sade087

If full-strength, inexpensive shampoos are harsh on hair, stripping off natural oils and leaving the hair without protection so that it can lose moisture and other vital components, then is the only solution to buy shampoos with mild detergents? What if they're all too expensive or smell bad? Can there be a compromise in a market in which vilifying ingredients and marketing the more-expensive alternative is lucrative and not necessarily beneficial to the customer? ©Science-y Hair Blog 2013 As I tried to show in this post , yes and no. If a “mild” detergent is highly concentrated in a shampoo, it will still be harsh (cause the hair to swell and remove too much oil). It’s the same with hot peppers, a lot of red chilies (pretty hot) are going to make your eyes water as much as a little Serrano (super-hot). ©Science-y Hair Blog 2013 Yes, I know - some people don't use shampoo at all and it's much better if you shampoo every other day or less often. But some of us need to remove...

I've examined a number of shampoos (those that I had, I did not buy any for this project) to test the notion that certain detergents (surfactants) are harsh and others are not. I did this through examination of hairs in the shampoo under a transmitted light microscope, in comparison to those hairs dry or in distilled water. When hair is well-saturated with water, it swells. But different hair swells different amounts. Hair treated with coconut oil doesn't swell as much. Fine hair doesn't swell as much. Undamaged hair without many porosities swells less than damaged hair. I measured some hairs, dry vs. wet and found quite a difference in the amount of swelling in water. Pufferfish, all puffed up. Pufferfish, not yet puffed up. Never the less, water alone makes hair swell and in so doing, causes the normally-flat cuticle to lift and this creates porosities for things to leak out or diffuse in. Wetting hair alone has a "damaging" quality. Think of a pufferfish to get...