Peter Thomas Roth Peptide 21 Serum.

Serums

About this product

A thick peptide-based serum designed to hydrate and improve skin radiance, applied before moisturizers.

Full ingredients

Water/Aqua/Eau, Glycerin, Rosa Centifolia Flower Water, Isopropyl Myristate, Squalane, Mannitol, Butylene Glycol, Natto Gum, Tripeptide-10 Citrulline, Acetyl Octapeptide-3, Palmitoyl Hexapeptide-12, Acetyl Tetrapeptide-11, Acetyl Hexapeptide-8, Acetyl Hexapeptide-1, Palmitoyl Oligopeptide, Acetyl Tetrapeptide-9, Acetyl Tetrapeptide-2, Tripeptide-1, Palmitoyl Tetrapeptide-7, Hexapeptide-11, Dipeptide Diaminobutyroyl Benzylamide Diacetate, Palmitoyl Tripeptide-5, Trifluoroacetyl Tripeptide-2, Palmitoyl Tripeptide-1, Sodium Polyglutamate, Sodium Hyaluronate, Tocopheryl Acetate, Retinyl Palmitate, Ascorbic Acid, Hydrolyzed Soy Protein, Hydrolyzed Wheat Protein, Lecithin, Pseudoalteromonas Ferment Extract, Acrylates Copolymer, Magnesium Chloride, Polysorbate 20, Dimethyl Isosorbide, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Leuconostoc/Radish Root Ferment Filtrate

Guru Score

72%

Mixed

Early verdict · Few reviews so far

What the gurus are saying

This serum's rich slip and setting finish divide expert opinion, with some praising its glow-boosting effect while others find the formula less innovative than the price suggests. The main caveat is texture: its thickness and silicones can cause peeling when layered under heavy or mineral sunscreens, so it pairs best with light, water-based sunscreen.

Synthesized from 2 expert reviews · most recent take January 2026

What they liked

Intensely hydrating texture
Silky slip, absorbs to a radiant finish
Ships internationally

What they flagged

Contains fragrance
Can pill under thick or mineral sunscreens

Best for

Mature skin

Type

SerumsDrops & dropper

Key actives

Vitamin C Retinoid Hyaluronic acidVitamin EPeptides Squalane

Formula notes

Fragrance-freeNo drying alcohol

Where to buy

Sephora → Ulta → Amazon → Google →

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What the gurus are saying.

Every take we've logged from this product's reviews across YouTube. Click any row to watch the moment they said it.

All takes Yay takes Nay takes Mixed takes Hide sponsored

Nipun Kapur

412k subs

~Yay

"I don't need it if you've seen my video the world's most expensive creams duped you know how much I raved about this product. I found the immediately from fantastic they ship from the UK to the US. This is literally like applying 10 hydrating serums in one."

No BS Beauty

89k subs

~Nay

"The closest one I could find was the Peter Thomas Roth Peptide 21 Serum, which actually is about the same price with not nearly as exciting ingredients in it and that one's got fragrance in it."

All 2 takes from No BS Beauty

Reviv Serums TelomErase 6-IN-1 Multi-Corrective Serum Review 😍 New Favorite Anti-Aging Peptide Serum

"The closest one I could find was the Peter Thomas Roth Peptide 21 Serum, which actually is about the same price with not nearly as exciting ingredients in it and that one's got fragrance in it."

Peter Thomas Roth Peptide Skinjection™ Amplified Wrinkle-Fix Refillable Serum Review, How to, Dupes

"It's a very thick serum. [...] You can apply this to your skin morning or evening after cleansing and toning and before other moisturizers. It's got a lot of slip to it, but once it soaks in, it sets to kind of a natural radiant finish. [...] I will say if you use this under a very thick sunscreen or some certain mineral sunscreens, if they're on the thick side, it can cause some peeling. I have a feeling it's from some of the silicones in here."

What the evidence says.

Independent of what the gurus think, this is what the published research supports about the main active ingredients here.

Retinoids

Retinoids are among the best studied ingredients in dermatology, with solid evidence for acne and for the fine lines and rough texture that come from sun exposure. Dryness and flaking in the first few weeks are common and usually settle.

Source: DermNet

Vitamin C

Topical vitamin C is an antioxidant with reasonable evidence for dullness and uneven tone. It breaks down in light and air, so how a product is formulated and packaged matters as much as the percentage on the front.

Source: DermNet

Humectants and emollients

Ingredients like these draw water into the surface layers and slow how fast it leaves. The evidence is for comfort, softness and hydration rather than for changing the structure of the skin.

Source: DermNet

Frequently asked.

What is Peter Thomas Roth Peptide 21 Serum?

A thick peptide-based serum designed to hydrate and improve skin radiance, applied before moisturizers.

Is Peter Thomas Roth Peptide 21 Serum worth it?

The gurus mostly approve it, but with enough reservations to keep it in the middle at a Guru Score of 72%.

What is Peter Thomas Roth Peptide 21 Serum's Guru Score?

Peter Thomas Roth Peptide 21 Serum holds a Guru Score of 72%. That is our read on how warmly the experts talk about it, based on the verdicts of 2 expert reviewers we have collected.