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INGREDIENT GUIDE

What are Peptides?

Complete Guide & Best Products

Author

David, askINKEY Digital Skincare Advisor

Published

7th July, 2026

Time to read

7 min

Last updated

3rd September, 2026

Peptides are one of the most quietly powerful families of ingredients in skincare, and one of the most misunderstood. They're not a single ingredient with a single job. They're a category: short chains of amino acids that act as messengers inside your skin, telling it to produce more collagen, retain more moisture, firm up, and repair itself. They work at a cellular level, which is why the results are real but gradual, and why consistent use is everything.

Whether you're noticing the first signs of ageing, dealing with dehydration, or simply looking to maintain the skin (and lips) you already have, peptides belong in your routine. This guide covers exactly what they are, how they work, and which INKEY List formulas deliver them most effectively, starting from just £11.

What are they?

Short chains of amino acids that act as biological signals within the skin

What they do

Support collagen production, improve firmness and elasticity, hydrate, plump, and reduce the appearance of fine lines

Best for

All skin types - especially skin showing early signs of ageing, dehydration, or loss of firmness

Can we used with

Hyaluronic Acid, Vitamin C, Niacinamide, Retinol, SPF - peptides are exceptionally versatile

When to use

AM and/or PM - suitable for both

Our top pick

Hyaluronic Acid Serum - £12 | 30ml

Key Benefits at a Glance:

  • Support collagen synthesis for firmer, more elastic skin
  • Reduce the appearance of fine lines and wrinkles
  • Strengthen and support the skin's moisture barrier
  • Hydrate and plump at multiple depths
  • Clinically proven to improve lip volume, eye area, and overall skin tone
  • Suitable for all skin types, including sensitive skin and during pregnancy
Shop Peptide Collection

Peptides are short chains of amino acids, the same building blocks that make up the proteins in your skin. The most important of these proteins is collagen, which gives skin its structure, firmness, and bounce. As we age, our body produces less collagen, skin becomes thinner, less elastic, and fine lines begin to form.

This is where peptides come in. When applied topically, certain peptides act as signalling molecules. They communicate with your skin cells, essentially mimicking the signals that tell your body to produce more collagen, repair damage, or retain moisture. They don't add collagen directly (collagen molecules are too large to penetrate the skin). Instead, they trigger the biological processes that produce it from within.

Think of peptides as a message written in your skin's own language. Your skin reads it, and responds.

Why Peptides Are Different From Other Actives

Most skincare actives work by doing something dramatic to the skin: exfoliating, brightening, or accelerating cell turnover. Peptides work differently. They work with your skin's own biology, supporting and amplifying processes that already exist but slow down with age. This is why they're:

  • Extremely well-tolerated. No irritation, no purging, no downtime
  • Effective across all skin types. From sensitive to oily to mature
  • Versatile partners. They enhance the results of almost every other ingredient they're paired with
  • Cumulative in effect. Results build over consistent use, rather than appearing dramatically overnight

Not all peptides are the same. The term covers a wide range of molecules, each with a different mechanism and a different target in the skin. Here are the main types you'll find in INKEY List formulations:

Signal Peptides

These tell the skin to produce more collagen or elastin. Matrixyl 3000™, found in our Hyaluronic Acid Serum and Caffeine Eye Cream, is one of the most extensively researched signal peptide complexes in skincare. It contains Palmitoyl Tripeptide-1 and Palmitoyl Tetrapeptide-7, which work together to support collagen production and skin repair.

Carrier Peptides

These deliver trace minerals or other actives deep into the skin to support collagen synthesis and wound repair.

Enzyme-Inhibitor Peptides

These slow down the enzymes that break down collagen. Royal Epigen P5™, in our Peptide Moisturiser, works partly through this mechanism, delaying the degradation of skin cells and helping to even skin tone at the same time.

Growth Factor Peptides

Epitensive™ EGF (Epidermal Growth Factor), found in our 15% Vitamin C + EGF Serum, is a plant-derived signal peptide that communicates with skin cells to support renewal and regeneration, improving elasticity and supporting a firmer-looking complexion over time.

Structural / Volume Peptides

Tripeptide Complex, in our Tripeptide Plumping Lip Balm, works at the surface of the lips to boost volume and definition by supporting the skin's own structural mechanisms. This is how you get real plumping without tingle, irritation, or the swelling tricks used by traditional lip plumpers.

Lifting & Firming Peptides

Tetrapeptide Complex (Tetrapeptide-111), in our Bio-Active Ceramide Eye Cream, is a targeted complex developed specifically for the eye contour. It smooths the look of fine lines and works to visibly lift and firm the delicate skin around the eyes, where expression lines show first.

The Science Behind Peptides
Peptide TypeExample in INKEY ProductsPrimary Action
Signal PeptideMatrixyl 3000™ (Hyaluronic Acid Serum, Caffeine Eye Cream)Supports collagen production and skin repair.
Epigenetic PeptideRoyal Epigen P5™ (Peptide Moisturizer)Helps delay visible skin aging and improve the appearance of uneven skin tone.
Growth Factor PeptideEpitensive™ EGF (15% Vitamin C + EGF Serum)Supports skin cell renewal and elasticity.
Volume PeptideTripeptide Complex (Tripeptide Lip Balm)Helps boost the appearance of lip volume and definition.
Lifting PeptideTetrapeptide Complex (Bio-Active Ceramide Eye Cream)Smooths the look of fine lines and visibly lifts and firms the eye contour.
Barrier PeptideDiffuporine® / Acetyl Hexapeptide-37 (Peptide Moisturizer)Supports skin barrier function and helps maintain hydration.
Smart PeptideKollaren (Exosome Glow Serum)Helps support natural collagen production and skin renewal.

Firmer, More Elastic Skin

The most well-established benefit of peptides is their ability to support collagen synthesis. Collagen is the structural protein responsible for skin's firmness and bounce. When signal peptides like Matrixyl 3000™ communicate with fibroblasts (the skin cells that produce collagen), they help restore the skin's structural integrity, resulting in visibly firmer, more elastic skin over consistent use.

In our 4-week independent consumer study, 82% of users agreed their skin felt firmer, smoother and more elastic after using the Hyaluronic Acid Serum (which includes Matrixyl 3000™ Peptide alongside 2% Multi-Molecular Hyaluronic Acid).

Reduces the Appearance of Fine Lines and Wrinkles

Fine lines form where collagen has thinned and the skin has lost its structural support. By supporting collagen production from within, peptides address the root cause rather than just filling in the appearance of lines. This is why peptide-based products deliver results that improve over time, rather than simply offering a surface-level plumping effect.

Strengthens the Skin's Moisture Barrier

Certain peptides, including the barrier-supporting Acetyl Hexapeptide-37 in our Peptide Moisturiser, help reinforce the skin's natural moisture barrier. A stronger barrier means better hydration retention, less sensitivity, and more resilient skin. This is one reason peptides are particularly valuable for skin that's dehydrated, stressed, or showing the early signs of environmental damage.

Deep, Lasting Hydration

Unlike simple humectants that sit on the surface and draw in water, peptides that target barrier function help lock hydration into the skin's deeper layers. Combined with other hydrating actives like Hyaluronic Acid, peptides create a multi-layer hydration system that delivers both immediate and long-term results.

Brightens and Evens Skin Tone

Royal Epigen P5™, the hero peptide in our Peptide Moisturiser, works on an epigenetic level to delay the ageing of skin cells and help even skin tone over time. When combined with antioxidants like Vitamin C (as in our 15% Vitamin C + EGF Serum), peptides amplify the brightening process through different complementary pathways.

Plumps Lips Naturally

The 6% Tripeptide Complex in our Tripeptide Plumping Lip Balm works at the surface of the lips to visibly increase volume and reduce fine lines, without the tingle or irritation of traditional chemical-based lip plumpers. This is peptide technology applied where it's most visible.

Reduces Under-Eye Puffiness and Firms the Eye Area

The delicate eye area is one of the first places to show signs of fatigue and ageing. Matrixyl 3000™ Peptide in our Caffeine Eye Cream works alongside 0.3% Caffeine to support collagen production in this thin-skinned area, plumping, firming, and smoothing while Caffeine tackles puffiness directly. 95% of users agreed skin felt instantly smoother and deeply hydratedafter use.

Visibly Lifts and Smooths the Eye Contour

For fine lines, crow's feet and loss of firmness specifically, the Tetrapeptide Complex in our Bio-Active Ceramide Eye Cream targets the eye contour directly. Paired with Bio-Active Ceramides, it's clinically proven to lift eyelids by 29% in 4 weeks**and deliver up to 4x wrinkle reduction*89% saw fine lines smoothed and blurred instantly*****.

Suitable for All Skin Types, Including Sensitive and Pregnant Skin

Peptides are among the most universally tolerated actives in skincare. They cause no irritation, no purging, and no sensitivity. They work equally well on oily, dry, combination, and sensitive skin. Every INKEY List peptide-containing product is also formulated to be safe during pregnancy and breastfeeding.

One of peptides' greatest advantages is how easily they slot into any routine. There's no complicated timing, no waiting periods, and no need to keep them away from other actives.

Where Peptides Sit in Your Routine

Apply peptide products in order of texture, thinnest to thickest, after cleansing. This means:

  1. Cleanser
  2. Hydrating Serum (e.g. Hyaluronic Acid Serum, applied to damp skin)
  3. Treatment Serum (e.g. 15% Vitamin C + EGF Serum or Exosome Glow Serum)
  4. Eye Treatment (e.g. Caffeine Eye Cream or Bio-Active Ceramide Eye Cream)
  5. Moisturiser (e.g. Peptide Moisturiser)
  6. SPF 30+ (AM only)
  7. Lip Balm (Tripeptide Plumping Lip Balm, can be applied anytime)

New to layering? Our complete skincare routine guide walks through the full order step by step.

How Much to Use

  • Hyaluronic Acid Serum: A pea-sized amount on damp skin, this is your hydration base
  • 15% Vitamin C + EGF Serum: A pea-sized amount, wait 60 seconds before the next layer
  • Caffeine Eye Cream: A pea-sized amount split between both eyes, pat gently around the orbital bone
  • Bio-Active Ceramide Eye Cream: A pea-sized amount, patted around the orbital bone from inner to outer corner. Not on the eyelid or waterline. How to apply eye cream properly
  • Peptide Moisturiser: A pea-sized amount massaged into face and neck
  • Tripeptide Lip Balm: A small amount directly to lips, at least 3x daily for best results

How Often?

All INKEY List peptide products are gentle enough for twice-daily use (AM and PM). For the Tripeptide Lip Balm, the more consistently you apply it, the faster and more pronounced the results. Aim for at least 3 applications per day for the full 4-week effect.

Morning vs Evening: Which Is Better?

How to Use Peptides
ProductMorning (AM)Evening (PM)
Hyaluronic Acid Serum✓ Recommended✓ Also effective
15% Vitamin C + EGF Serum✓ Recommended; antioxidant protection works hardest during the dayOptional; still effective
Exosome Glow Serum✓ Effective✓ Recommended
Caffeine Eye Cream✓ Helps depuff signs of overnight fatigue and creates a smooth makeup base✓ Supports overnight repair
Bio-Active Ceramide Eye Cream✓ Layers well under concealer✓ Recommended for line smoothing and lifting
Peptide Moisturizer✓ Lightweight enough for daily wear✓ Supports overnight skin renewal
Tripeptide Lip Balm✓ Use in the morning and throughout the day✓ Excellent as an overnight treatment

💡INKEY Tip:Apply your Hyaluronic Acid Serum to skin that's still slightly damp after cleansing. It enhances absorption and primes your skin to get more from every peptide product layered on top.

Peptides and Retinol, A Powerful Combination

Retinol and peptides are often compared, but they work through completely different mechanisms, which makes them an exceptional combination rather than competitors.

  • Retinol accelerates cell turnover, targeting the surface renewal of skin for anti-ageing results. It can cause initial irritation and requires careful introduction.
  • Peptides work at the signalling level, supporting collagen production and barrier function without any irritation risk.

Used together: Peptides are ideal in the AM routine, retinol in the PM. The peptides support barrier repair and hydration, which can reduce any dryness caused by retinol, making the combination particularly effective for those who are new to retinol or have sensitive skin. More in our retinol guide and what not to mix with retinol.

Peptides and Vitamin C, Better Together

Vitamin C and peptides address the skin's ageing process from two angles simultaneously:

  • Vitamin C neutralises free radicals, inhibits melanin production, and fades dark spots
  • Peptides (EGF) support skin cell renewal and elasticity

Our 15% Vitamin C + EGF Serum combines both in a single formula, 15% Ascorbyl Glucoside for brightening and 1% Epitensive™ EGF for regeneration. In a 4-week consumer trial, 87% of users agreed skin looks brighter, while 84% agreed skin looks healthier and less dull. Read more in our vitamin C guide.

Peptides and Hyaluronic Acid, INKEY's Signature Duo

This is the combination at the heart of our bestselling Hyaluronic Acid Serum. The 2% Multi-Molecular Hyaluronic Acid delivers immediate, deep hydration at multiple skin depths, while Matrixyl 3000™ Peptide works on the structural level to support firmer skin over time. Together, they give you instant plumping and long-term collagen support in a single step. More in our hyaluronic acid guide.

Peptides and Ceramides, Barrier Plus Structure

Ceramides and peptides do genuinely different jobs, which is why they work so well in one formula. Ceramides repair and strengthen your skin barrier, locking in moisture. Peptides signal skin to firm and lift. Our Bio-Active Ceramide Eye Cream combines both. Bio-Active Ceramides vs regular ceramides explained and what is Ceramide NP.

Peptides Ingredient Compatibility Guide

Peptides vs Other Ingredients
PairingSafe?Notes
Peptides + Hyaluronic Acid✓ Yes, idealHyaluronic Acid hydrates the skin while peptides provide targeted skin benefits. Use together daily.
Peptides + Vitamin C✓ YesLayer Vitamin C serum first, followed by Peptide Moisturizer, or use a formula that combines both.
Peptides + Niacinamide✓ YesApply Niacinamide after your hydrating serum and before Peptide Moisturizer.
Peptides + Ceramides✓ Yes, idealCombines barrier support with firming benefits. Both are found in our Bio-Active Ceramide Eye Cream.
Peptides + Retinol✓ Yes, split AM/PMUse peptides in the AM and retinol in the PM. They complement each other well.
Peptides + AHAs/BHAs✓ Yes, split AM/PMUse acids in the PM and peptides in the AM to support the skin barrier.
Peptides + SPF✓ Yes, alwaysAlways finish your morning routine with SPF 30+.

Hyaluronic Acid Serum - £12 | 30ml

The Hydrating Peptide Foundation

The INKEY List's bestselling serum - and the most-reviewed product in the range with over 3,100 five-star reviews - is also a powerful peptide delivery system. The hero is 2% Multi-Molecular Hyaluronic Acid, but it's the addition of Matrixyl 3000™ Peptide that elevates this from a hydration serum to a genuine firming treatment.

The formula:

  • 2% Multi-Molecular Hyaluronic Acid — holds up to 1,000x its weight in water, delivering instant hydration at multiple depths of skin
  • Matrixyl 3000™ Peptide (Palmitoyl Tetrapeptide-7 + Palmitoyl Tripeptide-1) — one of the most studied signal peptide complexes in skincare. Targets the appearance of fine lines and supports firmer-looking skin over time

Consumer test results (4-week independent study of 22 people under dermatological control):

  • 82% agreed skin felt firmer, smoother, and more elastic
  • 86% agreed the formula is quick-absorbing, lightweight, and non-tacky
  • Clinically proven to deliver instant hydration and reduce water loss

What it targets: Dehydrated skin | Fine lines & wrinkles | Damaged skin barrier

Suitable for: All skin types | Sensitive skin | Pregnancy & breastfeeding | Teen approved

Certifications: Vegan Society Certified | Leaping Bunny Cruelty-Free | Fragrance-Free | Clinically Tested

Awards: Allure Best of Beauty | CEW 2023 Award | Get the Gloss Gold | Glamour

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Caffeine Eye Cream - £12 | 15ml

The Peptide-Powered Eye Awakener

The Caffeine Eye Cream is clinically proven to improve the appearance of puffiness and dark circles from first use — and the peptide in its formula is what separates it from a basic caffeine product. Matrixyl 3000™ Peptide works in the delicate eye area to boost collagen production, plumping and firming the skin where it's thinnest and most vulnerable.

The formula:

  • 0.3% Caffeine — a natural antioxidant that tackles the fluid retention behind under-eye puffiness and dark circles
  • Matrixyl 3000™ Peptide (Palmitoyl Tetrapeptide-7 + Palmitoyl Tripeptide-1) — boosts collagen production to plump, firm, and smooth the delicate eye area
  • Albizia Julibrissin Bark Extract — specifically reduces signs of under-eye fatigue for brighter, more awake-looking eyes

Consumer test results (4-week independent study of 22 people under dermatological and ophthalmological control):

  • 95% agree skin feels instantly smoother and deeply hydrated
  • 95% agree it's quick-absorbing, lightweight, and does not pill
  • Clinically proven to improve puffiness & dark circles from 1st use
  • Clinically proven to deliver instant hydration

What it targets: Puffiness | Dark circles

Suitable for: All skin types | Sensitive skin | Pregnancy & breastfeeding

Certifications: Leaping Bunny Cruelty-Free | Fragrance-Free | Clinically Tested | Ophthalmologically Tested

Awards: Get the Gloss Gold | Vogue | Glamour | This Morning

💡 INKEY Tip: Store your Caffeine Eye Cream in the fridge for an extra cooling, depuffing boost on tired mornings.

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Bio-Active Ceramide Eye Cream, £15, 18ml

The Lifting & Line-Smoothing Peptide Eye Cream

Our most advanced eye formula, and a genuine peptide product. A Tetrapeptide Complex works alongside Bio-Active Ceramides to target the delicate eye area where the first signs of ageing appear. It smooths fine lines, hydrates the eye contour, and visibly lifts and sculpts.

The formula:

  • Tetrapeptide Complex (Tetrapeptide-111), a targeted peptide complex that smooths the look of fine lines and visibly lifts and firms the eye contour
  • 0.2% Bio-Active Ceramide NP, a clinically active ceramide that goes beyond the skin's surface, strengthening the barrier and supporting deeper skin renewal
  • 0.5% Liftilience, instantly lifts and sculpts the eye contour

Key claims:

  • Up to 4x wrinkle reduction*
  • Clinically proven to lift eyelids by 29% in 4 weeks**
  • Clinically proven to improve skin firmness & elasticity**
  • 89% saw fine lines smoothed and blurred instantly*****
  • Proven to lift eyelids by 51% in 12 weeks***
  • 94% agreed eye area looked visibly firmer and more sculpted**** (12 weeks)

What it targets: First signs of ageing around the eye | Fine lines & crow's feet | Crepey eyelids | Loss of firmness
Suitable for: Sensitive eyes | Pregnancy & breastfeeding
Certifications: Vegan Society Certified | Leaping Bunny | Fragrance-free | Alcohol-free | Dermatologist and ophthalmologist approved
Rated: 4.8 stars from 283 reviews

How to use: AM and PM. After cleansing and applying your serum, pat a pea-sized amount around the orbital bone, inner corner to outer. Do not apply to the eyelid or waterline.

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Which Eye Cream Is Right For You?

Both contain peptides. They solve different problems, and they're designed to work together.

Want to target everything?Layer Caffeine Eye Cream first, then Bio-Active Ceramide Eye Cream on top. More on the difference in ourdark circles and puffiness guide.

The INKEY List Peptide Products
Caffeine Eye CreamBio-Active Ceramide Eye Cream
Main ConcernPuffiness, dark circles, tired-looking eyesFine lines, crow's feet, loss of firmness
Key PeptideMatrixyl 3000™Tetrapeptide Complex
Also Contains0.3% Caffeine, Albizia JulibrissinBio-Active Ceramide NP, Liftilience
TextureLightweight, fast-absorbingLightweight yet rich and silky
Size15ml18ml
Price£12£15

15% Vitamin C + EGF Serum - £16 | 30ml

The Brightening + Renewal Peptide Serum

This is where brightening and peptide technology meet. The 15% Vitamin C + EGF Serum uses 15% Ascorbyl Glucoside - a stable, gentle form of Vitamin C - alongside 1% Epitensive™ EGF, a plant-derived Epidermal Growth Factor peptide that signals skin cells to renew and regenerate. The result: a serum that brightens what's already there while encouraging the generation of healthier skin underneath.

The formula:

  • 15% Ascorbyl Glucoside — stabilised Vitamin C that converts to active form on contact with skin. Targets melanin production, fades dark spots, provides antioxidant protection
  • 1% Epitensive™ EGF (Oligopeptide-1) — plant-derived Epidermal Growth Factor by Lipotrue. A signalling peptide that stimulates skin cell renewal and regeneration, supporting elasticity and firmness over time

Consumer test results (4-week independent consumer trial of 64 people):

  • 87% agree skin looks brighter
  • 88% saw visible improvement in skin tone and texture
  • 84% agree skin looks healthier and less dull

What it targets: Hyperpigmentation | Dull skin | Uneven skin tone

Suitable for: All skin types | Sensitive skin | Pregnancy & breastfeeding

Certifications: Vegan Society Certified | Leaping Bunny Cruelty-Free | Fragrance-Free | Dermatologically Tested

Awards: Glamour | ELLE | Marie Claire | Good Housekeeping

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Peptide Moisturiser - £16 | 50ml

The Anti-Ageing Daily Moisturiser

The Peptide Moisturiser is built around two of the most targeted peptide technologies in INKEY's range. Royal Epigen P5™works at an epigenetic level — influencing how skin cells express themselves over time to delay the visible signs of ageing and even skin tone. Diffuporine (Acetyl Hexapeptide-37) supports the skin's moisture barrier from within, helping to maintain hydration and a visibly radiant complexion.

The formula:

  • 2% Royal Epigen P5™ (Pentapeptide-48) — an epigenetic peptide that delays the ageing of skin cells and helps even skin tone. Designed to accelerate skin renewal for smoother, more even-looking skin
  • 1% Hydrating Peptide Solution (Diffuporine / Acetyl Hexapeptide-37) — targets the skin's moisture barrier to hydrate, improve barrier function, and support a visibly radiant complexion

What it targets: Fine lines & wrinkles | Dry skin | Damaged skin barrier

Suitable for: All skin types | Sensitive skin | Pregnancy & breastfeeding

Certifications: Vegan Society Certified | Leaping Bunny Cruelty-Free | Fragrance-Free | Gluten-Free

Awards: Allure

How to use: AM and PM. After cleansing and hydrating, gently massage a pea-sized amount into face and neck. Follow with SPF in your AM routine.

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Tripeptide Plumping Lip Balm - £11 | 10ml

The Science-Backed Lip Plumper

Most lip plumpers work by irritating the lips into temporary swelling. This one takes the opposite approach - using 6% Tripeptide Complex to naturally stimulate lip volume over time and 2% Ultra Filling Spheres (which deliver Hyaluronic Acid directly into the lip surface) to smooth, hydrate, and plump from within. No tingle. No irritation. Just real, measurable results.

The formula:

  • 6% Tripeptide Complex (Palmitoyl Tripeptide-1 + Palmitoyl Tripeptide-38) — visibly increases lip volume and definition over time by targeting the natural structural mechanisms of the lips
  • 2% Ultra Filling Spheres — dehydrated Hyaluronic Acid that expands on contact with moisture, delivering immediate plumping and locking in hydration to smooth fine lines on and around the lips

Consumer test results (4-week independent clinical study of 20 people):

  • Clinically proven to plump lips by up to 40% in 4 weeks
  • Visibly smoothed fine lines on lips in 2 weeks
  • 95% felt the balm instantly nourished and hydrated the lips

What it targets: Lip volume | Dry, cracked lips | Fine lines around the mouth

Available in: Clear | Mocha | Pink | Berry

Suitable for: All skin types | Pregnancy & breastfeeding

Certifications: Vegan Society Certified | Leaping Bunny Cruelty-Free | Fragrance-Free | Clinically Tested

Awards: Allure | Glamour | Get the Gloss | Sheerluxe

How to use: Apply a small amount to clean lips at least 3x daily. Use consistently for 4 weeks to see the full volume benefit. Wear alone or layered over lip colour.

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Exosome Glow Serum, £20, 30ml

The Advanced Peptide + Exosome Serum

Our most advanced serum pairs 1% Cica Exosome with 1% Kollaren, a smart peptide that supports firmness and renewal.

  • 100% saw more glowing skin, clinically proven†
  • Clinic worthy rejuvenated skin in 14 days†
  • 6-in-1 skin rejuvenation: clinically proven to visibly improve radiance, hydration, tone, firmness, elasticity and texture†
  • Proven to deliver up to 12 hours of hydration††
  • Helps support natural collagen production

†4-week clinical study of 26 people. ††Clinical study of 31 people.

Learn more in our exosomes guide.

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Not All Peptides Do the Same Thing, Specificity Matters

When choosing a peptide product, the most important question isn't "does it contain peptides?" It's: which peptides, at what concentration, and what are they designed to do?

A product labelled "with peptides" could contain a trace amount of a single peptide at a concentration too low to have any meaningful effect. INKEY's approach is the opposite: named peptide complexes at validated concentrations, with a clear explanation of what each one does.

What to Look for in Peptide Products
ConcentrationLevelWho It's For
Trace / under 1%Supporting roleOften found in combination products; provides supportive rather than targeted benefits.
1–2%Active treatment levelThe concentration range used across INKEY's peptide products.
5–6%+High-strength targeted deliveryUsed in specialized applications such as our Tripeptide Lip B

Supporting Ingredients to Look For

  • Hyaluronic Acid, immediately hydrates and plumps, amplifying the firming effect of peptides
  • Ceramides, strengthen the barrier so peptides can work in better conditions
  • Vitamin C (Ascorbyl Glucoside), brightens and protects, working alongside peptides
  • Shea Butter / Emollients, help deliver peptides deeper into the skin in moisturiser formulas
  • Squalane, plant-derived barrier support that aids absorption without clogging pores

Format Guide

What to Look for in Peptide Products
FormatBest ForINKEY ExamplePrice
SerumHighest concentration delivery; active treatment stepHyaluronic Acid Serum (Matrixyl 3000™)£12
Serum with Vitamin CBrightening + renewal in one step15% Vitamin C + EGF Serum£16
Advanced SerumGlow, firmness and renewalExosome Glow Serum£20
Eye CreamPuffiness and dark circlesCaffeine Eye Cream£12
Eye CreamFine lines, lifting and firmingBio-Active Ceramide Eye Cream£15
MoisturiserDaily peptide maintenance + hydrationPeptide Moisturiser£16
Lip BalmSpecialized volume and repair for the lipsTripeptide Plumping Lip Balm£11

Are Peptides Safe?

Yes. Peptides are one of the most extensively researched and universally well-tolerated categories of skincare ingredients. Because they work by mimicking signals that already exist within the skin's biology, they don't disrupt, irritate, or strip the way stronger actives can.

There is no purging phase. There is no initial irritation period. There is no need to introduce them gradually. You can start using peptide products daily from day one.

Potential Side Effects

There are no established side effects associated with topical peptide use at the concentrations used in skincare. Unlike retinol, AHAs, or high-concentration Vitamin C, peptides do not sensitise, exfoliate, or cause photosensitivity.

Who Should Take Care

  • Those using prescription retinoids or active medications: Always check with your GP or dermatologist before adding new skincare actives
  • Patch testing: INKEY always recommends patch testing any new product before full-face application. Why patch testing matters

Peptides and Pregnancy

All INKEY List peptide-containing products are formulated to be safe during pregnancy and breastfeeding. If you have specific concerns, always consult your midwife or healthcare provider. Read our full pregnancy-safe skincare guide

Application Tips

Apply in the right order. Thinnest formula first, thickest last. Your Hyaluronic Acid Serum goes on damp skin immediately after cleansing; your Peptide Moisturiser goes on last before SPF.

Don't rush the layering. Wait 60 seconds after applying a serum before applying the next product. This prevents pilling and ensures each ingredient is properly absorbed.

For the Tripeptide Lip Balm, consistency is everything. The tripeptide complex builds cumulative volume over time. Three or more applications per day, every day, for four weeks is what delivers the clinical result.

Apply eye creams with your ring finger. It applies the least pressure, protecting the delicate orbital area. Pat, never rub, around the eye contour.

Layering both eye creams? Caffeine first, Bio-Active Ceramide on top. Give each 30 to 60 seconds to absorb.

Common Mistakes to Avoid

Expecting results in days. Peptides are a long-game ingredient. Hydration and texture improvements come first (within 1 to 2 weeks); firming and structural changes develop over 4 to 8 weeks of consistent use.

Thinking peptides replace retinol. They don't, they complement it. Use both in split AM/PM routines for the most comprehensive anti-ageing approach.

Using a face moisturiser around the eyes. Your regular moisturiser isn't formulated for the thinner skin around the eye. A targeted eye formula is optimised for that zone.

Under-dosing the Lip Balm. Three times daily is the minimum for the 4-week transformation.

How Long Until You See Results?

Expert Tips & Pro Advice
TimelineWhat to Expect
ImmediatelyInstant hydration from Hyaluronic Acid Serum; immediate cooling and depuffing from Caffeine Eye Cream; 89% saw fine lines smoothed and blurred instantly with Bio-Active Ceramide Eye Cream*****
Week 1–2Skin feels more hydrated with a smoother texture; lip lines begin to visibly soften.
Week 3–4Visible improvement in skin firmness; brighter-looking complexion from 15% Vitamin C + EGF Serum; meaningful increase in lip volume; 29% eyelid lift with Bio-Active Ceramide Eye Cream**
Week 6–8Continued improvement in the appearance of fine lines, elasticity and overall skin tone.
Week 12+Sustained firming; 51% eyelid lift and 94% agreed the eye area looked visibly firmer***/****

Why Matrixyl 3000™?

One of the best-studied signal peptide complexes available to cosmetic formulators. Its two components, Palmitoyl Tripeptide-1 and Palmitoyl Tetrapeptide-7, work synergistically to support fibroblasts (the cells responsible for producing collagen) while helping protect the collagen that's already there.

Why Tetrapeptide Complex?

Developed specifically for the eye contour, where skin is thinnest and expression lines show first. In our Bio-Active Ceramide Eye Cream it's paired with Bio-Active Ceramides so the formula works on two fronts at once: visible line smoothing and lifting on the surface, barrier strengthening underneath. That pairing is what delivers a clinically measured 29% eyelid lift in 4 weeks**.

Why Epitensive™ EGF?

EGF (Epidermal Growth Factor) occurs naturally in the body and plays a key role in cell signalling. Our 1% Epitensive™ is sourced from Lipotrue and produced through biotechnology rather than from animal sources, making it suitable for vegans and more sustainably produced than many EGF alternatives.

Why Royal Epigen P5™?

An epigenetic peptide, meaning it works at the level of gene expression, influencing how skin cells behave rather than simply providing structural support. At 2% in our Peptide Moisturiser, it helps delay the visible ageing of skin cells and evens skin tone through a mechanism distinct from brightening actives like Vitamin C.

Why 6% Tripeptide Complex?

Formulated at a clinically validated 6% concentration, the level at which it delivers the measured 40% volume increase in the 4-week clinical trial. Lower concentrations would not deliver the same result.

Our Quality Standards

  • Dermatologically tested
  • Fragrance-free
  • Vegan Society Certified (where applicable)
  • Leaping Bunny Certified
  • 100% Recyclable Packaging
  • Pregnancy-safe formulations

The Gold Standard Morning Routine (Anti-Ageing + Brightening)

Complete Your Peptide Routine
StepProductBenefit
1. CleanseYour INKEY cleanserCreates a fresh, clean canvas.
2. HydrateHyaluronic Acid Serum (to damp skin)Instant hydration + Matrixyl 3000™ firming support.
3. Treat15% Vitamin C + EGF SerumBrightening + EGF-powered skin renewal.
4. EyeCaffeine Eye CreamDepuffs, firms and hydrates the eye area.
5. MoisturisePeptide MoisturiserLocks in treatment + ongoing anti-ageing support.
6. ProtectSPF 30+Non-negotiable. Protects your results throughout the day.
7. LipsTripeptide Plumping Lip BalmHydrates and helps build the appearance of lip volu

Evening Routine (Repair + Renewal)

Complete Your Peptide Routine
StepProductBenefit
1. CleanseYour INKEY cleanserRemoves SPF and daily buildup.
2. HydrateHyaluronic Acid Serum (to damp skin)Replenishes moisture overnight.
3. TreatRetinol (if using) or Exosome Glow SerumSupports skin cell turnover and renewal.
4. EyeBio-Active Ceramide Eye CreamSmooths fine lines, lifts and firms the eye contour.
5. MoisturisePeptide MoisturiserSupports the skin barrier and overnight renewal.
6. LipsTripeptide Plumping Lip BalmSupports overnight plumping and repair.

Power Combinations

Complete Your Peptide Routine
PairingResultHow
Hyaluronic Acid Serum + Peptide MoisturiserHydration + firming from first useApply Hyaluronic Acid Serum to damp skin, then follow with Peptide Moisturiser.
15% Vitamin C + EGF Serum + Hyaluronic Acid SerumBrightening + firming + plumpingApply Hyaluronic Acid Serum first to damp skin, then layer 15% Vitamin C + EGF Serum.
Caffeine Eye Cream + Bio-Active Ceramide Eye CreamDepuffing + line smoothing and liftingApply Caffeine Eye Cream first, then layer Bio-Active Ceramide Eye Cream on top.
Peptides (AM) + Retinol (PM)Complete anti-ageing routineUse peptides in the AM and retinol in the PM.

Peptides aren't a trend. They're one of the most scientifically grounded categories in modern skincare, with decades of research behind them and real, measurable results that build with every application. Whether you're just beginning to think about anti-ageing, looking to firm and hydrate dehydrated skin, or wanting to naturally plump your lips without needles or irritation - peptides deliver.

Start with the Hyaluronic Acid Serum at £12 - the most-reviewed product in the INKEY range, and one of the most effective peptide-powered hydration serums available at any price. From there, build your peptide routine product by product, concern by concern.

Apply consistently. Layer intelligently. Trust the process.

Shop INKEY Peptides

*12-week independent clinical study of 30 people, comparing Ceramide NP at 0.2% vs a placebo formulation. **Clinically tested on 32 participants over 28 days. ***Clinically tested on 32 participants over 12 weeks. ****Tested on 32 participants over 12 weeks. *****Tested on 32 participants.

Peptides are short chains of amino acids that act as signalling molecules in the skin. Depending on the type, they can support collagen production, strengthen the moisture barrier, even skin tone, reduce the appearance of fine lines, and promote skin cell renewal. Unlike most actives, they work with your skin's own biology rather than disrupting it.