Laetrile / 'Vitamin B17'
Amygdalin (apricot kernels)
A discredited 'cancer cure' that releases cyanide.
Evidence tier
No Evidence
Research weight
Not supported
Citations
17 verified / 17
Classification
Debunked
⊘
What the evidence says. No credible human evidence supports the marketed claims — widely considered ineffective.
⚠
Health warning. Laetrile/amygdalin ('vitamin B17') is not a vitamin, has no proven anticancer effect, and breaks down into cyanide in the body — causing real poisoning. It is not approved and is dangerous.
What is Laetrile / 'Vitamin B17'?
Laetrile / 'Vitamin B17' (Amygdalin (apricot kernels)) is a debunked supplement marketed for 'natural' cancer cure. NutriDex grades the human evidence as No Evidence. Laetrile, marketed as 'vitamin B17' (it is not a vitamin), is a semi-synthetic form of amygdalin from apricot kernels promoted as a natural cancer cure. A Cochrane review found no reliable evidence of any anticancer benefit, while the compound metabolizes into cyanide, posing a genuine poisoning risk. The FDA has never approved it, and selling it as a cancer treatment has led to prosecutions.
Marketed Claims (unproven)
✕(Claimed) 'natural' cancer cure
Dosing & Compounds
Use & Legality
No safe dose — it releases cyanide. Not an approved treatment.
Active Compounds
Safety & Cautions
⚠ CYANIDE RISK. Amygdalin breaks down to cyanide, causing nausea, headache, dizziness, liver damage, low blood pressure and potentially fatal poisoning — risk is higher with oral use and vitamin C. Using it in place of proven cancer therapy can be fatal. Not approved or legal as a treatment. Educational only — always check with your doctor or pharmacist before combining Laetrile / 'Vitamin B17' with any medicine.
Evidence & Risk Findings ★ 17 studies
Cochrane review
Milazzo 2015 (Cochrane)
✓ Full text
No reliable evidence of benefit; risk of serious cyanide toxicity.
Systematic review
Milazzo & Horneber (Cochrane Review) 2015
✓ PubMed
Updated Cochrane review searching 8 databases found NO randomized or quasi-randomized controlled trials meeting inclusion criteria; concluded claims of anti-cancer benefit are unsupported by sound clinical data and that the risk-benefit balance is 'unambiguously negative' given the considerable risk of cyanide poisoning, especially after oral ingestion.
agency assessment
EFSA CONTAM Panel 2019 (Scientific Opinion)
✓ Full text
EFSA established an acute reference dose for cyanide from cyanogenic glycosides of 20 micrograms/kg body weight, underscoring the narrow safety margin for amygdalin-containing products such as apricot kernels.
guideline
EFSA CONTAM Panel 2016 (Scientific Opinion)
✓ Source
EFSA's apricot-kernel-specific opinion concluded that, against an acute reference dose of 20 micrograms cyanide/kg body weight, adults can safely eat at most ~3 small raw kernels (370 mg) at one time while a single small kernel already exceeds the safe level for toddlers, flagging acute cyanide-poisoning risk from amygdalin.
guideline
Cancer Research UK (position statement)
✓ Source
Authoritative cancer body states there is no reliable evidence laetrile/amygdalin treats cancer (citing the 2015 Cochrane review) and warns oral tablets release cyanide during digestion, risking liver and nerve damage, oxygen deprivation and death; it is banned in the USA and unavailable in the UK/Europe.
Guideline
FDA position
✓ Source
Never approved; promoted illegally as a cancer cure.
Clinical trial
Moertel 1982 (NEJM)
✓ Source
Clinical trial found laetrile ineffective against cancer.
RCT
Moertel et al. (NCI trial, NEJM) 1982
✓ PubMed
Landmark NCI-sponsored prospective clinical trial of 178 cancer patients given amygdalin plus 'metabolic therapy': NO substantive benefit in cure, improvement, stabilization, symptom relief, or survival. Several patients developed cyanide toxicity with blood cyanide approaching lethal range. Concluded amygdalin is a toxic drug ineffective as cancer treatment.
RCT
Moertel et al. (NCI Phase I, JAMA) 1981
✓ PubMed
NCI Phase I pharmacologic/toxicologic study in 6 advanced-cancer patients: IV amygdalin (4.5 g/m2/day) was largely excreted unchanged with no toxicity, but oral dosing (0.5 g three times daily) produced significant blood cyanide levels up to 2.1 ug/mL; one patient eating raw almonds developed transient cyanide toxicity with rising blood cyanide.
review
Spanoudaki 2023 (Int J Mol Sci)
✓ PubMed
Review of preclinical evidence across lung, breast, prostate, colorectal, cervical and GI cancers concluding current evidence cannot support amygdalin supplement use because its cyano-moiety causes adverse cyanide effects.
Review
Barciszewski/Mthembu MDPI Int J Mol Sci 2023
✓ Full text
2023 comprehensive review concluding that amygdalin's purported anticancer activity is supported only by in vitro and animal data, while human/clinical evidence has failed to demonstrate efficacy and shows cyanide toxicity risk.
review
Barakat 2022 (Biomolecules)
✓ PubMed
Narrative review concluding amygdalin shows only preclinical/in-vitro anticancer signals and that orally released hydrogen cyanide makes it harmful, with unpredictable toxicity dependent on gut microbiota; not recommended for patients.
Observational
Cmorej 2022, Prehospital Emergency Care
✓ PubMed
A 72-year-old developed life-threatening cyanide intoxication after ingesting an amygdalin dietary supplement and was successfully treated with the antidote hydroxocobalamin.
Review
Dang et al. 2017
✓ PubMed
Case report documenting severe, life-threatening cyanide toxicity in a patient who self-administered oral amygdalin tablets for metastatic cancer; symptoms resolved with hydroxocobalamin, illustrating the persistent real-world poisoning hazard of amygdalin/laetrile supplements.
case series
Talay 2025 (Arch Argent Pediatr)
✓ PubMed
Retrospective PICU case series of 14 children (1-18 y) with cyanide intoxication after eating apricot/almond kernels; weakness/fatigue was the commonest presentation (n=7), 4 had lip cyanosis and 3 altered consciousness, with 4 requiring hydroxocobalamin antidote for metabolic acidosis; all survived.
animal study
Bouhrim 2025 (toxicity study)
✓ PubMed
Acute/subacute toxicity study of bitter apricot kernel aqueous extract in Swiss albino mice; acute LD50 >6000 mg/kg but 28-day dosing at 1000 mg/kg lowered hematocrit and raised urea/creatinine, indicating renal/hematologic effects.
case report
Lokan & Sayers-type pediatric report — Sauer 2015 (Wien Med Wochenschr)
✓ PubMed
Case report of a 4-year-old with metastatic ependymoma who developed severe cyanide encephalopathy and metabolic acidosis with markedly elevated serum cyanide after alternative-medicine treatment using amygdalin plus apricot kernels, recovering fully after sodium thiosulfate.