The Science of Hair Shine
Radiant hair is infinitely desirable, yet it can be so elusive. With Elixir Ultime, the scientists at Kérastase have harnessed the power of shine to infuse every strand with undeniable brilliance.
Two Types of Shine
Not all shine is created equal. When light hits the hair, it can create two types of reflection—specular and diffuse. Specular reflection is symmetrical, creating a bright, mirror-like shine. Diffuse reflection scatters light, weakening its intensity. How much of each type of reflection you see depends on the condition of the fiber. Rough surfaces produce more diffuse reflection, which is why damaged hair often appears dull.
The Golden Ratio
The ideal conditions for shine yield a high ratio of speculative to diffuse reflection, and Elixir Ultime is designed to encourage that high ratio by smoothing and nourishing the fibres instantly.
Speculative Reflection / Diffuse Reflection = Overall Shine

Enemies of Shine
Dirt
Deposited on the hair in the form of dust or product residue, dirt disrupts the hair’s ability to reflect light, causing it to appear dull and matte.
Sebum
Natural oils from the scalp can seep onto the hair when it hasn't been cleansed, clouding the surface of the fibre and reducing the hair's capacity for intense shine.
Friends of Shine
Marula Oil
Extracted from seeds inside the hard kernel of fruit from the Marula tree, this precious oil has incredible moisturising and nourishing properties. It softens and smoothes the hair, promoting a high level of light reflection, which appears to the eye as intense shine.
Camellia Oil
Taken directly from the seeds of the Camellia oleifera flower, precious Camellia oil is widely revered for its nourishing qualities. Comprised largely of oleic acid, linoleic acid and vitamin E, its nutrients can smooth and calm any hair type, creating the ideal conditions for high shine