From CeraVe’s retinol serum to L’Oréal’s bond-building range, TikTok has propelled many under-the-radar beauty products to instant fame. The latest one to steal the limelight? The Ordinary’s Multi-Peptide Serum For Hair Density. In fact, it looks like it’s one of the most googled hair products recently.

The lightweight serum is designed to transform hair, making it thicker, fuller, denser, and healthier, thanks to a megamix of clever ingredients, and it seems TikTokers can’t get enough of its hair-boosting properties. Hair thinning is something I have experienced for a while thanks to the hormonal condition polycystic ovary syndrome (PCOS), which causes diminished hair around the hairline and temples. I also straighten my hair daily, so I welcome anything that improves frazzled strands. Admittedly, hair-growth shampoos, conditioners, and treatments haven’t worked well for me, but on hearing so many excellent things about The Ordinary‘s serum, I had to try it.

The Ordinary Multi-Peptide Hair Density Serum, $21.70

What is in The Ordinary’s Multi-Peptide Hair Density Serum?

According to The Ordinary, the formula boasts a technology called REDENSYL complex. Don’t let the obscure name put you off, though. It contains peptides, which are said to repair and strengthen hair. Alongside this powerhouse ingredient, you’ll find caffeine, which the brand says makes the formula easily absorbed into the scalp, alongside castor oil, which has long been championed by trichologists and hair loss experts for stimulating hair growth and thickness when combined with regular scalp massage. There are also hair conditioners to increase softness and humectants (moisturizing ingredients) like glycine.

Although the product is labeled as a serum, the texture is actually much thinner, like water. But don’t underestimate it. It sinks into the scalp without a trace, so it doesn’t feel greasy or sticky in the hair.

How do you use The Ordinary’s Multi-Peptide Hair Density Serum?

The leave-in serum is recommended to be used once a day, applied to a clean, dry scalp, and ideally at nighttime before bed, when it’s said that skin and hair regenerate. As the product contains castor oil, I set aside a couple of moments after applying my evening skin care to really massage it into my roots in a bid to stimulate hair follicles. Overall, it was really quick and easy to use compared to hair growth products I’ve tried, such as hair masks (which need to be rinsed out) and hair oils (which can sometimes weigh down hair).

Does The Ordinary’s Multi-Peptide Hair Density Serum work?

Yes, and the before-and-after pictures are proof. While the instructions don’t state how long you should use the product, I noticed teeny tiny hairs begin to sprout from my roots after just two weeks. A whole month later, my sparse patches gave way to a crescendo of dark baby hairs which concealed my bald patches. Amazed, I scoured the internet for other reviews. Some people said that they noticed the best results after using more than one bottle, while others saw changes after just three weeks. All in all, you don’t need to search far and wide to read 5-star Sephora reviews across all ages and hair types.

Unfortunately, I didn’t notice much of a difference in my parting, which is also starting to thin out, but I put that down to scraping my hair back every day. That said, my right side in particular shows obvious growth and thickness, and when I brush my baby hairs, any sparse patches are totally concealed. While it worked well for me, some factors might stall hair growth, for example, hormonal issues and genetics. If you are concerned about hair thinning or it’s getting you down, it pays to visit your medical provider or a trusted hair expert or trichologist for further advice.

What are the best products and treatments for hair growth?

There’s no doubt The Ordinary’s Multi-Peptide Serum is a game-changer, but Dr. Nilofer Farjo of the Farjo Institute says that there are also some medicines that can help manage hair loss and hair density. “Finasteride in tablet form is probably the most effective medicine for strengthening hair and halting further loss,” she explains. “Another popular treatment is minoxidil, widely known as Rogaine, which is applied as a foam or lotion.” This can be bought over the counter at pharmacies as well as Amazon. The Farjo Institute’s Dr. Bessam Farjo adds that these are the only FDA or MHRA-approved medications to treat patterned hair loss. While some products may advertise hair growth, they are unlikely to be backed by as much scientific research as the above two treatments, but it’s all down to personal preference.

What about hair supplements? “The problem with supplements is that you could walk down the aisle of most chemists and find an array of supplements promising to help hair loss,” says Dr. Bessam. “But the truth is, this is an area of the market where unfortunately you might see a lot of overpromising and perhaps miss-selling.” Dr. Nilofer seconds this and adds: “There is a definite place for these non-prescription products as part of your hair-loss treatment regimen, as long as you appreciate it is more of a support role.” In other words, hair supplements alone won’t solve the issue but might make a great addition to leave-in hair treatments, such as The Ordinary’s. “Supplements are also a good option if hair loss is at a very early stage or the objective is to improve the quality of existing hairs,” continues Dr. Nilofer.

Looking back at the before-and-after pictures, it’s obvious that Multi-Peptide Density Serum is working for me, so much so that it has become a firm fixture in my evening beauty routine. If you’re interested in giving it a go, I’d suggest doing a quick patch test (as with all new topical products) before committing fully, to minimize any potential irritation.

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