The Ordinary Multi-Peptide Serum for Hair Density review

Over the years, I've really done a number to my naturally wavy and thick hair. I used to be a professional performer, which had me pulling my hair back extremely tight and wearing wigs for hours, making my hairline feel raw most days. On top of the constant over-styling, I've gone back and forth between blonde and brunette and tend to apply immense heat — it's no wonder my locks have so much breakage and my scalp always feels so dry and itchy.

But it was only recently that I discovered just how much damage I've caused. I started to notice thinning and short pieces along my hairline, most noticeably on my right side. I needed a solution to my hair growth and dry skin dilemmas, and according to dermatologists, one could be found in the right scalp serum.

Why I tried The Ordinary Multi-Peptide Serum | Why I like The Ordinary Multi-Peptide Serum | What to consider | More The Ordinary products to shop | Why trust Shop TODAY

One Shop TODAY writer saw improvements in just months of using this serum.

Size: 2 oz. or 1 oz. | Key ingredients: Redensyl, caffeine, peptides | Best for: All hair types

My search for one brought me to The Ordinary and its cult-favorite Multi-Peptide Serum for Hair Density. There’s a ton of buzz around the popular product, with many reviewers raving about it on TikTok (the #theordinaryhairserum hashtag currently has videos with millions of views on the platform). The serum is also a winner of Shop TODAY’s Beauty Awards — it earned a spot as the best hair serum for thinning hair, targeting hair loss.

I’m already a huge fan of the brand, having seen good results from its skin care products in the past, so I was excited to try the hair treatment and see what the hype is all about.

The multi-peptide serum is a leave-in treatment that is "designed to support the scalp and give you thicker, denser, fuller-looking hair," according to the brand. Its water-based formula contains three key peptide technologies — Redensyl, Procapil and Baicapil — which The Ordinary says can target stem cells and increase blood flow to the scalp. The product is also made to work on any hair type or texture.

For best results, the brand says to apply a few drops onto dry, clean hair at night, followed by massaging it into the scalp. I only wash my hair twice a week, so I was worried that applying a complete dropper full of the serum would leave it feeling and looking greasy. But it didn't! I found the formula to be extremely lightweight as well. Since I was hoping to see some improvement on my hairline, I also applied extra product to the areas where I noticed the most thinning.

I started using the hair serum consistently in June 2022. Within that time, I've noticed vast improvements to my scalp and hair. I no longer find myself itching my head throughout the day (unless I've gone too long without washing my hair), and the flaking is completely gone. Plus, my skin and strands went from feeling dry to hydrated and moisturized.

And while bad habits have been hard to break (I've been doing high-lift hair coloring), I still feel like the consistent use of this serum has started to repair my many years of hair abuse. My hairline looks fuller and there's new growth starting to appear. I even have family and friends commenting on how long my locks have gotten. Overall, I feel like my entire head of hair looks and, most importantly, feels healthier.

The brand recommends patch testing before using and to not use on broken skin. They also advise to avoid using it with other products that contain direct acids, vitamin C, salicylic acid and its Resveratrol 3% + Ferulic Acid 3% serum.

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Size: 1 oz. | Key ingredients: Glycolic acid, Lactic Acid, Salicylic Acid | Best for: Normal, combo and oily skin types

Size: 2 oz. or 1 oz. | Key ingredients: Hyaluronic acid, vitamin b5, ceramides | Best for: Dryness

Size: 1 oz. | Key ingredients: Copper peptides, Matrixyl, Glycerin | Best for: Dryness, fine lines, firmness

The Shop TODAY editors and writers search the internet to find the best products out there. We interview expert sources and use our own personal experiences with the product and brand to make shopping easier for our readers.

Shannon Garlin is an associate editor for Shop TODAY. She has been with the team over two years covering a wide range of topics, including product reviews, viral beauty and sales.

Shannon Garlin is an Associate Editor for Shop TODAY.