What is Vitamin B17?

Vitamin B17, also known as amygdalin or its semi-synthetic form laetrile, is a naturally occurring compound found in the seeds of certain fruits like bitter almond, apricot, cherry, nectarin, peach, plum and other members of the Prunus rosacea family. Despite its popular name, Vitamin B17 is not officially classified as a vitamin by modern nutritional science or regulatory bodies like the FDA or WHO. 

Amygdalin is part of a class of naturally occurring compounds known as nitrilosides, which are found in over 1,200 edible plants, including seeds, grains, and legumes. When consumed, particularly in large amounts, amygdalin can break down in the body into several byproducts, including hydrogen cyanide, a highly cytotoxic compound capable of killing cells. This cytotoxic effect has raised significant concerns about the safety of amygdalin as a dietary supplement or therapeutic agent.

Due to these concerns, researchers in the 1950s and again in the 1970s developed a semi-synthetic derivative of amygdalin known as laetrile, aiming to reduce its toxicity while retaining its potential health benefits. Among the most vocal proponents of laetrile was Dr. John A. Richardson (MD), who, along with other researchers, reported a range of therapeutic properties, including its potential use as an anti-cancer agent. Though widely debated, these claims helped fuel global interest in Vitamin B17 as part of alternative cancer therapy protocols.

The History of Vitamin B17: From Discovery to Controversy

Vitamin B17 has a rich and complex history spanning more than two centuries, marked by scientific discoveries, medical controversies, and cultural fascination. From its initial isolation in the 19th century to its hotly debated use in modern alternative cancer therapies, amygdalin and laetrile, has remained a natural compound of interest. Though still controversial, it is seen by some as a potential source of medicine that, if fully understood and properly utilized, could open a new chapter in addressing hard-to-treat conditions like cancer. Let’s dive in.

Amygdalin was first isolated in 1830 by French chemists Pierre-Jean Robiquet and Antoine Boutron-Charlard from bitter almonds (Prunus dulcis) during their investigation of plant-based compounds. It was lataer classified as a nitriloside, a large family of compounds found in more than 1,200 plant species, many of which are components of traditional diets. Nitrilosides are widely known to release cyanide when broken down in the body. 

Building on this discovery, renowned German chemists Justus von Liebig and Friedrich Wöhler later studied the compound further. Their experiments revealed that amygdalin hydrolyzes into three key products: sugar (glucose), benzaldehyde, and prussic acid, which is now commonly known as hydrogen cyanide (HCN). 

The fact that amygdalin releases hydrogen cyanide, a well-known cellular toxin, led to early skepticism among scientists. However, it also sparked intrigue, as researchers began to question whether this unique compound might be harnessed for medicinal use, particularly for targeting abnormal cell growth. It was this dual nature of amygdalin that set the stage for the development of laetrile, later promoted as vitamin B17. 

However, research and information on Vitamin B17 remained dormant until 1952 when American biochemist Dr. Ernst T. Krebs Jr. and his father Ernst T. Krebs Sr. synthesized a modified version of amygdalin called laetrile, short for “Laevo-mandelonitrile”. They controversially coined the term Vitamin B17, proposing that cancer resulted from a deficiency of this so-called "vitamin." 

Krebs claimed that laetrile could target and destroy cancer cells by releasing cyanide selectively in tumors, sparing healthy cells. This mechanism is discussed in the one of the sections below. Although mainstream medicine dismissed the theory, it sparked major public interest, especially among those seeking natural alternatives to conventional cancer treatments.

During the 1970s, laetrile saw a surge in popularity, particularly in Mexico, where clinics operated beyond U.S. regulatory reach. Thousands of patients flocked to border cities like Tijuana, hoping to find a cure where conventional medicine had failed. B17 became a symbol of the natural health movement, with claims of tumor reduction and increased survival being widely circulated. 

Dr. John A. Richardson and the Rise of Clinical Use

Dr. John A. Richardson was one of the most influential figures in bringing Vitamin B17 (laetrile) to national attention during the 1970s, a time when interest in alternative cancer treatments was growing rapidly. A practicing physician in California, Richardson began administering laetrile to cancer patients at his clinic, integrating it with nutritional therapy and holistic care protocols. His approach drew widespread attention, not only because many patients reported improvements in their condition but also because it directly challenged mainstream oncology and federal regulations.

As scrutiny from authorities intensified, Dr. Richardson faced legal consequences for using laetrile, an unapproved substance in the U.S. However, he stood firm in his beliefs and became a vocal advocate for further research and patient freedom of choice. In his co-authored book, Laetrile Case Histories: The Richardson Cancer Clinic Experience, Dr. Richardson documented 62 compelling case studies from his clinic, offering a rare clinical perspective on natural alternatives in cancer treatment. The book remains a foundational resource for those exploring B17 therapy and is still referenced by proponents of integrative cancer care today.

Following the death of his father who had also devoted his life to natural healing, Dr. Richardson carried forward his family’s legacy of helping people find wellness through non-toxic, holistic approaches. He later helped establish the Richardson Nutritional Center, a company dedicated to offering apricot seed products and Vitamin B17-rich supplements. The center continues to serve as both an advocate and resource hub for individuals seeking natural health solutions and education about B17.

FDA Intervention and Scientific Rebuttal

As laetrile gained momentum, it also drew the attention of regulatory agencies. The U.S. FDA, after reviewing available data, banned laetrile in 1977, citing a lack of clinical evidence and the serious risk of cyanide poisoning. The National Cancer Institute (NCI) conducted trials which concluded laetrile was ineffective as a cancer treatment. Subsequent warnings were issued by the American Cancer Society and World Health Organization (WHO).

Despite the ban, Vitamin B17 remains widely used in alternative medicine, often in the form of apricot kernels, supplements, or detox protocols. Advocates, including the Richardson Nutritional Center, argue that it can support the body’s natural healing processes when used properly and under guidance. Meanwhile, critics highlight the danger of unregulated use and the need for more robust scientific evidence.

Sources of Vitamin B17

Vitamin B17, in its natural form known as amygdalin, is found in a wide variety of plant-based foods many of which are part of traditional diets across the world. The highest concentrations are typically found in the seeds or pits of fruits, especially those in the Prunus family. Foods rich in Vitamin B17 as documented by June de Spain in 1976 includes; 

• Kernels or Seeds of Fruits: These contain the highest concentrations of Vitamin B17 found in nature. They include apricot kernels, apple seeds, cherry pits, nectarine pits, peach pits, pear seeds, plum pits and bitter almonds
• Beans: broad beans (Vicia faba), burma beans, lentils (sprouted), lima beans, mung beans (sprouted) and rangoon beans. 
• Nuts: macadamia and cashew nuts. 
• Wild variety of Berries: blackberries, chokeberries, christmas berries, cranberries, elderberries, raspberries and strawberries. 
• Seeds: chia seeds, flaxseeds, and sesame seeds. 
• Grasses: acacia, alfalfa (sprouted), wheatgrass and white clover. 
• Grains: oat groats, barley, brown rice, buckwheat groats, millet, sorghum, rye and wheat berries. 

While some of these foods are considered safe in moderate quantities, consuming large amounts, particularly of apricot kernels or bitter almonds can pose a risk due to the potential release of cyanide during digestion.

How Vitamin B17 May Target and Kill Cancer Cells

One of the most widely discussed claims about Vitamin B17 (amygdalin or laetrile) is its alleged ability to target and destroy cancer cells without harming healthy tissue. This idea, popularized by Dr. Ernest T. Krebs Jr., is based on a concept known as selective toxicity, the idea that B17 activates only in the presence of cancer cells.

According to Krebs, our bodies contain two key enzymes known as rhodanese and beta-glucosidase. Rhodanese is found in healthy tissues throughout the body and can neutralize toxic compounds while beta-glucosidase is found in large amounts around cancer cells. It is almost non-existent in healthy tissues. 

Vitamin B17 is composed of four components: two parts glucose (sugar), one part benzaldehyde (a natural pain reliever), and one part hydrogen cyanide, a compound that becomes toxic when not neutralized.

In healthy cells, the enzyme rhodanese breaks down Vitamin B17 into harmless byproducts like thiocyanate and benzoic acid, which may support cellular health and contribute to vitamin B12 production. However, in cancer cells, where rhodanese is absent and beta-glucosidase is present in high amounts, B17 undergoes a different reaction, releasing hydrogen cyanide and benzaldehyde directly into the tumor, resulting in a toxic effect that destroys the cancer cells. This process, sometimes referred to as selective toxicity, is thought to spare healthy cells while specifically targeting malignant ones.

Research by experts such as Dr. Harold Manner, Dr. John A. Richardson, and Dr. Philip Binzel suggests that Vitamin B17 is most effective when used as part of a comprehensive nutritional and metabolic therapy program. Rather than relying on B17 alone, these researchers recommended combining it with key nutrients that support the body’s healing processes. Zinc plays an important role by helping transport B17 into cells, while magnesium, selenium, and vitamins A, B, and C are believed to enhance immune function and promote cellular repair. In addition, pancreatic enzymes are considered essential, as they form part of the body’s natural defense system against abnormal cell growth. Collectively, this approach reflects a belief that B17 should not be viewed as a standalone cure, but as part of a holistic strategy that includes proper diet, targeted supplementation, enzymatic support, and lifestyle adjustments.

Therapeutic Potential of Vitamin B17: What the Research Really Says

1. Anticancer properties 

The anticancer potential of Vitamin B17 has been widely explored, particularly for its reported ability to inhibit tumor growth, trigger apoptosis (programmed cell death), and enhance immune system activity.

A 2019 study published in the Pakistan Journal of Pharmaceutical Sciences investigated the effects of Vitamin B17 on Ehrlich solid tumors (ESTs) in mice, focusing on tumor progression and organ function. The findings revealed a notable reduction in tumor size and growth rate, along with less fragmentation in the remaining tumor tissue. Additionally, researchers observed that Vitamin B17 lowered biomarkers associated with DNA damage, inflammation (TNF-α and NF-κB), and oxidative stress. 

Another study published in the International Journal of Radiation Biology revealed that amygdalin enhances immune activity, notably increasing the ability of white blood cells to destroy harmful cells. Researchers proposed that Vitamin B17 might stimulate pancreatic enzyme production, which plays a critical role in breaking down potentially cancerous cells. Additionally, the release of hydrogen cyanide in cancerous environments is believed to increase acidity within tumors, damaging malignant cells while leaving healthy cells unharmed. This is an effect referred to as selective toxicity.

Amygdalin has also shown direct anti-proliferative effects across various cancer cell types. In cervical cancer (HeLa) cells, it induced apoptosis through the mitochondrial pathway, while in prostate cancer cell lines, it disrupted the cell cycle, notably reducing the number of cells in the G2/M and S phases. In studies on renal cell carcinoma (RCC), amygdalin reduced the expression of key cell cycle proteins including cyclin B, cdk1, E-cadherin, and N-cadherin, effectively suppressing tumor growth and metastasis.

Laetrile was also reported to inhibit human renal fibroblast activity, particularly by blocking collagenase expression and encouraging cancer cell apoptosis, offering a possible route for preventing kidney-related fibrotic cancer progression.

Further supporting amygdalin’s selective action against cancer, a 2015 study published in Animal Cells and Systems examined its effect on cell growth and telomerase activity in various human cancer cell lines compared to healthy fibroblasts (MRC-5). Researchers found that β-glucosidase activity, the enzyme responsible for releasing cyanide from amygdalin, was significantly higher in cancer cells than in normal cells. At concentrations above 10 mg/ml, amygdalin noticeably inhibited cancer cell growth, induced abnormal cellular aging, and triggered high β-galactosidase activity, an indicator of senescence. Most notably, the study revealed that amygdalin significantly downregulated telomerase activity in cancer cells by reducing the expression of TERT and TERC, key components linked to cancer cell immortality. In contrast, healthy cells remained largely unaffected. 

2. Reducing blood pressure 

Emerging evidence suggests that Vitamin B17 (amygdalin) may have a mild blood pressure–lowering effect, though more rigorous human studies are needed to confirm its effectiveness. One proposed mechanism is the formation of thiocyanate, a known compound that helps reduce blood pressure by dilating blood vessels and promoting better circulation. Additionally, once metabolized in the body, Vitamin B17 interacts with the enzyme beta-glucosidase and intestinal bacteria, triggering detoxification processes that may also contribute to lower blood pressure levels.

A 2011 observational study involving adults aged 40 to 65 reported that consuming apricot kernels, rich in amygdalin, led to an average 28.5% drop in systolic blood pressure and a 25% drop in diastolic pressure. However, the study lacked a control group and was limited in scale, making its conclusions inconclusive. 

3. Anti-inflammatory properties 

Findings from both animal and cell-based studies support the view that Vitamin B17 possesses multiple pharmacological benefits, including anti-inflammatory, antioxidant, antitussive, and even antiasthmatic properties. Beyond its potential anticancer properties, Vitamin B17 has also shown promise as an anti-inflammatory agent. In a study investigating autoimmune hepatitis (AIH), pretreatment with amygdalin was found to reduce inflammation in the liver by significantly lowering the infiltration of CD4+ immune cells, a key driver of tissue damage in autoimmune conditions. The study concluded that amygdalin’s protective effect was largely due to its anti-inflammatory and antioxidant activity, highlighting its potential as a supportive therapy in managing liver-related autoimmune disorders. Additional research has shown that amygdalin may suppress proinflammatory cytokines, particularly pro-IL-1β, a molecule involved in initiating and sustaining inflammation in the body. 

4. Anti-asthmatic effect

Traditionally used in ancient Korean medicine for respiratory issues, amygdalin has been recognized for its anti-asthmatic and antitussive (cough-suppressing) properties. Once metabolized in the body, it breaks down into benzaldehyde and hydrocyanic acid, both of which are believed to slow respiratory movement and reduce airway hypersensitivity. A 2017 review suggests that amygdalin may help suppress type 2 helper T cells (Th2 cells). These are immune cells commonly associated with allergic asthma, thereby inhibiting the Th2-mediated response to allergens and supporting respiratory health.

In addition to its respiratory benefits, amygdalin has shown the ability to enhance the expression of regulatory T cells (Tregs), which play a critical role in maintaining immune balance. This effect has been explored in inflammatory conditions such as psoriasis and atherosclerosis, where amygdalin helped to expand blood vessel lumen area and reduce aortic plaque formation. 

5. Supporting digestion 

Emerging evidence suggests that amygdalin may support digestive health, particularly in conditions involving inflammation of the stomach lining. A study investigating its therapeutic potential in animal models found that amygdalin had a positive effect on rats with chronic gastritis and chronic atrophic gastritis, two conditions associated with long-term inflammation and degeneration of stomach tissue. The study reported improved gastric function and reduced mucosal damage, indicating that amygdalin may help soothe and restore the stomach lining. 

6. Pain relieving properties 

Beyond its anti-cancer and anti-inflammatory properties, Vitamin B17 may also offer natural pain-relieving benefits. Research involving amygdalin extracted from Prunus armeniaca (apricot) demonstrated that it could reduce formalin-induced pain in rats, a widely accepted model for studying chronic pain. The analgesic effect appears to be linked to amygdalin’s ability to modulate inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1), both of which play major roles in pain signaling. The study also noted changes in c-Fos expression, a marker associated with pain processing in the nervous system. 

Nutritional Synergy: Supporting Nutrients That Enhance Vitamin B17’s Effects

Research shows that Vitamin B17 is most effective when used alongside key nutrients like magnesium, selenium, vitamin A, B and C. Zinc was found to play a vital role by helping transport B17 into cells, allowing it to target abnormal growth. Without adequate zinc, laetrile may not function optimally. Other ingredients serve as cofactors which enhance immune response, boost antioxidant activity, and aid tissue repair. Pancreatic enzymes are also essential in B17 protocols, helping break down the protective protein coating around tumor cells, making them more vulnerable to immune attack and improving overall metabolic health.

Safety, Side Effects, and Cyanide Concerns: Is Vitamin B17 Safe?

One of the most debated aspects of Vitamin B17 (amygdalin) is its safety, particularly due to its ability to release hydrogen cyanide when metabolized. This has led to significant controversy in both medical and regulatory circles, with concerns about potential toxicity, especially when consumed in large quantities or without proper supervision.

When B17 is broken down in the body, particularly in the presence of the enzyme beta-glucosidase, which is more abundant in cancer cells, it can release hydrogen cyanide, a known toxic compound. While this is part of the proposed mechanism that targets cancer cells, excessive or uncontrolled exposure could theoretically affect healthy cells as well.

Most reported cases of adverse effects are linked to overconsumption of raw apricot kernels or high-dose laetrile supplements taken without professional guidance. Symptoms of cyanide toxicity can include headache, nausea, dizziness, and in severe cases, respiratory distress.

However, it's important to note that context, dosage, and delivery method matter greatly. Many supporters of metabolic therapy argue that:

• B17 is relatively safe when taken in appropriate doses alongside detox-supporting nutrients like zinc, vitamin C, and pancreatic enzymes.
• Cyanide release is highly targeted, as healthy cells contain rhodanese, an enzyme that neutralizes cyanide into the harmless compound thiocyanate.
• The problem arises when people self-administer large doses without proper monitoring or fail to support their body’s detoxification pathways.

In response to safety concerns, regulatory bodies like the FDA have banned the sale of laetrile as a therapeutic drug in the U.S. and removed Vitamin B17-containing products from mainstream circulation. Still, apricot seeds and amygdalin supplements remain available in some regions as dietary or herbal products, often labeled as “B17 extract” or “nitrilosides.”

As with any supplement, especially one with such potent bioactive compounds, consulting a knowledgeable health professional is essential before beginning any B17 protocol.

Legal Status and Regulatory Controversy

Vitamin B17 remains controversial due to its cyanide content. In 1977, the FDA banned its use in the U.S. for medicinal purposes, citing toxicity concerns and lack of clinical evidence. However, it’s still available in some states under alternative or “Right to Try” laws.

Globally, B17 is banned in countries like Canada, Australia, and most of Europe, while it remains accessible in Mexico and parts of Asia, where alternative cancer clinics still use it. Supporters argue that its natural, non-patentable nature has led to industry resistance and regulatory suppression.

Today, B17 is commonly sold as a dietary supplement or apricot seed product, but it’s not recognized as an approved treatment. As demand grows for natural alternatives, so does the call for unbiased research and clearer global regulation.

FAQ

What is Vitamin B17 used for?

Vitamin B17, also known as amygdalin or laetrile, is primarily used in alternative medicine for its potential anticancer properties. It is believed to help the body target and destroy cancer cells through a mechanism called selective toxicity, while leaving healthy cells unharmed. Additionally, Vitamin B17 has been studied for its potential anti-inflammatory, antioxidant, immune-boosting, pain-relieving, and detoxifying effects. Some proponents also use it as part of metabolic therapy, combining it with nutrients and enzymes to support overall health. However, its use remains controversial and is not approved as a cancer treatment in many countries.

How many apricot kernels can you take a day?

There is no universally agreed safe dosage for apricot kernels, but health authorities generally advise extreme caution due to their natural cyanide content. The European Food Safety Authority (EFSA) warns that consuming just 3 small bitter apricot kernels per day can exceed the safe limit for adults, while for children, even 1 kernel may be dangerous. Supporters of Vitamin B17 often suggest starting with 1–2 kernels per day and gradually increasing under supervision, but this should only be done with guidance from a qualified health professional. Always choose products that are clearly labeled and sourced from reputable suppliers.

What are the benefits of eating apricot kernels every day?

Apricot kernels contain amygdalin (Vitamin B17), a compound that has been traditionally used in pharmaceutical and natural medicine for its potential health benefits. Daily consumption in small, controlled amounts is believed to support the body in managing migraines, relieving constipation, easing asthma symptoms, and reducing high blood pressure. They have also been used in traditional remedies to soothe coughs and enhance brain function. 

Which is better, sweet or bitter apricot seeds?

Bitter apricot seeds contain significantly higher levels of amygdalin (Vitamin B17) compared to sweet kernels, making them the preferred choice in alternative therapies that target cancer or inflammation. However, their high amygdalin content also means they carry a greater risk of cyanide toxicity if consumed in large amounts. Sweet apricot kernels, on the other hand, contain lower and safer levels of amygdalin, and are often enjoyed as a nutritious snack, rich in protein and fiber. The better option depends on your intended use, bitter for therapeutic purposes (with caution), sweet for everyday nutritional benefits.

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