Hair Shampoos
As a well-known hair scientist has said, shampoos are simplicity out of complexity. You could hardly guess what a complicated mixture is contained in that thick, fragrant liquid that you pour into your hand.
Shampoos have to be developed for different types of hair - normal, dry, greasy, permed, bleached and so on. Every shampoo has to be tested, not only as a formulation that is to be stored for months in a bottle or tube and then sold, but also as a product that is to be used on human hair and scalp.
In the laboratory, the experimental formulation is thoroughly tested on cut lengths of human hair before production is considered. The shampoo under test is applied to the hair and rinsed off, and an experienced technician judges the amount of tangling that results. This is only the start. Complex computer-assisted technology assesses many aspects of the product's performance.
If all goes well, the shampoo is evaluated in 'real life' conditions, on the hair of clients in salons. This is an essential part of testing, because it is the only way to judge whether the new product is acceptable to consumers. Only when these tests are completed safely and satisfactorily does the shampoo go on the open market for us all to try. This process may involve many thousands of tests and may take many months or years.
The development of shampoos
The development of hair care products over the last few years has improved their quality enormously.
For many years, the main cleansing products - for hair as well as skin - were based on soap. But soaps have their disadvantages, especially in hard water. Soap will not lather well in hard water, and produces an unpleasant scum that cannot be rinsed away. If hair is washed with soap this scum deposits on the hair and leaves it looking dull and lifeless.
In modern shampoos soaps have been replaced by cleansers called surfactants. These lather well in all types of water and rinse off easily and completely. Most modern shampoos also contain some conditioning agents. The cleansing agents clean the hair and scalp, while conditioners make it easier to comb the hair while it is wet and give it volume without 'fly away' when it is dry.
Most people nowadays wash their hair more often than was usual even a few years ago. This has led to
a great development of very mild cleansing systems. In addition, conditioners have been 'tailored' to suit
different hair types, allowing users to match the level of conditioning to the requirements of the hair at that particular time.
There is no fundamental difference between the shampoos sold in salons and those sold in retail shops.
What is in a shampoo?
The ingredients in today's shampoos are all well known, thoroughly tested and officially approved. The skill and the science of the manufacturer is directed to developing products that best meet the needs of their users. Those needs extend to the care of all types of hair under all possible circumstances, including the hardness and temperature of water, and even abuse by the user!
A shampoo is a mixture of ingredients which can be classified according to the jobs that they do. In the European Union, all shampoos must carry a complete declaration of their ingredients on the packaging. The label doesn't always tell you why each ingredient is included, but you can often work it out for yourself.
Cleansing agents
The main reason why people use shampoos is to clean their hair. Grease (sebum) and dirt is removed from the hair and scalp by the surfactant system. The properties of the foam produced by the surfactants can be altered by the addition of what are known as 'lather boosters'.
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Conditioning agents
These condition the hair. Nearly all shampoos contain some conditioning agents. Some contain more than others do see.
Functional additives
These include ingredients that control the viscosity (thickness) of the shampoo. A shampoo that was too runny would be messy to apply, whereas one that was as thick as, say, toothpaste might be hard to spread over the hair.
Another kind of additive controls the pH of the shampoo. Usually shampoos are formulated to be slightly acidic, with a pH between 3.5 and 4.5.
Preservatives
A shampoo without preservatives would make a splendid breeding ground for germs of every kind. These could make the product 'go bad' or decompose, and they could present a considerable risk to health. Adding preservatives prevents problems like these.
Some of the preservatives you may see named on shampoo labels include sodium benzoate, parabens, DMDM hydantoin and tetrasodium EDTA. In spite of their rather alarming names, these are all safe, tested and approved ingredients.
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Aesthetic additives
These are ingredients which are added to make the shampoo pleasant to use. They include colors, perfumes and pearlescing agents.
Medically active ingredients
Some shampoos contain active ingredients to treat medical conditions. For example, certain shampoos contain zinc pyrithione for the treatment of dandruff. Some contain panthenol, which is important for hair growth and which improves the moisture content of hair.
Just occasionally it can happen that shampoo is swallowed, perhaps accidentally, perhaps by an inquisitive child. For this reason every one of these ingredients is assessed, both alone and when combined with others, to check that it will not cause any harm in those circumstances.
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