Why Your Hair Serum Isn’t Working: Common Mistakes and How to Fix Them

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Key Points

  • Common mistakes in application and product choice cause your hair serum to lose effectiveness.

  • If your hair looks greasy and weighed down after using serum, you’re probably using a serum that’s too heavy, using too much serum, applying too often, or experiencing product build-up.

  • If you’re still experiencing frizzy hair, flyaways, or dry hair, you probably need a heavier serum, to apply serum more often, or to use more product.

  • Ensure you’re using the right serum with the right technique to experience the full potential of your product.

Troubleshoot these common hair serum mistakes to fix your hair routine and start experiencing smooth, shiny, healthy, and nourished hair every day. Everyone needs to tailor their hair routine to their unique locks and goals. Find the right serum for you and experiment with different methods to find the perfect serum application for your hair.

Benefits of Hair Serums

Hair serums cater to every hair type out there. Using the right serum and technique allows you to reap all the benefits of this hair care product. Serum helps your hair in the following ways:

  • Hydrates and nourishes hair. Hair serum hydrates and nourishes your hair, making it look and feel healthier.

  • Protects hair from heat damage. Hair serum protects your hair from heat damage, such as from blow-drying or styling with hot tools.

  • Defies frizz. Hair serum defies frizz and makes your hair look smoother and more manageable.

  • Adds shine. Hair serum adds shine to your hair, making it look healthier and more vibrant.

  • Smoothes flyaways. Hair serum smooths flyaways and makes your hair look more polished.

If you don’t find the benefits you’re looking for or are dealing with the side effects of greasiness or build-up, visit these common mistakes and switch your routine.

Common Mistakes When Using Hair Serum

There’s a hair serum out there for every head of hair. If your hair serum isn’t giving you luxurious, shiny locks and an extra boost of moisture, it’s likely you’re making one of many common hair serum mistakes. Review the type of serum you’re using, how much you’re using, how often you use it, and your application technique. Fix some of these common issues to unlock the true potential of hair serum for you.

Using Too Much

Using too much serum is a common mistake that leaves your hair greasy and oversaturated. If your hair feels weighed down by your serum, it becomes lifeless and heavy. It’s difficult to style as it doesn’t hold.

Your hair is at its best when it has the right amount of nourishment, volume, and shininess. Using the right amount of serum allows you to add shininess and nourishment without greasing your hair. Start by adding just a little bit to your hair and gradually add more if you need it.

Not Using Enough

If you feel your hair is still dry, brittle, and frizzy, you’re probably not using enough hair serum. Hair serum tames your frizziness and moisturizes your locks. If you’re not seeing the benefits of your hair serum, try using a bit more product!

Wrong Serum

Using the wrong serum for your hair causes a combination of issues, including having an allergic reaction. Using a serum that’s too heavy for your hair weighs down your locks and might leave you looking greasy. It’s likely difficult to distribute through your hair, too, as the product is thick and clings onto your strands too quickly. Finer hair needs a serum that’s more liquid, as it distributes easier and more effectively.

If your serum is too light for your hair, your hair won’t drink up enough moisture. You may still experience frizziness, dryness, and a lack of heat protection. If your product is too light for your hair, use more serum during application and apply more frequently throughout the day, or switch to a thicker serum suited to your hair type.

Blondes shouldn’t use dark oil as it affects their golden shine. Even argan oil is too dark for blondes despite its golden color. Blondes should stick to clear serums and sometimes purple to balance out the brassiness of blonde.

Sleek serums for straight hair weigh down or flatten out curls. If your curls lose their bounciness or shape from your serum, you need a different serum! Look for a specific serum for curly hair.


How you apply your serum is just as important as the serum you choose. If you apply too much serum to your tips, they become weighed down and greasy. Applying serum to your roots often makes your hair look greasy and dirty. It weighs down your hair and makes you look like you need a wash.

For Dry Hair Application

Applying serum to your hair when it’s dry often makes it difficult to distribute. You may have stringy-looking strands or patches of greasiness that are easy to spot amongst the dry hair that doesn’t have enough serum. However, dry or frizzy hair benefits from an extra application throughout the day. If you need an extra boost of shine, heat protection, or frizz ease, apply an extra dose of serum sparingly to dry hair.

When you apply serum to dry hair, be shy about the amount of serum. It’s easy to apply too much. Put a drop into your palm and rub your hands together to warm the serum. Carefully rub your hands on your tips, then work your way up the hair shaft to slowly distribute more and more serum.

For Damp Hair Application

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It’s best to apply hair serum to damp hair — not soaking wet, but not dry. After you wash or co-wash, dry your hair a bit with a microfiber towel. Put a pea-sized amount of serum in your palm, rub your hands together to warm it, and start distributing it into your hair, starting at the tips. Slowly work your way up the shaft.

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If there’s leftover serum on your hands and you don’t have greasy hair, spread a light amount to your roots. Comb your hair with your fingers or a wide-tooth comb to distribute the product; wait a few minutes for the serum to soak in, then style as you wish.


It’s key to use your hair serum enough without overdoing it. There’s no golden rule for how often to apply serum; it depends on your unique head of hair. Experiment to see what works best for you. If you apply serum several times a day but experience greasiness and weighed-down locks, try applying it less. If you apply it once a day or less, but you still have frizziness or flyaways, apply it more throughout the day.

In most cases, it’s best to use hair serum once a day. You may need an extra application throughout the day if you have coarse, frizzy, or dry hair. Apply serum to your hair a few minutes before you heat style. Use a bit if you have flyaways or frizz throughout the day. Want an extra touch of shine and smoothness? Apply more serum!

Find the sweet spot of how often to apply your serum. Too little leaves you dry and frizzy, but too much leaves you greasy and weighed down.

Allowing Build-Up

If you experience a greasy look, dry or brittle hair, a lack of volume, little to no shine, and difficulty styling, you probably have product build-up. Many products, including hair serum, cause product build-up. It’s no big deal — it’s even expected — and it’s easy to tackle.

Use a clarifying shampoo once a week to deep-cleanse your hair and get rid of build-up. For an even deeper clean or a household fix, mix two parts baking soda and one part water to create a paste. Apply it to the lengths of your hair, let it sit for 15 minutes, then shampoo and condition it like normal.

According to board-certified dermatologist and the co-founder of CompleteSkinMD in NYC, Dr. Julie Karen, “Just like we exfoliate the skin on our face, introducing exfoliation to our scalp is an important tool in controlling and ridding the scalp of build-up… Using a scalp brush when shampooing will allow you to gently physically exfoliate the build-up away from the scalp so that the shampoo can then wash it out of your hair… You can also use your fingers to massage the scalp with your shampoo to try and physically remove the build-up, but be sure to use your finger pads instead of your nails.”

If you have excess build-up or prefer to avoid it, ensure your serum doesn’t have silicones or other non-water-soluble ingredients. If ingredients aren’t water-soluble, they stay on your hair even when you shampoo and condition.

Exclusive Use

Hair serum alone isn’t an entire hair care routine. If you rely on your serum to make your hair look luxurious and wonder why it’s lackluster, dry, or lacking shape, incorporate more products into your routine. There’s no need to go over the top and spend two hours using seven products in your hair. However, simply washing and adding a drop of serum won’t give you runway hair.

Add a mousse for more volume, add gel for more hold in your curls, blow dry for a sleeker look, or scrunch your hair for more shape in your waves. Hair serum is an important step for nourishment, protection, and appearance, but don’t rely solely on your serum!

Top Hair Serums

There are hair serums for volume, frizziness, growth, protection, hydration, and more. Decide what your hair needs the most and try some of these top hair serums for gorgeous hair.

No. 9 Bond Protector Nourishing Hair Serum
$30.00 ($10.00 / Fl Oz)

by Olaplex 

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03/07/2024 09:10 pm GMT

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Top Overall: Olaplex No. 9 Bond Protector Nourishing Hair Serum

Protect your hair from environmental damage by sealing the cuticle with Olaplex No. 9 Bond Protector Nourishing Hair Serum. This serum is rich in antioxidants to go beyond your cuticle and bond with your inner hair layer. It deeply nourishes your hair for increased health and leaves you looking silky smooth! Enjoy a soft, daily shine with this industry-favorite hair serum.

Hair Growth Serum for Thinning Hair
$15.98 ($7.99 / Fl Oz)

by The Ordinary

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03/08/2024 08:37 am GMT

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Top for Growth: The Ordinary Multipeptide Serum

Improve the health and density of your hair with an impressive hair growth serum — The Ordinary Multipeptide Serum. This serum has a beautiful combination of caffeine to stimulate the scalp, biotin to provide vitamins for hair growth, and peptides to improve the health of your scalp. Each of these serum ingredients works together to nourish your scalp and grow thicker, healthier hair. Plus, it improves the health of your scalp and hair!

Super Skinny Serum
$28.50 ($5.59 / Fl Oz)

by Paul Mitchell 

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03/07/2024 07:40 pm GMT

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Top for Frizziness: Paul Mitchell Super Skinny Serum

Cut your drying time and resist humidity-induced frizz with this blow-drying primer. Paul Mitchell Super Skinny Serum is here to help you tame flyaways, prevent frizz, and add a silky smooth finish to your hair. It’s perfect for all hair types.

Elle named Paul Mitchell Super Skinny Serum the best overall hair serum in August 2023 — suitable for everyone!

Hairdresser’s Invisible Oil
$31.34 ($9.22 / Fl Oz)

by Bumble and Bumble 

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03/08/2024 03:07 pm GMT

Top for Hydration: Bumble and Bumble Hairdresser’s Invisible Oil

Whether your hair is curly, straight, fine, or coarse, this oil is sure to absorb beautifully into your locks. Bumble and Bumble Hairdresser’s Invisible Oil is versatile and adds moisture to your dry or damaged hair. A harmonious blend of six oils and two extracts tames flyaways, controls frizz, and leaves you with a shiny finish.

Scalp Serum | Revitalize and Detoxify
$48.00 ($48.00 / Fl Oz)


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03/08/2024 09:02 am GMT

Top for Scalp Health: Divi Scalp Treatment

If you’re experiencing hair loss or scalp issues, try the Divi Scalp Treatment to soothe your scalp. This serum increases circulation to your scalp to help it heal and promote hair growth. It also prevents build-up on your hair to keep it healthy and light, preventing more hair loss. Copper Tripeptide 1, tea tree oil, rosemary leaf extract, caffeine, eucalyptus oil, peppermint oil, and green tea extract work together to invigorate your scalp, stimulate hair growth, and help you regain confidence in your mane.

Red-headed woman tilting head to the side to apply hair serum.

Master Your Hair Serum

Although it takes some trial and error to find the right serum and routine for you, it’s well worth the effort. Experiment and stick to a routine for a while, giving your hair a chance to react. Make gradual changes to see what works better. Over time, you’ll discover exactly what your hair likes and dislikes. Enjoy the process of self-care and a killer hairstyle!

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