What Are Peptides in Skincare — and Do They Actually Work?
Peptides have become one of the most prominent ingredients in premium skincare. They appear in serums, eye creams, moisturisers, and increasingly in clinical formulations alongside prescription actives. The marketing around them ranges from precise to vague, and it can be difficult to know what's genuinely evidence-backed versus what's sophisticatedsounding filler.
Here's a clear, accurate answer to what peptides are, how they work on skin, and what the evidence actually supports.
What peptides are
Peptides are short chains of amino acids — the building blocks of proteins. When a chain is short (typically 2–50 amino acids), it's called a peptide. When it's longer, it becomes a protein.
The proteins most relevant to skin structure are collagen, elastin, and fibronectin. Collagen in particular is the primary structural protein of the dermis — responsible for skin thickness, firmness, and resilience. As collagen degrades with age, UV exposure, and hormonal change, the skin loses the structural integrity that produces its youthful appearance.
Peptides in skincare are designed to interact with skin biology — either by signalling cells to produce more of certain proteins, carrying specific molecules to where they're needed, or inhibiting processes that degrade skin structure.
The main types of skin peptides
Signal peptides (matrikines)
These are fragments of extracellular matrix proteins — naturally occurring breakdown products that serve as biological signals. When collagen breaks down, it releases small peptides that signal fibroblasts to produce more collagen. Synthetic signal peptides mimic this process.
The most studied include palmitoyl pentapeptide-4 (also known as Matrixyl), palmitoyl tripeptide-1, and palmitoyl tetrapeptide-7. Clinical studies show increases in collagen and hyaluronic acid production with consistent use. The evidence base isn't as extensive as tretinoin, but it's genuine.
Carrier peptides
These stabilise and deliver trace elements (particularly copper and manganese) to the skin that are essential for enzyme function in collagen and elastin synthesis. Copper peptides are the best-studied example — they've shown evidence for wound healing support and collagen stimulation. GHK-Cu (copper tripeptide-1) is the most clinically referenced.
Enzyme-inhibiting peptides
These inhibit enzymes that break down skin proteins. Soy peptides, for example, inhibit protease activity that degrades collagen. The mechanism is protective rather than stimulatory — slowing degradation rather than building new protein.
Neurotransmitter-inhibiting peptides
These work similarly to neurotoxin injectables — reducing the muscle contractions that cause expression lines. Acetyl hexapeptide-3 (Argireline) is the most common example. Evidence shows some reduction in expression line depth with consistent topical use, though less dramatically than injectable neurotoxins.
Do peptides actually work?
The honest answer: yes, with appropriate expectations.
Peptides have genuine clinical mechanisms and real evidence in peer-reviewed literature. The limitations are:
Concentration and delivery. Many commercial products contain peptides at concentrations too low to produce meaningful biological effects. The evidence for signal peptides comes from studies using specific concentrations in appropriate vehicles — retail products often don't match the study conditions.
Penetration. Peptides are hydrophilic molecules that don't naturally penetrate the skin barrier efficiently. Delivery technology — encapsulation, lipophilic conjugation (the "palmitoyl" prefix on many peptides) — improves penetration but varies significantly between formulations.
They're not tretinoin. Prescription tretinoin has over 40 years of peer-reviewed evidence showing measurable increases in dermal collagen density, improved skin thickness, and structural change. Peptide evidence is real but less extensive and the effect sizes are more modest. They work best as an adjunct to a prescription retinoid foundation — not as a replacement.
Peptides alongside prescription skincare
The most effective approach combines the evidence-backed foundation of prescription tretinoin with peptides that complement its mechanism:
Tretinoin stimulates collagen through retinoic acid receptor activation in fibroblasts
Signal peptides stimulate collagen through a different receptor pathway — the two are additive, not redundant
Copper peptides support the enzymatic processes that build the collagen tretinoin has stimulated
This is why compounded prescription formulas that include peptides alongside tretinoin are clinically more comprehensive than either alone. Read more about what peptides do alongside tretinoin and the emerging clinical case for combination formulas.
Getting peptides in a prescription skincare context
At Laevo, we're developing compounded formula options that incorporate evidence-based peptides alongside the Core Formula's tretinoin base — providing the additive collagen-support benefit within a clinically designed prescription framework.
Read more about what prescription compounding allows and why individualised formulas can incorporate peptides at clinically relevant concentrations.
The Laevo assessment takes 5 minutes.
Assessment fee applies. Prescription required — not all applicants will be approved. Individual results vary. This article is for informational purposes only and does not constitute medical advice.
