Homosalate CAS 118-56-9

1. Physical and Chemical Properties

Homosalate is an organic ester formed from salicylic acid and 3,3,5-trimethylcyclohexanol. Unlike many UV filters that come as chalky powders, HMS is a liquid, which is a massive advantage for processing.

Formulator’s Note: Its oily nature gives it excellent spreadability, but it can feel “greasy” if used at maximum loads without lighter esters to balance the skin feel.

2. Applications: More Than Just UVB Protection

While categorized as a UVB filter, Homosalate is rarely used alone. Its applications are strategic:

• The Solubilizer: This is its primary superpower. Solid crystalline UV filters (like Avobenzone or Bemotrizinol) are notoriously hard to keep dissolved. If they recrystallize, the SPF drops. Homosalate acts as an effective solvent to keep these solids in solution, ensuring the product remains stable on the shelf.
• Broad Spectrum Sunscreens: It is almost always paired with UVA filters to create broad-spectrum protection.
• Water-Resistant Formulations: Because it is hydrophobic (water-repelling), it helps formulations resist washing off during swimming or sweating.
• Hair Care & Color Cosmetics: Used in sprays and foundations to provide incidental UV protection to hair and skin.

3. Safety and Regulatory Awareness

Homosalate is safe when used correctly, but it is currently under the regulatory microscope, which buyers must be aware of.

• Handling: As a raw material, it is an irritant. Workers should wear protective eyewear and gloves. Avoid inhalation of mists if the product is being sprayed during manufacturing.
• Regulatory Limits:
  • USA (FDA): Approved up to 15%.
  • EU: Recent updates have tightened restrictions due to potential endocrine concerns. Always check the latest EU Cosmetics Regulation amendments before formulating for the European market (current trends suggest lower maximum concentrations, often around 7.34% or 10% depending on the final product type).
• Skin Sensitivity: It is generally well-tolerated, but like all salicylates, it should be used with caution in products designed for hyper-sensitive skin.

4. Storage and Logistics

One of the benefits of Homosalate is its stability compared to other UV filters. However, proper storage is vital to prevent oxidation.

• Packaging: typically shipped in 200kg plastic drums or 1000kg IBC totes.
• Environment: Store in a cool, dry, well-ventilated area. Keep away from direct sunlight.
• Temperature: It does not freeze easily, but cold temperatures can increase viscosity, making pumping difficult. Room temperature (15°C – 25°C) is ideal.
• Shelf Life: High-quality HMS typically has a shelf life of 24 months if the drum seals remain intact.