Peptides in Skincare: The Future of Youthful, Healthy Skin

Peptides are a hot topic right now, one of the most talked-about ingredients in cosmetic products. Dr Tiina Meder explains why peptides are so exciting and in particular her go-to class of ingredients for a variety of skin concerns. 

Peptides are one of the most exciting ingredients in modern skincare, and I’ve been passionate about them since 2009. In fact, my first product under the Meder brand was based on peptides, and their appearance on the market revolutionized my professional journey. Before that, I worked as a top research and education manager in major skincare brands, traveling globally and training professionals. But when I first learned about peptides at a raw material conference, I was captivated. Here was a category of ingredients that could be more effective than traditional actives like retinol, yet completely safe, with no side effects or discomfort, and biologically identical to our own tissues.

Peptides are short chains of amino acids — the fundamental building blocks of proteins like collagen, elastin, and keratin. These proteins are essential for skin strength, elasticity, hydration, and overall health. Because peptides are small molecules, they can penetrate the skin more easily than larger proteins, making them highly effective in topical formulations.

Back in 2006, only a handful of peptides were registered for cosmetic use. Today, that number exceeds 600, and by 2030, it’s projected to surpass 1,000. With so many peptides available, it’s clear they are not a one-size-fits-all solution. Different peptides serve different functions — some boost collagen, others relax muscles, and some target pigmentation or inflammation.

Peptides act as messengers within the skin, communicating between cells through a process called intercellular communication. They send signals to stimulate collagen and elastin production, calm inflammation, and even regulate pigmentation. For example, certain peptides tell fibroblasts to produce more collagen, helping to reduce wrinkles and improve skin firmness. Others can instruct pigment cells to produce less melanin, addressing hyperpigmentation.

Peptide size is a crucial factor in their effectiveness in skincare, and it’s governed by what’s known as the 500 Dalton Rule. This scientific principle states that for any molecule to effectively penetrate the skin barrier and reach the deeper layers where it can have a biological effect, its molecular weight must be less than 500 Daltons. Each amino acid typically weighs between 80–110 Daltons, so peptides composed of about 5–6 amino acids are generally small enough to pass through the skin’s outermost layer (the stratum corneum).

Why does this matter? Peptides that are small enough can act as messengers, signaling skin cells to produce more collagen, elastin, or other proteins essential for firmness and resilience. Larger peptides — those above 500 Daltons — are much less likely to penetrate the skin on their own. However, advances in formulation, such as attaching fatty acids or using delivery systems like liposomes, can help larger peptides reach their target.

Because peptides are biologically identical to those produced naturally in our bodies, they are safe and rarely cause allergic reactions or irritation. They are also dose-dependent — meaning the concentration in the product matters greatly. Many brands underuse peptides, leading to disappointing results, so choosing well-formulated products is crucial.

Peptides can also support skin hydration by enhancing the skin barrier. This makes them effective for dry, dull, or aging skin, and they can even help reduce redness and irritation by strengthening the skin’s defences.

Despite their promise, several myths persist. Some believe peptides can’t penetrate the skin, but their small size and advances in formulation technology prove otherwise. Others worry about irritation, but well-formulated peptide products are gentle and non-sensitizing. However, not all peptide products are created equal: “Peptides are dose-dependent and expensive, so low concentrations may not deliver results. Always choose products from reputable brands with transparent ingredient lists.”

Another misconception is that peptides work overnight. While some calming peptides can soothe skin quickly, most benefits — like wrinkle reduction or improved firmness — take several weeks of consistent use. Patience and consistency are key.

It’s also crucial not to mix peptide serums with strong acids or retinoids, as these can degrade the peptide structure and reduce their efficacy. Instead, use peptides in a simple, well-structured routine for best results.

Incorporate peptides into your routine through serums and creams, which provide prolonged contact and better absorption. Use them consistently — results take time, often several weeks to months. Combine peptides with ingredients like hyaluronic acid, niacinamide, plants extracts and stem cells for enhanced effects.

Peptides are versatile and can be formulated to target various skin concerns—from aging and loss of firmness to redness and sensitivity. They are the building blocks for a healthier, more resilient skin barrier, and their potential continues to grow with ongoing scientific research.

In conclusion, peptides are truly the future of skincare. They offer a safe, effective, and scientifically backed way to support skin health, restore firmness, and reduce signs of aging. As science advances, I believe we’ll see peptides in nearly every skincare formulation—helping us achieve healthier, more youthful skin at any age.