What it is
Myristic acid is a common straight-chain saturated fatty acid that is solid at room temperature and contributes to the structure and feel of emulsions. When partially neutralized with an alkali it forms fatty-acid soaps that act as surfactants and cleansing agents, while in creams it can help stabilize the oil and water phases and adjust texture. In sunscreens it is a formulation aid rather than a UV filter.
Safety & warnings
Myristic acid is widely used and generally well tolerated, though, like other long-chain saturated fatty acids, it is often cited as having comedogenic potential and may not suit those very prone to clogged pores in rich leave-on products. In soap-type cleansers it can be drying for some users if the formula is high in fatty-acid soaps.
Origin & sourcing
Myristic acid occurs naturally in many animal and plant fats and is notably abundant in nutmeg, palm, and coconut oils; cosmetic-grade material is typically obtained from these vegetable oils.
Questions everyone asks
What role does myristic acid play in a sunscreen?
It works as an emulsifier and texture agent, helping bind the oil and water phases and shaping how the product feels.
Is myristic acid comedogenic?
It is often rated as having some comedogenic potential, so very acne-prone users may prefer to monitor how rich leave-on products containing it feel.