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Hair Serum: What Is It and How Do You Use It?

BY Alyssa Montemurro

As far as essential hair products go, you probably think you’re pretty well-stocked at this point. You shampoo and condition, apply a hair mask at least once a week, and use a heat-protecting leave-in treatment post-shower. What else is there to consider?

Hair serum spilling GIF

As it turns out, you may be missing out on one key product with major multitasking benefits — hair serum!

Packed with a potent concentration of key ingredients, hair serums can effectively smooth, soften, and protect the hair from environmental aggressors. This way, your hair stays sleek and shiny all day long.

Love the idea of a hair serum but aren’t sure how to work it into your haircare routine? Below, we’ve broken down all of the essential do’s and don’ts of using this all-in-one product so you can start making the most of your daily hair goals.

What Exactly Is Hair Serum?

Drops of hair serum

Not to be confused with hair oil, hair serum is a silicone-based styling product designed to coat the hair’s surface to help impart added shine, smoothness, hydration, and humidity and pollution protection.

Intended to be used on wet or dry hair, serums can act as both a pre-styling treatment and a finishing product. It’s perfect for wash days, in-between washes, on-the-go touch-ups, and stylist-free days.

While some serums get a bad rap for being too heavy and slick for fine, thin, or oily hair types, our specially engineered hair serum is 100% customizable. That means it’s suitable for a variety of hair types, from coarse hair to fine hair.

The deets: Function of Beauty’s hair serum is formulated with a mix of argan oil, jojoba oil, and sunflower oil. Besides that, it features a custom blend of synthetic and naturally derived ingredients, including vitamin E, depending on your favorite hair goals. Just like the other haircare products at Function of Beauty, our hair serum is paraben-free, sulfate-free, and doesn’t contain other unwanted ingredients. (Check out our “No” list because what’s in your products is just as important as what’s not in them.)

The key to getting the most out of your hair serum, however, is learning how to use it properly. That’s why we’ve put together some quick do’s and don’ts for you to follow below.

Do Use It for Hairstyling

Woman massaging her scalp

Whether you want to blow-dry or flat-iron your mane, a heat protectant is key to toning down hair damage. Hair serums that offer serious heat protection, like Function of Beauty’s custom hair serum, are your bestie when it comes to hairstyling.

In fact, our hair serum is proven to:

  • Reduce frizz by 70%
  • Increase shine by 26 times more than untreated hair
  • Improve detangling by 75%
  • Thermally protect hair from damage up to 400 degrees

Indeed, it’s the all-in-one styling product you need on your vanity ASAP.

Do Use It to Tame Unruly Frizz and Flyaways

One of the greatest benefits of using a hair serum is its ability to block out humidity and create a sleek, polished finish. Simply put, there’s no better product to use when you’re trying to create that perfect glass hair look.

Rather than just applying your serum to damp hair before heat styling, we suggest also using it in place of your hairspray (a frizz-fighting no-no) to help tame any unruly strands. 

Simply rub a small amount of serum through the palm of your hands. Then, using two fingers, gently apply it to the strands using a pressing motion anywhere you want a smoother hair texture.

Don’t Apply Serum to Your Roots

The idea of having super-shiny hair from root to tip may sound like a good idea in theory. But trust us when we say that, unlike a scalp treatment, you’ll want to avoid applying your serum directly on your roots or scalp. This holds especially true for those with naturally fine or oily hair, as even the most lightweight serums have the potential to weigh the hair down, cause product buildup, and make your roots look greasy.

For that reason, we always recommend applying your serum to the ends first and slowly working your way up to the mid-shafts. This will not only ensure that you don’t overload on the product, but that you’re also only applying it to the part of your hair that needs it most (aka your naturally drier ends).

Don’t Apply Your Serum Right Away

Person getting a bottle of hair serum

Unlike hair oils, hair serums tend to be a little thicker in consistency, which can make working them into your hair a bit more difficult for some.

Our tip? Don’t try applying your hair serum as soon as you dispense it. Instead, try warming up the product between your hands for a few seconds so that it has the chance to break down and liquify a bit, giving you a little more slip. This’ll not only help your serum perform better but also ensure a more seamless, even application.

Don’t Over-Apply

Bottles of hair serum

If you take one thing away from this post, let it be this: There is such a thing as using too much hair serum.

Whether your hair is long or short, thin or thick, there’s a fine line between looking perfectly polished and flat and greasy. That’s why it’s important to start with a small amount of serum and then gradually work in more only as needed.

When in doubt, start with the least number of pumps recommended for your hair type and then slowly build from there. Whatever you do, just remember: a little goes a long way.

Do Consider Your Hair Type and Hair Goals

Different hair types

Just like all hair isn’t made the same, all hair serum formulas aren’t made the same either. That’s the reason we’ve made sure ours is fully customizable according to your hair type — do you have curly hair or straight locks? — and hair goals.

But figuring out which hair goals you should choose when creating your formula can be a little bit intimidating — we have over 15 different ones to choose from after all. To help, we’ve highlighted a few options for you to consider below.

You want: smoothness and shine

Try the shine, anti-frizz, and hydrate hair goals. They work together to help enhance your hair’s luster, protect against frizz, and ensure that it stays soft and well-nourished.

You want: longer-lasting, more vibrant color 

Try the color protection and shine hair goals. Together, they help lock in your hair color to prevent dulling, fading, and other signs of damaged hair.

You want: stronger, healthier hair 

Try the strengthen, fix split ends, and deep-condition hair goals. This triple threat provides a fortifying, nourishing, and conditioning formula that promotes hair wellness from the inside out to help prevent split ends, damage, and breakage from occurring.

You want: soft, bouncy curls

Try the hydrate and curl definition hair goals. Both of them help keep your curls moisturized while giving them the added definition and smoothness they need to look their best.

The Best Hair Serum Is the One That Complements Your Locks

Hair serums may not be the magical elixir for thinning hair or hair loss, much less to promote hair growth. But it’s definitely the go-to frizzy hair treatment — and for when you double as your own stylist.

So, what’s the best hair serum for you? Easy — the one that matches your mane’s unique needs. Instead of one-size-fits-all drugstore formulations, Function of Beauty’s custom hair serum is personalized to your tresses.

Ready to make hair serum a part of your daily haircare routine? Start customizing your hair’s perfect formula now.