Whether you're browsing the skincare aisle at the department store, or scrolling online you've probably come across the term 'peptides'.

Touted for their skin-enhancing benefits, peptides have risen to prominence amongst skincare obsessives thanks to their reputation as a "does it all" group of skincare ingredients.

Whether it's a rich night cream packed with collagen peptides, or a hydrating serum full of growth factor peptides; chances are you'll spot peptides somewhere on the list of ingredients in new, exciting skincare products.

But, while they promise to support collagen production, increase skin cell turnover, smooth fine lines and wrinkles and prevent premature ageing, thanks to their high-tech nature, they're one of the trickier categories of skincare actives to understand.

With this in mind, we've taken a deep dive into the science behind peptides, to understand why exactly you should be prioritising them in your skincare routine.

What are peptides?

Understanding the structure of the skin is essential for grasping the magic of peptides.

Our skin is made up of proteins like collagen, elastin and keratin — these proteins are considered the fundamental building blocks of a healthy complexion.

They're essential macromolecules that play a crucial role in wound healing, skin cell turnover and skin barrier function. The compounds we refer to as "peptides" are actually short-chain amino acids that form the basis of these proteins [1].

As we age, these proteins break down; a process that can be accelerated by UV radiation, environmental pollution and certain lifestyle factors.

Over the last 40 years, a wealth of scientific evidence has accumulated demonstrating that the use of peptides in topical skincare products can help slow the ageing process and address everything from crepey skin to uneven skin tone and sagging skin [2].

How do peptides work?

The first rule of peptides? Not all peptides are the same, and when looking at peptide skincare products, it's important to understand which types of peptides they include, and whether they will target your specific skin concerns.

The easiest way to understand the benefits of peptides for skin is to think of them as "messengers".

Applied topically, whether in your serums, moisturisers or eye creams, peptides help your skin cells function optimally. They do this by either "blocking" or activating" receptors in the skin which.

This can mean controlling a muscle contraction that forms a fine line over time, decreasing skin reactivity or promoting skin cell renewal, something which slows down as we age [3].

What is the best peptide for me?

These all sound like desirable results (we all want smooth, glowing complexions after all) and that's why there's rarely a single "best" peptide for you.

Instead, you'll usually find a combination of peptides in any skincare product. We've broken down the four main peptides you'll find below.

Signalling peptides

Peptides called "signal peptides" are some of the most commonly used in skincare. These peptides are prized for their skin cell-communicating properties; they've been shown to "signal" fibroblasts to kick into action, moving our complexion into rejuvenation mode and boosting collagen and elastin levels [4].

Neurotransmitter peptides

Peptides can also perform a function called "neurotransmitter inhibition". These neurotransmitter peptides can block the release of the chemicals that trigger muscle contractions and expression lines.

By minimising the intensity of repeated facial movements they have an immediate smoothing effect, minimising the appearance of fine lines. Think of the action of some anti-wrinkle injectibles and you'll have an idea. The benefit of peptides is that they're much cheaper and pain-free [5].

Carrier peptides

Then, there are carrier peptides. These are some of the most versatile peptides found in skincare as they help other active ingredients penetrate the skin, increasing the overall efficacy of skincare formulations.

One of the most common carrier peptides is copper peptides. Copper peptides, sometimes referred to as copper tripeptide growth factor, quite literally deliver copper to the dermis.

Here it plays a role in the formation of enzymes like superoxide dismutase, an antioxidant and lysyl oxidase, an enzyme critical to the body's ability to produce collagen [6][7]. They have been shown to stimulate the production of fibroblast growth factors assisting with wound healing [8].

Enzyme inhibitor peptides

You can probably guess what enzyme inhibitor peptides get up to when included in a skincare product. These peptides are designed to inhibit the action of enzymes that cause the degradation of collagen and elastin in the skin [9].

These peptides can slam the breaks on enzymes produced by the body that degrade existing collagen, making them highly effective preventative anti-ageing ingredients.

Antimicrobial peptides

A newer kid on the block, pharmaceutical scientists are excited about the potential of antimicrobial peptides.

These new peptides — referred to as AMPs — are not only packed with antioxidants, but because of their antimicrobial effects, could provide a gentle alternative to many anti-acne treatments currently on the market [10].

Are peptides better than other skincare ingredients?

Peptides sound like a fix-all ingredient, so should you be switching out the retinol, hyaluronic acid hydrating serums and vitamin C products for peptide-only products? Not so fast!

Think of peptides as the best-supporting players in your skincare routine, helping your other active ingredients work harder and smarter.

An additional benefit of peptides is they don't place the additional stress on the skin that some more of the intensive actives do; meaning they can be included in formulations with other actives without risking overstimulating the skin.

Here's how peptides can boost the performance of other skincare actives.

How peptides can work with retinol

Retinol and vitamin A derivatives are considered the gold standard in anti-ageing skincare [11]. They encourage cell renewal by increasing skin cell turnover — this means they're extremely effective actives for those looking to firm skin and address multiple signs of ageing. But, they can be irritating for people with sensitive skin.

One benefit of peptides is they can be used day and night, whereas dermatologists generally recommend only using vitamin A anti-ageing products at night.

This means using peptides in tandem with retinol can help supercharge your skincare results. Retinol and peptides are increasingly being paired together in skincare formulations to provide double benefits for your skin [12].

What about hyaluronic acid?

Comparing peptides with hyaluronic acid is a little like comparing apples and oranges; they're both delicious skincare ingredients, and they work very differently. Hyaluronic acid is commonly found in products designed to hydrate skin; while peptides as we've established are all round anti-agers.

Hyaluronic acid binds 1000 times its weight in water, meaning application plumps skin, and leaves it feeling soft.

But, while a hyaluronic acid hydrating serum might reduce the appearance of fine lines and wrinkles while you're using it, as well as targeting dry skin, it's not going to kick your skin cells into action in the same way retinol or peptides will.

However, some of the best peptide-based skincare uses hyaluronic acid for instant skin soothing and superficial plumping benefits, while peptides get to work on creating a healthier complexion in the long term [13].

By combining hyaluronic acid with peptides, your skin will reap instant and long-term plumping and anti-ageing benefits.

Peptides and vitamin C

Peptides and vitamin C are another ingredient pairing that works wonderfully. Vitamin C, or L-ascorbic acid, is favoured for its skin-brightening benefits [14].

The ingredient has been demonstrated to reduce signs of photoageing like dark spots and fine lines and provide an antioxidant shield that neutralises the damaging effects of free radicals, while also stimulating collagen production [15].

Peptides are a perfect complement to vitamin C as they strengthen the skin barrier, making skin more resilient to environmental aggressors.

How to use peptides

Like all skincare ingredients, the efficacy of peptides depends on the amount of time they spend in contact with the skin.

This means you should look for peptides in skincare products that remain on the skin for long periods of time; think serums, eye creams and moisturisers rather than wash-off cleansers.

Ensuring you apply your peptide-based products to clean skin following a gentle cleanse morning and night will ensure you fully reap the benefits of what is an exceptional anti-ageing ingredient.

So in summary, what can you expect peptides to achieve in your skincare routine?

If you're applying a peptide serum, eye cream or rich night moisturiser you can expect peptides to do a number of things for your skin.

They act as messaging agents, kickstarting the production of new skin cells and healing processes. As peptides increase collagen production you can expect plumper skin as well as improvements in skin texture with consistent use.