Methyl Ester Sulfonate (MES) is a bio-based anionic surfactant made by sulfonating methyl esters derived from renewable vegetable oils such as palm or palm-kernel oil. It is used as a primary or co-surfactant in laundry powders, detergent bars, liquid detergents and dishwashing liquids, where it delivers strong detergency, good foam and excellent tolerance to hard water.

How is MES made?

Vegetable oil is first converted into fatty acid methyl esters, typically in the C16 to C18 chain range. The methyl esters are reacted with sulfur trioxide (SO₃) in a falling-film sulfonation reactor, then neutralised with sodium hydroxide and bleached to give a stable, light-coloured product. A well-controlled process keeps the di-salt by-product low, which matters because di-salt is less surface-active than MES itself.

Properties of MES

  • Type: anionic surfactant (sodium alpha-sulfo fatty acid methyl ester).
  • Forms: paste, powder, flakes and needles, at different active matter levels.
  • Hard-water tolerance: keeps detergency and foam in hard water better than LAS.
  • Biodegradability: readily biodegradable.
  • Feedstock: renewable vegetable oil rather than petroleum.

Why MES is considered more sustainable

Because its feedstock is renewable rather than petrochemical, and because it is readily biodegradable, MES is widely regarded as a more environmentally responsible surfactant than petroleum-based alternatives such as LABSA. Its strong hard-water performance can also reduce the amount of builder a formula needs.

Benefits of MES in detergent formulations

  • High detergency on oily and particulate soil.
  • Consistent performance in hard water, which is common across much of India.
  • Good foam profile for powders, bars and liquids.
  • Mild on skin compared with many conventional anionic surfactants.
  • Can partly replace LABSA to improve a formula's sustainability profile without losing performance.

Where MES is used

MES is used in laundry powders and bars, liquid detergents, dishwashing liquids and industrial cleaning formulations, anywhere strong detergency and good hard-water tolerance are required. It is often blended with LABSA, and it is also an ingredient option for concentrated formats such as laundry pods.

MES vs LABSA

LABSA is petroleum-derived and must be neutralised before use; MES is bio-based, supplied as a ready-to-use salt, and holds up better in hard water. For a detailed comparison, read the difference between MES and LABSA, or see how LABSA compares with SLES.

Explore our flagship MESAPON® MES product page for full technical specifications and available grades.