Heneicosanoic Acid

Heneicosanoic acid (21:0) is a long-chain saturated fatty acid found in trace amounts in certain foods and synthesized in the human body. 

While not widely studied, it plays emerging roles in lipid metabolism, membrane structure, and cell signaling, with growing interest in its relevance to metabolic health and analytical research.

What is Heneicosanoic Acid?

Heneicosanoic acid, or henicosylic acid or 21:0, is a straight-chain saturated fatty acid with 21 carbon atoms. It has the chemical formula C₂₁H₄₂O₂ and is classified as a long-chain fatty acid. 

This compound naturally occurs in small amounts in foods like fish oils, dairy products, meats, and some fruits, and it is also produced within the human body.

In terms of structure, heneicosanoic acid is a solid at room temperature and has a carboxylic acid group on one end of its carbon chain. It is highly hydrophobic (repels water) and chemically stable. 

Although not as common as other fatty acids, it plays a role in lipid metabolism, cell membrane structure, lipid transport, and cell signaling. Research is still ongoing to better understand its specific biological functions.

When is Heneicosanoic Acid Measurement Relevant?

Heneicosanoic acid is primarily measured in research settings rather than routine clinical testing. Its relevance includes:

Lipid Metabolism Studies

Scientists measure it to understand fatty acid profiles in blood, tissues, and other biological samples.

Metabolic Disorders

Heneicosanoic acid is studied for its potential role in metabolic conditions such as obesity, diabetes, and cardiovascular disease.

Analytical Applications

It is commonly used as an analytical standard in gas chromatography to help identify and quantify other fatty acids.

Because it is still being researched, testing for heneicosanoic acid is not part of standard medical diagnostics.

What Do Altered Levels of Heneicosanoic Acid Mean (Research Context)?

Changes in heneicosanoic acid levels may signal shifts in lipid metabolism. Research has sometimes linked these changes to higher risk or severity of metabolic disturbances. 

However, these associations depend on the overall context, including other fatty acid levels, diet, health status, and environmental factors. As such, altered heneicosanoic acid alone does not confirm a diagnosis—it is part of a bigger biochemical picture.

What Does the Absence of Specific Studied Heneicosanoic Acid Variations Mean?

If heneicosanoic acid levels are not abnormal, it doesn’t necessarily indicate good or bad health on its own. 

Because it’s not widely used as a clinical marker, its absence or presence must be interpreted alongside other metabolic, genetic, and lifestyle factors. Current research emphasizes contextual interpretation rather than isolated findings.

Key Characteristics and Safety Notes

• Molecular Weight: 326.6 g/mol
• Melting Point: 74–76 °C
• Solubility: Practically insoluble in water; soluble in organic solvents
• Common Forms: Crystalline solid
• Biological Locations: Found in the cytoplasm, cell membranes, and adiposomes
• Toxicity & Safety: May cause mild skin, eye, or respiratory irritation. Use with care in laboratory settings.

Applications Beyond Biology

Beyond its role in human metabolism, heneicosanoic acid is used in manufacturing paints, foams, and lubricants, and serves as a surfactant in material processing. It also helps identify microorganisms through lipid profiling and supports fatty acid analysis in experimental research.