Ximenic acid (C26:1, n-9) is a monounsaturated fatty acid with 26 carbon atoms and one double bond found on the 9th carbon atom from the end. It’s a very long chain fatty acid.
It has a melting point of 45.5˚C to 50.9˚C (113.9˚F to 123.6˚F), so it’s solid at room temperature. It will increase the viscosity of any liquid oils that contain it.
This fatty acid works as a moisturizer as well as an occlusive ingredient that can reduce transepidermal water loss (TEWL) from our skin.
It’s also known as cis-17-hexacosenoic acid.
It’s found in Ximenia seed oil, hence the common name of ximenic acid.