What is Hair Serum | Hair Care Advice | L'Oréal Professionnel UK

How to use hair serum: Key takeaways (TL;DR)

Hair serum is a liquid treatment for your hair. It provides a layer of protection over hair fibre, which can help smooth frizz or target other hair concerns.
Hair serum can be applied to wet or dry hair.
Different types of hair serum will suit different types of hair and target different concerns, like taming frizz or repairing damage.
L’Oréal Professionnel hair serums include serums aimed at protecting colour, restoring damaged hair, targeting thinning, and being gentle on sensitive scalps.

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.

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.

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.

We’ll cover:

What is hair serum used for?
Benefits of hair serum
What’s the difference between hair serums and oils?
What hair serum should I use?

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 is the biggest benefit of hair serum as it removes the need to use straighteners to smooth out the hair afterwards. This is great for cutting styling time in half and saving your hair from heat damage.

It's not common knowledge, but the benefits of hair serum extend beyond just taming 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 between visits to the hairdresser.

How to apply hair serum

If you’re wondering how to apply hair serum, you’ll be pleased to learn it’s pretty simple. 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.

Benefits of hair serum

There are several key benefits of hair serum that make it a worthwhile addition to your haircare routine. These include:

Controlling and taming frizz
Providing a shield against heat damage
Detangling knots
Adding a natural shine and gloss
Targeting specific hair and scalp concerns

Once you’re familiar with how to use hair serum, you’ll start seeing results from the first use. If humidity and frizz have been the bane of your hair, then hair serum could be the perfect antidote, with Medical News Today saying that hair serums work to “protect, improve and recover the hair fibres’ properties, including smoothness, elasticity, and strength”.

What’s the difference between hair serums and oils?

Hair oil and serum may have similar textures, but are not the same. Hair oil 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. It can also help re-invigorate dry and dull hair, locking in moisture post-wash and nourishing the hair.

Hair serum, as we have seen, is used as a styling tool to increase shine and reduce frizz by providing a glossy and smoothing layer over the hair fibre. It also offers a layer of protection against heat damage, which hair oil does not.

What hair serum should I use?

Different types of hair serum will suit different types of hair, with some benefits of hair serums specifically formulated to target common issues like thinning or damaged hair. If you are unsure as to which hair serum to use, the following table shows the L’Oréal Professionnel serums best suited to each need.

Hair type	Serum	Benefits
Coloured	Vitamino Color Spectrum Glass Shine Serum	Colour protection, anti-frizz, anti-humidity, heat protection, locks in shine for up to 72 hours ¹
Damaged	Absolut Repair Molecular Rinse-off serum for damaged hair	Reforming & rebuilding molecular structure² of hair, restores original strength³, elasticity and movement⁴.
Thinning	Serioxyl Advanced Denser hair serum for thinning hair	Multiplies the number of hairs with daily use, for denser hair.⁵
Sensitive	Scalp Advanced Intense soother Treatment for Anti-discomfort	Intensely and instantly calms and soothes scalp discomfort, without weighing down the fibre. Hair is instantly smooth and detangled.

Up to 72hr after application, instrumental test vs unwashed hair
Instrumental test after 15 applications of rinse-off serum
Instrumental test
Consumer perception, 64 participants
Clinical study with 79 women during 12 weeks.

Discover L’Oreal Professionnel hair serums

Whether it’s thinning, coloured, damaged, or frizzy hair you’re working with, L’Oréal Professionnel hair serums can help. Our hair serums are packed with a range of unique benefits, from fighting humidity to heat protection and nourishment.

Discover L’Oréal Professionnel hair serums

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 theAbsolut Repair Molecular 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?

As 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.

How often should I use hair serum?

There’s no set answer to how often to use hair serum, as this can vary depending on hair type and condition. Most hair serums work best when applied to damp hair, so we recommend using your chosen serum after your regular hair wash. To benefit from heat protection, use it every time you style or dry your hair.

What is hair serum?