts, plants, and fruit seeds.

Although people often refer to B17 as a vitamin, this substance does not have approval by the American Institute of Nutrition Vitamins. In addition, the Food and Drug Administration (FDA) does not recognize it as safe.

Some people may take laetrile to treat cancer. However, many experts consider the compound controversial, as no research supports it as an effective treatment and instead links it to potentially severe side effects. Most notably, taking vitamin B17 can cause the body to produce cyanide, a poisonous and dangerous chemical.

In this article, we will discuss vitamin B17, including the possible benefits, side effects, and which foods are sources of the compound.

Vitamin B17 is also known as laetrile, amygdalin, or the scientific name D-mandelonitrile-b-D-glucosido-6-b-D-glucoside. Laetrile is a synthetic drug version of amygdalin, a substance that occurs naturally in small doses in a variety of nuts, plants, and seeds.

A person can take laetrile orally or as an injection intravenously or intramuscularly. Although many refer to this compound as vitamin B17, it is not actually a vitamin.

In 1920, Dr. Ernst T. Krebs, Sr. formulated a theory that amygdalin could be effective against cancer, but it was too toxic for humans. Continuing his research, his son, Ernst T. Krebs, Jr, synthesized a less harmful version called laetrile in 1952. Despite not being a vitamin, he described laetrile as vitamin B17, likely to avoid FDA regulations, which apply to medicines but not vitamins.

Despite this, the FDA issued a statement against laetrile in 1977, indicating that there was no evidence of the safety and efficacy of the drug. Today, manufacturers produce the drug in Mexico, and treatments are available in Mexico and some United States clinics. However, the FDA still does not approve or regulate laetrile, meaning batches of the drug may vary in purity and composition.

Despite a lack of evidence, some people may still consider using vitamin B17 to treat cancer, sometimes as part of a metabolic therapy program. These programs involve high doses of vitamins, a special diet, and pancreatic enzymes.

Most of the research on vitamin B17 focuses on its associations with cancer, while research around its possible health benefits in other areas is sparse. Previous studies on the potential health benefits of the compound have suggested the following benefits:

  • It may lower blood pressure: An older 2011 study on people between 40 and 65 years old found that apricot kernels which contain amygdalin helped lower systolic blood pressure by 28.5% and diastolic blood pressure by 25%. However, this was a very low quality study that did not use a control group, so more research is necessary.
  • It may provide pain relief: Older research on rats indicates that amygdalin may help relieve pain. However, there is a lack of human-based evidence to suggest the effectiveness of amygdalin as a pain reliever.

More research on vitamin B17 is necessary to discover any potential health benefits of the compound.

There is a lack of research in areas other than cancer treatment and insufficient human-based evidence to support any claims of health benefits. This is likely due to the potential adverse effects of using vitamin B17.

When a person ingests vitamin B17, the body converts it into cyanide in the small intestine. If they take the compound orally, 500 milligrams (mg) of amygdalin may contain up to 30 mg of cyanide. Cyanide poisoning can be fatal — a minimum lethal dose of cyanide is approximately 50 mg or 0.5 mg per kg of body weight.

Evidence also suggests that oral amygdalin is roughly 40 times more potent than the intravenous form due to the way it can convert to cyanide in the gastrointestinal tract.

Mild to moderate cyanide poisoning may cause various symptoms, including:

  • headache
  • nausea
  • weakness
  • increased respiratory rate
  • eye and skin irritation

Symptoms of severe cyanide poisoning may include:

The side effects of vitamin B17 may worsen if a person:

  • eats raw almonds or crushed fruit pits
  • takes high doses of vitamin C
  • eats certain fruits or vegetables, such as bean sprouts, carrots, peaches, and celery

People have used vitamin B17 as a cancer treatment since the 1800s, either alone or as part of a program of treatments. However, clinical trials on animals and humans have found no evidence that laetrile is an effective cancer treatment. Evidence suggesting it is effective is largely anecdotal or originates from unsupported opinions.

Some test-tube studies suggest that laetrile may reduce the occurrence of tumors by affecting the genes that help them spread. However, there is no evidence that vitamin B17 would have the same effect in a living human body.

Studies in humans are rare, as not only is vitamin B17 unlikely to be effective, but it can cause serious side effects and even cyanide poisoning.

Amygdalin, the compound that vitamin B17 derives from, can come from a variety of foods, including raw nuts, such as bitter almonds. It can also come from the pips of fruits, such as apricot kernels.

Additionally, foods containing beta-glucuronidase or vitamin C may increase the conversion of amygdalin to cyanide. Therefore, if a person is taking laetrile tablets, they should avoid consuming the following foods:

  • nuts
  • crushed fruit pits
  • raw almonds
  • carrots
  • apricots
  • peaches
  • celery
  • beans
  • bean sprouts
  • flax seed

These foods are generally safe when a person is not taking laetrile, as the levels of amygdalin in them are very low. However, an individual should avoid eating these foods if they are taking laetrile, especially as an oral tablet.

Vitamin B17, also known as amygdalin and laetrile, is not actually a vitamin. Instead, it is a drug derived from plant substances. People may consider using vitamin B17 to treat cancer, but no evidence supports it as an effective treatment and actually highlights the potentially severe adverse effects of its use.

No human studies suggest any benefit of vitamin B17 as a cancer treatment, noting that it can cause cyanide poisoning, especially if a person takes it orally in tablet form. Cyanide poisoning can lead to mild-to-severe side effects and could even be fatal.