How do shampoo and conditioner work?
In many ways, shampoo is simply a body wash, with slight modifications to improve it’s performance for your hair. The same basic principles that applied to soap apply to shampoo. The basic cleanser in shampoo is the same surfactant that is used in soap. Lathering agents, thickeners and other additives to adjust pH and add moisture and fragrance are added, but the basic shampoo is very similar to a body wash.
Amphoteric- can change their behavior based upon pH of the environment, often they are very gentle on the hair and eyes, making them good options for baby shampoos as well as for those with chemically treated or fine hairbetaines derivatives (cocamidopropyl betaine)
|Detergents||Lauryl sulfates- the main surfactant in most shampoos since a great lather is made, works in hard and soft water. Rinseable, but hard on hair.||sodium lauryl sulfate
triethanolamine lauryl sulfate
ammonium lauryl sulfate
|Laureth sulfates- Good lather, clean well and leave hair in better condition||sodium laureth sulfate
triethanolamine laureth sulfate
ammonium laureth sulfate
|Sarcosines- Great conditioners, but poor cleansers, usually used jointly with another detergent||lauryl sarcosine
sodium lauryl sarcosinate
|Sulfosuccinates- Great at removing oil, often found in oily hair shampoos||disodium oleamine sulfosuccinate
sodium dioctyl sulfosuccinate
|Foaming Agents||Introduce gas bubbles, creating foam. Lather is pleasant (I love it!) but doesn’t say anything about cleaning power. Oil decreases lather, so you’ll see less lather with dirtier hair.|
|Thickeners||It should be obvious what these do|
|Opacifiers||These make your shampoo look “pearly”|
|Conditioners||Again, obvious what these are. Likely to be found in more varieties and higher amounts in shampoos for dry hair||fatty alcohols
humectants (look at the cleanser post for a good list)
hydrolyzed animal protein
|Sequestering agents||These keep minerals and hard metals dissolved in the water. Without doing this, they would form a film on the hair.|
|pH adjusters||Most shampoos are more basic (higher pH) which can damage hair by causing the hair shaft to swell and break. Some shampoos have adjusted the pH to more neutral, which is better for the hair.|
Washing your hair too often can strip it of oils, leaving it dry and difficult to manage. As a result, conditioners were invented to help replace those oils, improving the hair’s condition leaving it silky and shiny. Back in the day, conditioners were made of things like wax and egg whites, today most conditioners are silicone. The amount of silicone in the conditioner and the amount left behind after rinsing will determine whether the formula is intended for those with fine limp hair (less silicone is left) or curly hair (more silicone is left).
Honestly, conditioners are just not as fun to write about as shampoos. We all know that conditioners will increase shine and flexibility, make our hair more manageable and help us with split ends. It turns out that it really does do all of this by smoothing down the hair’s cuticle (remember all of those Alberto VO5 ads?), and that by doing so a good conditioner can literally HEAL a split end! Well, a mild one, but still! It can happen!
There are a few specialized ingredients that you should know about, otherwise the composition of a conditioner is quite a bit like that of a shampoo, from what I can tell with my reading.
|Film Coating Agents||You want your conditioner to leave a film on your hair, really! They smooth down the cuticle and help to fill in gaps beween the cuticle scales. This also helps to dramatically improve shine.||polyvinylpyrrolidone (PVP)|
|Protein Conditioning Agents||Again, think of those Pantene and VO5 ads. Where the scale is missing, the cutex of the hair is exposed below. There is damage there, and the hair is very vulnerable to breakage. These proteins are broken up enough that they really can penetrate into the damaged areas and strengthen them. More penetrates as you leave on the conditioner longer. A 10% increase in strength can be seen (which means a lot of breakage can be prevented), but all benefits are washed away by your next shampoo!||Keratin
|Silicones||Creates a thin film similar to other ingredients, holding down the scale of the cuticle. However, silicones create a thinner film, and are less prone to creating limp hair.||dimethyl silicone|