What is hair serum?

It's a common misconception that hair serum will weigh down naturally fine hair. Instead, it all depends on which serum you use and in what quantity. Hair serum has a plethora of fans who claim that it has revolutionised the appearance of their hair, while other people aren't quite sure where and how it fits into their haircare routines. We take a closer look at what exactly hair serum is, how it works, whether it's right for you and, if so, how to get the most out of it.

What is hair serum used for?

Hair serum is a liquid-based treatment usually formulated using silicones that provide a protective layer over the hair fibre, assisting in smoothing frizz. This smooth layer then reflects the light, which is how serum gives your hair a shiny, not greasy, finish. For some people, this removes the need to use straighteners to smooth out the hair afterwards: great for cutting styling time in half and saving your hair from heat damage.

It's not common knowledge, but hair serum isn't just used to tame frizz. The right serum for your hair type can address multiple concerns, from smoothing the hair, adding shine and detangling to repairing damage and protecting from pollution. Hair serum is also a good way to hide split ends in-between visits to the hairdresser.

How to apply hair serum?

Hair serum is normally applied onto wet or towel-dried hair after shampooing and conditioning, although some can also be applied onto dry hair.  The Absolut Repair Molecular Rinse-off Serum is used on wet hair after shampooing, apply a few pumps onto the palm and apply from root to tip onto the hair. 

Because serum provides a protective coat over the hair, it can prevent damage when applied before using heated tools such as hair straighteners. The SteamPod Smoothing Treatment is a thermo-protective serum that protects hair from heat and extreme humidity conditions.

Your questions answered

We answer some of the most common questions that our professional haircare experts get asked when it comes to hair serum.

Should I use hair serum if I have naturally fine hair?

It's a common misconception that hair serum will weigh down naturally fine hair. Instead, it all depends on which serum you use and in what quantity. A serum formulated to repair and strengthen hair, like the Absolut Repair Hair Serum, will actually give thicker, healthier-looking results. If your hair lacks volume, or quickly becomes greasy at the roots, focus your serum application on the lengths and tips, and only use a couple of drops.

If you're looking to actively thicken your hair, try the Serioxyl Denser Hair Serum from L'Oréal Professionnel, used in a three-month daily programme, to add density to the hair and achieve greater volume and thickness.

What's the best hair serum?

A with any haircare product, finding the best hair serum depends on your hair type and concerns. If you're unsure about which serum will give you the best results, ask your L'Oréal Professionnel hairdresser. They will be able to diagnose your hair and suggest the most suitable hair serum to include in your haircare routine.

When should I start using hair serum?

If you've noticed your hair looks dull and lacklustre, it tangles and breaks easily, if you suffer from frizz or flyaways, or are a regular user of heated tools to straighten or curl your hair, serum could be your haircare solution. Many also find that hair serum is a must when it comes to humid weather, vacations, or any situation where frizz and flyaways can be a particular pain.

What's the difference between a hair oil and hair serum?

Hair oil and serum may have similar textures, but are not the same. The former is designed to penetrate past the hair cuticles into the cortex of the fibre itself to restore the hair after damage such as post-colouring or after over-styling. The latter, as we have seen, is used as a styling tool to protect hair, increase shine and reduce frizz by providing a glossy and smoothing layer over the hair fibre.