Vitamin B17, Amygdalin or Laetrile: Truth and Facts

There are three names used interchangeably — Vitamin B17, Laetrile, and Amygdalin — however, they are not the same compound. Understanding the differences matters when choosing a supplement.

Cyanogenic glycosides are a large group of secondary metabolites widely distributed in the plant kingdom, including many plants commonly consumed by humans. Amygdalin is the naturally occurring compound; Laetrile is a patented, semi-synthetic derivative; and "Vitamin B17" is a popular name applied loosely to both.

The hero image above illustrates the anatomy of a drupe fruit. Amygdalin is concentrated in the seed (kernel) housed inside the endocarp — the inner woody stone — of apricot fruits. This is why only certain seeds yield meaningful amygdalin concentrations.

What is Amygdalin?

Amygdalin is a naturally occurring cyanogenic glycoside found in over 1,200 plant species, notably in seeds of fruits in the Rosaceae family such as bitter almonds, apricots, and plums. Each molecule of amygdalin contains one unit of hydrogen cyanide, one unit of benzaldehyde, and two units of glucose (sugar) tightly locked together.

Amygdalin — Natural (C₂₀H₂₇NO₁₁)

Property	Value
CAS Reg. No.	29883-15-6
Empirical Formula	C20H27NO11
Molar Mass	457.43 g/mol
Appearance	White to beige powder
Melting Point	223–226 ºC
Water Solubility	50 g/L
Glucose Units	Two (diglucoside)

Despite its widespread occurrence in nature, amygdalin is erroneously confused with Laetrile, and both are sometimes called "Vitamin B17." In recent years, researchers have conducted several studies to improve understanding of this compound. Some people taking amygdalin are more prone to developing cyanide sensitivity while others are not — the human body's metabolism is complex and several factors influence these dynamics, including diet, age, and other supplements.

What is Laetrile?

Laetrile, patented in the United States in 1961, is a semi-synthetic molecule sharing part of the amygdalin structure. It is a derivative of amygdalin formed by the hydrolytic removal of one glycoside group from the parent compound, meaning each molecule of Laetrile contains one unit of hydrogen cyanide, one unit of benzaldehyde, and only one unit of glucose.

Dr. Krebs Jr. extracted certain glycosides from plants containing nitrilosides and applied for a patent for the process of producing a metabolite form of these glycosides for clinical use. He named it "Laetrile" (Laevo-mandelonitrile-beta-glucuronoside). The patented version is structurally different from naturally extracted amygdalin.

Laetrile — Semi-synthetic (C₁₄H₁₅NO₇)

Property	Value
CAS Reg. No.	1332-94-1
Empirical Formula	C14H15NO7
Molar Mass	309.27 g/mol
Appearance	White powder
Melting Point	214–216 ºC
Water Solubility	83 g/L
Glucose Units	One (monoglucoside)

Amygdalin Content in Fruit Seeds

Multiple fruit kernels contain amygdalin, but concentrations vary significantly. The seed inside the apricot endocarp (inner woody stone) is the primary source for supplement production. The data below, compiled from published research, shows amygdalin content per gram of seed across common fruit species.

While green plum seeds show a higher amygdalin concentration in some studies, bitter apricot kernels are the industry standard source for supplement production due to their consistent yield, established extraction protocols, and depth of research behind them.

Why the Three Names Are Used Interchangeably

The term "Vitamin B17" was coined by to describe the nitriloside class of compounds — a collective name that includes both amygdalin and laetrile. Because neither is officially recognized as a vitamin by regulatory bodies, the "B17" designation is a common name rather than a scientific classification.

When shopping for supplements, always look for products that specify amygdalin extracted from apricot seeds and provide HPLC purity documentation. TJ Supply's Novodalin products meet ≥98% purity by HPLC and are produced using low-temperature extraction processology.