Capsaicin (Cayenne Pepper)

Capsaicin is the principal pungent alkaloid found in the fruit of Capsicum species, most notably in cayenne pepper. It is responsible for the characteristic “heat” of these peppers and is widely used in dietary supplements for its thermogenic, analgesic, and metabolic‑modulating properties.

• Molecular Formula: Capsaicin (IUPAC: (E)-N-(4-hydroxy-3-methoxy-benzyl)-8-methylnon-2-enamide) has the molecular formula C₁₈H₂₇NO₃.
• Molecular Weight: Molecular weight is 305.41 g mol⁻¹.
• Structure: The structure comprises a vanillyl (4-hydroxy-3-methoxyphenyl) group linked via an amide bond to a long-chain (9-carbon) unsaturated aliphatic chain (8-methyl-non-2-enamide).
• Polarity and Lipophilicity:
  • The phenolic hydroxyl and methoxy groups confer moderate polarity.
  • The extended hydrocarbon chain confers lipophilicity, allowing membrane diffusion and interaction with the hydrophobic pocket of TR-V1.
• Acid-Base Properties: Capsaicin is a weak acid (pKa ≈ 4.8).
• Lipophilicity and Absorption: Displays a log P of ≈3.4, indicating moderate lipophilicity, which facilitates oral absorption (≈70% bioavailability) and skin penetration.

• Natural Source: Capsaicin is most commonly extracted from dried mature fruits of Capsicum annuum (cayenne, jalapeño, and other hot peppers).
• Extraction Methods: Commercial production uses ethanol or super-critical CO₂ extraction to obtain a standardized capsaicinoid (≥90% capsaicin) concentrate.
• Synthetic Production: Some manufacturers synthesize capsaicin chemically from vanillin and 8-methyl-non-2-enoyl chloride, yielding a product chemically identical to the natural molecule.
• Quality Standards:
  • Quality-focused supplements adhere to USP-NF or ISO 22000 standards.
  • Employ batch-testing for capsaicinoid content, heavy-metal contamination, and microbial load.
• Preferred Sources: Certified organic, non-GMO, and pesticide-free sources are preferred for dietary supplements.
• Pharmaceutical Grade: Pharmaceutical-grade patches use pharmaceutical-grade (≥98% purity) capsaicin with stringent sterility and stability testing.