Propylene glycol, also known as propane-1,2-diol, is a colorless, odorless, viscous liquid with a faintly sweet taste. It is a diol, meaning it has two alcohol groups, and is miscible with water and many other solvents. Propylene glycol is widely used in food, cosmetics, pharmaceuticals, and industrial applications.
Chemical Properties
- Chemical formula: CH3CH(OH)CH2OH
- Classified as a diol (glycol)
- Viscous and nearly odorless
Uses in Food and Pharmaceuticals
- Approved as safe for food use by the US FDA and EU with specific limits for different food categories
- Functions include anti-caking agent, emulsifier, humectant, flavor carrier, antioxidant, stabilizer, thickener, and texturizer
- Used in baked goods, dressings, beverages, desserts, and pharmaceutical formulations as a solvent and carrier
Uses in Cosmetics
- Used as a solvent and humectant in cosmetics to increase viscosity and limit dehydration of products and skin
- Enhances delivery of key ingredients into skin
- Dosage in cosmetics usually around 3% as humectant, rarely above 10% as solvent
Safety and Regulation
- Considered generally recognized as safe (GRAS) by the FDA
- Low toxicity with rare cases of allergic reactions or toxicity from excessive consumption
- Maximum safe daily intake set by European authorities at 25 mg/kg body weight
- Not classified as hazardous under typical usage conditions
Production and Environmental Impact
- Commonly produced by hydrolysis of propylene oxide
- Can be derived from petroleum or renewable sources
- Breaks down readily in water, with low toxicity to plants and animals
In summary, propylene glycol is a versatile, widely used chemical ingredient with a strong safety profile when used within regulated limits in food, cosmetics, and pharmaceuticals.
