Disclosed is a stable hair treatment composition comprising aliphatic acid selected from heterosubstituted aliphatic acid unsaturated aliphatic acid and a mixture thereof a fatty acyl isethionate product which product comprises 40 to 80% of one or more fatty acyl isethionate salts by weight of the product and 15 to 50% of one or more free fatty acids and/or the salts of the free fatty acid by weight of the product and at least 30% of water by weight of the composition wherein the fatty acid is substantially different from the aliphatic acid.
