The Ordinary Hair Serum Review: A Doctor Weighs In

If you’ve been online or on TikTok lately, you’ve probably seen The Ordinary products on someone’s bathroom shelf. They’re sleek, minimalist, and super affordable.

Specifically, the brand’s Multi-Peptide Serum for Hair Density has been making waves. With claims that it supports thicker, fuller hair, it’s no surprise this scalp serum has gained traction on social media and skin care forums alike.

But does it actually work? This review of The Ordinary Multi-Peptide Serum for Hair Density breaks down what’s inside, how it works, who it’s best for, and a dermatologist gives his thoughts about whether it’s a hair care product that actually helps with hair thinning.

The Ordinary Multi-Peptide Hair Serum for Hair Density is a lightweight, water-based formula designed to help with thicker hair and overall density. It comes in a 60 milliliter (mL) dropper bottle and is applied directly to the scalp, typically at night.

The serum combines several ingredients that are often used in hair-support products, including peptides, caffeine, and plant extracts, and it aims to improve the look and feel of fuller hair.

Deciem, The Ordinary’s parent company, also says the serum is vegan, cruelty-free, and free of harsh additives, fragrances, and alcohols, so it should be gentle enough for people with sensitive skin or minimalistic routines.

Unlike traditional treatments like minoxidil or finasteride, this scalp serum isn’t FDA-approved for hair loss.

The serum’s formula leans on multi-peptide technology, which is basically a blend of signaling proteins that can help encourage hair follicles to behave like they did when they were healthier and more productive.

The key ingredients include the following:

• Redensyl^™: A patented complex believed to decrease stem cell death and initiate the anagen (growth) phase

• Baicapil^™ and Procapil^™: Botanical-based ingredients that may help improve hair anchoring and follicle vitality

• High-solubility caffeine: Meant to help counteract the effects of DHT (a hormone that contributes to androgenetic alopecia, or male pattern hair loss), according to the brand

• Capixyl^™ and AnaGain^™: Peptides meant to help reduce hair fall and improve the hair growth cycle

• Hyaluronic acid: Meant to help improve dry scalp, add hydration, and support healthier hair over time

To use it, the brand says to apply a few drops directly to the scalp each night and massage in gently. It’s meant to be a leave-in, so there’s no need to rinse it out, and the brand says it’s safe to layer with other scalp-friendly products.

Below, you’ll find an honest review of The Ordinary Hair Serum from board-certified dermatologist Knox Beasley, MD.

Product Type: Hair regrowth serum

Key Ingredients: Peptides, caffeine, and hyaluronic acid

Cost:  $23 per 60mL bottle

Purpose: Claims to use patented ingredients and peptides to help with fuller, thicker hair

• Efficacy: ★
  “This serum contains caffeine, which has some limited data treating hair loss, but there is minimal evidence the other ingredients would have much benefit,” Dr. Beasley says.

• Side effects: ★★★★
  “This could potentially cause some irritation and itching of the scalp, so I would do a test spot first,” he notes.

• Ease of use: ★★★★
  “This is applied once daily at bedtime,” Dr. Beasley notes, which makes it relatively easy to use.

The bottom line? “There is limited data that this would be effective at treating hair loss,” Dr. Beasley says.

Pros

• Lightweight, non-greasy formula

• Fragrance-free and alcohol-free

• Affordable compared to some other treatments

• Easy to apply

• Safe for most hair types

• Can be used alongside other treatments like minoxidil

Cons

• Not FDA-approved to treat hair loss

• Results can take several months to show

• Doesn’t work for everyone

• Dropper bottle can be a bit messy

• May not help with hormonal hair loss

• Limited peer-reviewed research on the entire formula

Here are some answers to some FAQs about The Ordinary Hair Serum:

Does The Ordinary Hair Serum actually regrow hair?

Not exactly. It’s not a drug like minoxidil or finasteride, so it’s not proven to regrow hair. But some users report fuller-looking hair and less shedding over time.

If you’re dealing with pattern hair loss, it may help support your scalp, but there is no data to suggest it will reverse the condition. Instead, you should reach out to a doctor for actual treatment. Hims can connect you to a provider who can recommend a solution based on your needs.

How long does it take to see results?

Patience is key. Most users see changes within a few months, but results vary depending on the type of hair thinning you're experiencing. Like many topical products, consistency is important.

Can I use The Ordinary Hair Serum with minoxidil?

Yes, and many people do. Because this serum is lightweight and non-irritating, it can be layered into a routine that includes minoxidil. Just make sure to space them out (for example, use one in the morning and one at night).

Is The Ordinary Hair Serum similar to Vegamour?

Kind of. Like Vegamour GRO Serum, The Ordinary’s formula focuses on botanical extracts and peptides, not FDA-approved ingredients. Both aim to support healthier-looking hair without the side effects of stronger medications. The main difference is price: The Ordinary comes in at just over $20, while Vegamour costs closer to $60 for a similar volume.

How much does The Ordinary Hair Serum cost?

You’ll typically find it for around $17 to $23 for a 60mL bottle. That’s enough to last about one to two months with nightly use.

Most people report tolerating this serum well, especially because it’s fragrance-free and doesn’t include common irritants. Some reviewers on the site report mild itching or tingling on the scalp during the first few uses, but these effects usually fade over time.

As of now, there are no large-scale clinical trials published in peer-reviewed medical journals about this specific product, so most of the evidence is anecdotal or based on the known actions of its individual ingredients.

If you’re unsure about The Ordinary Hair Serum, check out these alternatives for hair loss or thinning:

Minoxidil

Minoxidil (like the 5% foam or solution offered by Hims) is FDA-approved to treat hair loss. It works by increasing blood flow to the scalp and stimulating follicles. If you're looking for results backed by decades of research, this is a stronger option than The Ordinary serum, especially for male pattern hair loss.

Finasteride

Finasteride is a prescription medication that blocks DHT at the hormonal level, helping to prevent follicle shrinkage. Hims offers access to a provider who can prescribe both pill and topical options.

• The Ordinary Hair Serum is a cosmetic product that aims to support scalp and follicle health using peptides, caffeine, and botanical extracts.

• It’s relatively easy to use and affordable, but it’s not FDA-approved for treating hair loss, and there’s limited data to back its efficacy.

• If you’re dealing with mild thinning, this serum could be a helpful part of your routine — especially when paired with proven treatments like minoxidil.

• More stubborn or hormone-related hair loss? A solution like minoxidil or finasteride may give you better long-term results.