What are ceramides?
Ceramides are one of three* types of lipids (the 'sciencey' term for oil) found in the cuticle (J. Cosmet Sci., 56, 1-16, 2005). The IN is emphasised because the oil in the cuticle is different from the oil on the outer hair surface. The outer oil is sebum which is dfferent from the inner oil
Why is there an oil in the cuticle?
The cuticle is made up of multiple layers and the oil acts as a cement to keep the layers together. (See the diagram -click to enlarge it)
How do ceramides work in hair products?
The truth is ceramides are most useful in chemically damaged hair. This means relaxed or coloured hair. L'Oreal studied African American hair and in truth natural hair which is unprocessed doesn't really take up the product in the levels that relaxed hair does (International Journal of Cosmetic Science, 24, 1-12, 2002)
What they did:
1. Treat virgin, lye and no lye relaxed hair with ceramide
2. Wash the hair in ceramide free shampoo (i.e check how much ceramide binds and does not get washed off)
|Hair type||Initial amount after treatment with ceramide||Post-Shampoo amount of ceramide (i.e what really sticks on)|
|Natural (untreated)||367||66 (18%)|
|Lye Relaxed Hair (sodium hydroxide)||
|No-Lye Relaxed Hair (guanidine)||829||441 (53%)|
Natural hair initially takes up very little of the artificially added ceramide and then drops off more than 80% of it showing that the ceramide is not well bound to the hair (i.e not required). Relaxed hair on the other hand benefits from ceramides and further results in the paper specifically show that for no-lye relaxed hair, there is an increase in breakage resistance (no they did not compare it to natural hair or lye relaxed hair)
Why does relaxed hair take up so much more?
Feel free to read the relaxing science post. Here I explain that relaxers dissolve hair oils both internal and external (go here).
1. Shampoo dissolves oil too so can natural hair be affected by this? I guess the easiest comparison I can make is if you have a dirty oven, do you think an oven cleaner with sodium hydroxide would perform in the same way as shampoo. On the grand scale, shampoo has nothing on dishwashing liquid and both of those have nothing in comparison to sodium hydroxide. Yes washing hair even in plain water will affect it BUT and it is a huge BUT the damage rate is nowhere close to chemical treatment (i.e relaxing or bleaching).
2. Do ceramides occur naturally? Yes they do, wheat germ being a common source. The synthetic form of ceramide is highly concentrated and therefore useful for giving hair a high dose. It is also designed to mimic the naturally occuring ceramide in hair which is different from that found in skin and plant sources.
3. What is the best way to use ceramides? In a leave in product
4. Which is better ceramide or protein conditioners? They are different products. Ceramides are meant to replenish the internal cuticle oil, hydrolysed protein patches up the cuticle surface.
*Incase you are wondering the other two oils are 18 methyl eicosanoic acid or 18 MEA and Cholesterol