We had a conversation with hair expert Daan Kneppers, who has been working in the hair styling profession for more than a decade. As co-founder of salon VAHQ, hairdresser and hair stylist for productions, fashion magazines and campaigns, Kneppers is daily concerned with that which grows on our heads: hair.

''As a hair stylist, I am always looking for new ways, methods and textures to create something beautiful. And that always starts with the basics: what is the material hair actually and how does it react?''

Can you tell us more about the anatomy of hair?

Hair begins at the hair root. The hair shaft grows from this tiny hair root, which is the actual hair itself. The hair shaft consists of a very thin layer of marrow in the middle, which is similar to what is found in our bones. Surrounding this marrow is the hair cortex. Beyond the cortex layer is the cuticle layer.

The cortex primarily consists of protein and moisture. There is more protein than moisture in the cortex, but damaged hair tends to lose moisture more rapidly.

Which hair types are there?

There are as many hair types as there are people. However, you can categorize them based on several aspects. For example, you have hair thickness and hair density. Then there's also the hair texture, so some hair is smooth, while some hair is rough. Smooth hair is shiny, while rough hair may appear dull.

Additionally, you have hard hair and soft hair. There's also porous hair or closed hair. For example, hair with a lot of shine has tightly closed hair cuticles. This means it's very closed hair, and moisture doesn't penetrate easily, making it less prone to getting wet quickly compared to very porous hair.

For instance, bleached hair is often porous and tends to be stiffer, absorbing water quickly and becoming wet faster. On the other hand, very closed hair is less porous and thus less prone to getting wet quickly, making it more closed and less porous. So, I can always express it a bit in two opposite expressions.

Each hair type then has a bit more of this and a bit more of that from all these variables. And that's how there are millions of types of hair.

''Basically, every hair type consists of protein and moisture''

How do you recognize your hair needs?

You can recognise this by doing two tests: the stretch test and the float test.

With the stretch test , you take one hair that is dry. You wrap it around your fingers, hold it tightly and then pull it. If it then immediately breaks without stretching, the hair could use extra moisture.

If you pull it and the hair bounces along but does not return, that could be a sign of damaged hair. This could be due to a colour treatment, for example, or it could be due to friction - it can have all sorts of causes. Then it is a good idea to start using hair care with extra protein.

If the hair bounces along and back, then you actually just have very healthy hair and your hair has a good balance of protein and moisture.

The second test you can do is the float test. This involves putting a hair in a glass of water. If the hair sinks, then the hair is porous and needs moisture. If it floats, then the hair cuticles are nicely closed and it is less likely to absorb water. The hair is then not porous and has a good moisture balance.

What is the function of a good shampoo?

Hair is a special material and therefore has special characteristics. One of these features is that it absorbs substances very well: it is a magnet for anything and everything.

A good shampoo is therefore essential. The main function of a shampoo is cleansing. Because all substances, including oil, grease, smell, things suspended in the air, are contained in the scales of the hair. So a shampoo cleans between the scales to remove these substances.

Additionally, a good shampoo also has conditioning ingredients. As mentioned earlier, hair is a magnet for all kinds of substances, including caring ingredients. If it were purely and solely soapy ingredients, for cleansing, you would be left with very stiff and hard hair.

That is why it is important that a shampoo also contains nourishing ingredients. To ensure that during that cleansing, you at least leave nourishment in the areas where cleansing takes place.

What is the function of a good conditioner?

A conditioner nourishes and repairs the hair and closes the cuticles you have just cleaned. This is why you always use the order shampoo and conditioner.

After cleansing with shampoo, the hair cuticles are nice and open. By applying conditioner afterwards, you add nutrition between the cuticles. A conditioner also has the ability to leave hair cuticles closed.

My tip is to comb through the hair while applying conditioner. With the combing motion, the hair cuticle goes down with you and you close those cuticles with it. That way, you actually comb the hair cuticles in the right direction a little extra.

When do you often see results from your new hair care?

It takes about six weeks before you can really evaluate a new hair care product properly. This is because there is often still build-up from the previous product. The six weeks actually provide a build-up of the new care. So each time after a cleansing and conditioning treatment, a little extra protein or moisture has been added to your hair.

Do you have any hair tips you would like to share?

''I would love it if everyone embraces their own unique hair type. Let's spread the beauty ideal all the way to everyone's unique features and celebrate more that we are all different!''