Is Vitamin B17 a Natural Cancer Treatment?

Vitamin B17 is a commonly used name for a chemical called amygdalin. Typically sourced from apricot pits and bitter almonds, amygdalin is used to make laetrile—a compound often claimed to aid in the treatment of cancer, despite little evidence of its safety or effectiveness. Although they're frequently referred to as "vitamin B17," amygdalin and laetrile are not actually B vitamins.

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What is Vitamin B17 Used For?

Proponents of laetrile often claim it's an effective natural cancer treatment that also helps protect against high blood pressure and arthritis. Again, little scientific evidence supports these uses.

Laetrile is not approved by the Food and Drug Administration (FDA) as a treatment for cancer or any other medical condition. In fact, as recently as 2019, the FDA issued an import alert for laetrile, citing a lack of evidence for its effectiveness and its status as an unapproved drug.

The National Cancer Institute (NCI) states there is no evidence that laetrile is needed by the body or that laetrile can act as a vitamin in animals or humans.

How It's Claimed to Work

At its core, the hypothesis of B17 as a cancer fighter rests on a mechanism called apoptosis, which is when an infected or cancerous cell commits suicide to protect neighboring cells from the pathogen or prevent itself from dividing and creating more cancer cells. Apoptosis is a way for your body to keep itself healthy.

Proponents of laetrile claim that the cyanide it releases in the body causes apoptosis in cancer cells without damaging healthy cells. This idea has especially been promoted for several types of cancer, including:

Some scientific evidence showing anti-cancer activity with laetrile has renewed interest in it, but so far, evidence is preliminary and needs more follow-up research to gauge its true effects and the potential risks involved.

Some laetrile proponents also claim that cancer is caused by a deficiency of vitamin B17 (which, again, isn't even an actual vitamin). They say that consuming laetrile can reverse this deficiency and, in turn, aid in the treatment or prevention of cancer. This claim is unfounded, as the body has no known uses of B17.

Laetrile's popularity has been maintained and at times bolstered by conspiracy theories. For decades, some people have claimed that laetrile is proven safe and effective and has long been the target of a government cover-up of inexpensive cancer treatments.

Despite the FDA ban that went into effect in 1987, many people still take laetrile for cancer and it's widely available online and in some stores. The products can't legally be marketed as a cancer treatment, but with false claims abounding on the internet, people still learn about the claims and seek it out.

What the Research Says

Some research on laetrile/amygdalin as a cancer treatment, published in reputable journals, does show promise. For example:

In the March 2021 issue of the Journal of Biomelecular Structure & Dynamics, researchers say they uncovered the mechanisms by which amygdalin induces apoptosis—increasing one cellular protein and reducing another—as well as other beneficial actions at the cellular level. They state:

  • "Amygdalin possesses anticancer properties and induces apoptosis."
  • Amygdalyn "can act as a multifunctional drug in the cancer therapeutics."

In the August 2020 Current Molecular Pharmacology, researchers say they demonstrated that amygdalin can kill certain breast cancer cell lines and that amygdalin may prevent those cells from spreading throughout the body. They also state that it wasn't toxic to healthy skin cells.

In a study published in the June 2020 International Journal of Nanomedicine, researchers combined amygdalin with an enzyme called beta-glucosidase (ß-glu), which enhances amygdalin activity, and found that it led to the death of prostate cancer cells. They say the treatment had some impact on heart and liver function but didn't appear to cause organ damage.

Why Evidence Isn't Conclusive

Those studies, and more than a dozen similar ones published in the decade before them, do appear to demonstrate that B17 has a use in cancer treatment. So why isn't that enough?

For starters, it's because they're being conducted on cells in a petri dish or on animals. While that can provide enough evidence for a treatment to move on to clinical trials—involving people—the research hasn't yet advanced to that important stage.

The human body is complex. For a treatment like laetrile to be an effective cancer treatment, it needs to not only effectively kill cancer cells without harming healthy cells, it has to:

  • Be delivered in appropriate and consistent dosages, which haven't yet been established and likely aren't possible through diet or via unregulated commercial products
  • Survive the digestion process and the body's other protective mechanisms and make it into your bloodstream and tissues in high enough amounts to be therapeutic
  • Combine with or be broken down in specific ways by your body's enzymes and other substances to make it useful rather than inactive or harmful

Studies also make it clear that amygdalin is more effective against certain types of cancer than others, and they cite the need for further research to determine what potential role it might play. Even the most positive among them don't recommend ingesting large amounts of substances containing B17.

In addition, how well you respond to it may be influenced by the makeup of your gut microbiota (the mix of bacteria in your digestive system). In one study, researchers wanted to understand why some people taking amygdalin develop cyanide toxicity and others don't, and why it's more common with consumed amygdalin than with injected forms.

They discovered that certain gut bacteria have high levels of the enzyme ß-glu, which converts amygdalin to the toxin hydrogen cyanide (HCN). These ß-glu levels can be influenced by multiple factors, including:

Not all the research into amygdalin as a cancer treatment is positive, either. A review available evidence published in 2016 says:

Blaheta RA, et al.

No convincing evidence showing that amygdalin induces rapid, distinct tumor regression in cancer patients, particularly in those with late-stage disease, is apparent.

— Blaheta RA, et al.

The researchers also said several aspects of amygdalin use "haven't yet been adequately explored, making further investigation necessary to evaluate its actual therapeutic potential."

Claims that laetrile or amygdalin can benefit cancer patients are not supported by sound clinical data, according to a report published in the Cochrane Database of Systematic Reviews in 2015.

It said that none of the previous studies it evaluated were high quality enough to meet the reviewers' criteria. They concluded that consumption of amygdalin carries a considerable risk of serious adverse effects resulting from cyanide poisoning and said:

Milazzo S, et al.

On the basis of the available data, there is neither scientific nor ethical justification for clinical trials with laetrile or amygdalin in the management of cancer at the moment.

— Milazzo S, et al.

Those reviews are a few years older than some of the promising studies; however, clinical trials have yet to be done, safe and effective dosages haven't been determined, and the B17 products that are commercially available aren't proven or regulated. The potential risks of this treatment must be seriously considered, especially given all the unknowns associated with the possible benefits.

As the Cochrane review further concluded, "Due to the risk of cyanide poisoning, the use of laetrile or amygdalin should be discouraged."

Food Sources

If you want to get more amygdalin in your diet naturally, it's not hard to do so. However, don't expect a miracle cure, and don't consume excessive amounts of these foods, as it can lead to cases of cyanide poisoning. Natural sources of amygdalin include:

  • Pits and seeds of apricots, peaches, papaya, and apples
  • Raw almonds
  • Lima beans, mung beans, and butter beans
  • Clover
  • Sorghum
  • Carrots
  • Celery
  • Bean sprouts
  • Nuts
  • Flaxseed

There's no harm in including these foods in your diet as long as it's in healthy amounts. Be sure to include your healthcare provider in any dietary changes you make.

Side Effects and Safety Concerns

Laetrile-containing products have been found to trigger a range of side effects that are quite similar to those of cyanide poisoning, such as:

  • Blue coloring of the skin
  • Confusion
  • Nerve damage
  • Dizziness
  • Droopy upper eyelids
  • Headache
  • Liver damage
  • Low blood pressure
  • Nausea
  • Vomiting
  • Fever
  • Coma
  • Death

Cyanide poisoning is a life-threatening emergency. If you or someone you know is experiencing these symptoms, get immediate medical help.

Much of the laetrile products that are commercially available in the U.S. come from Mexico. These products are untested and unregulated, and contaminated products have been found. These products may pose serious threats to your health beyond those of the laetrile itself.

Vitamin C may boost the amount of cyanide laetrile releases in your body and may lead to an increased risk of toxicity.


While there's no proven way to completely eliminate the risk of all cancers, certain practices may help lower the risk. These practices include:

  • Avoiding smoking and tobacco use
  • Getting recommended screenings
  • Following a healthy diet
  • Exercising regularly
  • Maintaining a healthy weight

If you're thinking of using vitamin B17 for the prevention or treatment of cancer, it's crucial to consult your healthcare provider first. Self-treating and avoiding or delaying standard care can have serious consequences.

Frequently Asked Questions

Where can I buy vitamin B17?

B17 is widely available from online and brick-and-mortal retailers in the U.S. However, its production is unregulated and these products are not FDA approved for any use, nor does the FDA consider these products to be safe.

What does vitamin B17 do for the body?

While there's some preliminary lab evidence that it may help stop the spread of certain cancers, the only conclusively proven effect of so-called vitamin B17 on the body is cyanide poisoning. Among people who use it as a cancer treatment, some die of cyanide toxicity.

A Word From Verywell

Natural products have a real appeal to some people, especially given the side effects that are possible with pharmaceuticals. Cancer treatments especially can be hard on your body. However, it's important to remember that "natural" doesn't automatically mean "safe."

Some natural or alternative treatments may be low-risk enough that even if they don't work, there's no harm in trying them. That's not the case with laetrile/amygdalin/vitamin B17—the cyanide content poses a very real threat to your health. If you're considering it as a treatment, via commercial products or diet, be sure you talk to your healthcare provider first.

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