The Role of Peptides in Modern Skincare

Peptides have become one of the most discussed ingredients in modern skincare, appearing in everything from high-street moisturisers to clinical-grade serums. But what exactly are peptides, how do they work, and do they live up to the marketing claims? At Axiom Aesthetics, we take an evidence-based approach to skincare recommendations, and peptides represent one of the most genuinely exciting developments in topical skin science.

Understanding Peptides

What Are Peptides?

Peptides are short chains of amino acids — the building blocks of proteins. While proteins like collagen and elastin may contain thousands of amino acids linked together, peptides typically consist of 2-50 amino acids. When a chain exceeds 50 amino acids, it is generally classified as a protein.

In the context of skincare, peptides function as signalling molecules. They communicate with skin cells, instructing them to perform specific functions such as producing more collagen, reducing inflammation, or improving barrier function. Think of peptides as text messages that tell your skin cells what to do.

How Peptides Work in the Skin

When applied topically, peptides can penetrate the outermost skin layers and interact with receptors on cell surfaces. This triggers intracellular signalling cascades that modify cell behaviour. The specific effect depends on the peptide’s sequence — different amino acid arrangements produce different biological signals.

Research published in the International Journal of Molecular Sciences (2023) has identified over 700 bioactive peptides with documented effects on skin cells. However, only a fraction of these have been successfully formulated for topical delivery and demonstrated clinical efficacy in controlled studies.

Types of Peptides in Skincare

Signal Peptides (Collagen-Stimulating Peptides)

Signal peptides instruct fibroblasts to produce more collagen, elastin, and other extracellular matrix components. They work on the principle that when collagen breaks down, the resulting peptide fragments signal the body to produce replacement collagen. By applying similar peptides topically, you can mimic this signal and stimulate collagen production without waiting for breakdown to occur.

Key signal peptides include:

• Palmitoyl pentapeptide-4 (Matrixyl): One of the most studied skincare peptides. Clinical trials published in the International Journal of Cosmetic Science demonstrated that Matrixyl reduced wrinkle depth by up to 36% over 4 months when applied twice daily
• Palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7 (Matrixyl 3000): A peptide combination that stimulates both collagen and hyaluronic acid production. Studies show improvements in skin firmness and wrinkle reduction comparable to retinol, but with significantly less irritation
• Palmitoyl tripeptide-38 (Matrixyl Synthe’6): Stimulates the production of six major components of the extracellular matrix, including collagen types I, III, and IV, plus fibronectin and hyaluronic acid

Neuropeptides (Neurotransmitter-Inhibiting Peptides)

Neuropeptides work by interfering with the neuromuscular signals that cause muscle contraction — the same principle behind botulinum toxin, though with significantly milder effects. They are sometimes called “Botox in a jar,” though this description overstates their potency.

• Acetyl hexapeptide-3 (Argireline): The best-known neuropeptide in skincare. It inhibits the SNARE complex involved in neurotransmitter release, reducing the depth of expression lines. Clinical studies show wrinkle depth reduction of 17-27% with consistent use over 2-4 weeks. While not a replacement for injectable anti-wrinkle treatment, it provides a noticeable softening effect
• Pentapeptide-18 (Leuphasyl): Works through a different mechanism than Argireline, targeting the enkephalin receptor. When combined with Argireline, the two peptides show synergistic effects, with combined wrinkle reduction exceeding either peptide alone
• Dipeptide diaminobutyroyl benzylamide diacetate (SYN-AKE): Inspired by the mechanism of waglerin-1, a peptide found in temple viper venom. It acts as a muscular nicotinic acetylcholine receptor antagonist, reducing micro-contractions that contribute to expression lines

Carrier Peptides (Metal Transport Peptides)

Carrier peptides deliver essential trace minerals to the skin, facilitating enzymatic processes and wound healing:

• GHK-Cu (copper tripeptide-1): Perhaps the most versatile skincare peptide. GHK-Cu delivers copper to cells, activating enzymes involved in collagen synthesis, antioxidant defence, and tissue repair. Research shows it can tighten skin, improve elasticity, reduce fine lines, and accelerate wound healing. Studies in Experimental Gerontology found that GHK-Cu increased collagen synthesis in skin fibroblasts by 70%
• Manganese tripeptide-1: Delivers manganese, a cofactor for superoxide dismutase (SOD) — one of the body’s most important antioxidant enzymes. Supports cellular defence against oxidative stress

Enzyme Inhibitor Peptides

These peptides work by blocking enzymes that break down skin proteins:

• Soybean peptides: Inhibit matrix metalloproteinases (MMPs) — the enzymes responsible for collagen and elastin degradation. By slowing protein breakdown, they help maintain existing collagen reserves
• Silk fibroin peptides: Have been shown to inhibit tyrosinase, the enzyme involved in melanin production, making them useful for addressing hyperpigmentation

Antimicrobial Peptides (AMPs)

These peptides have antibacterial, antifungal, and anti-inflammatory properties:

• Defensins: Natural antimicrobial peptides produced by the skin. Synthetic versions are being incorporated into skincare for acne-prone and infection-susceptible skin
• Cathelicidins: Including LL-37, which modulates the immune response and has been studied in the context of rosacea and acne treatment

How to Use Peptides Effectively

Formulation Matters

A peptide’s effectiveness depends heavily on its formulation. Key factors include:

• Concentration: The peptide must be present at a concentration sufficient to produce a biological effect. Many products include peptides at token levels for marketing purposes (“fairy-dusting”) without providing a clinically effective dose
• Stability: Peptides can be unstable and degrade when exposed to light, heat, or oxygen. Look for products in opaque, airless packaging
• Penetration: The peptide must be able to reach its target cells. Lipophilic peptides (those attached to fatty acid chains, like palmitoyl peptides) penetrate more effectively than hydrophilic ones
• pH: The formulation pH affects both peptide stability and skin penetration

Where Peptides Fit in Your Routine

For optimal results, incorporate peptides into your skincare routine as follows:

1. Cleanse
2. Actives: Apply any acids (AHA, BHA), vitamin C, or retinoids first (if using)
3. Peptide serum: Apply your peptide product on clean skin or over water-based actives
4. Moisturiser: Seal in the peptide serum with a moisturiser
5. SPF: Apply sunscreen as the final step in your morning routine

Peptide Compatibility with Other Ingredients

• Compatible with: Hyaluronic acid, niacinamide, ceramides, vitamin C (L-ascorbic acid at moderate concentrations), retinol (apply at different times of day for best results)
• Use with caution: Strong AHAs and BHAs at high concentrations (low pH can denature some peptides); copper peptides should not be combined with vitamin C or AHAs, as these can reduce copper to a form that generates free radicals

Peptides vs Other Anti-Ageing Ingredients

Peptides vs Retinoids

Retinoids remain the gold standard for anti-ageing, with the strongest evidence base. Peptides are less potent but significantly better tolerated, making them an excellent option for patients who cannot use retinoids (sensitive skin, rosacea, pregnancy) or as a complementary ingredient alongside low-dose retinoids.

Peptides vs Vitamin C

Vitamin C is primarily an antioxidant and brightening agent, while peptides primarily stimulate collagen and modulate cellular function. They address different aspects of skin ageing and work well together. Vitamin C protects existing collagen from free radical damage while peptides stimulate new collagen production.

Professional Peptide Treatments

Beyond topical application, peptides are increasingly used in professional aesthetic treatments:

• Mesotherapy with peptide cocktails: Direct injection of peptide solutions into the dermis for enhanced bioavailability
• Microneedling with peptide serums: The micro-channels created by needling allow peptides to penetrate deeper than topical application alone
• Professional-grade peptide peels: Combining peptides with gentle exfoliating agents for simultaneous renewal and repair

At Axiom Aesthetics, we incorporate evidence-based peptide protocols into our treatment plans where appropriate, using professional-grade formulations that deliver clinically meaningful concentrations.

Frequently Asked Questions

How long does it take to see results from peptide skincare?

Most clinical studies showing significant results with topical peptides used treatment periods of 4-12 weeks. Signal peptides (collagen-stimulating) typically require 8-12 weeks of consistent, twice-daily use to produce visible improvements in firmness and fine lines. Neuropeptides like Argireline may show effects on expression lines within 2-4 weeks. Copper peptides can improve skin tone and texture within 4-6 weeks. Consistency is essential — sporadic use will not produce meaningful results.

Are expensive peptide products worth the cost?

Price does not always correlate with efficacy, but there is a baseline investment required for a genuinely effective peptide product. Producing stable, bioavailable, clinically dosed peptide formulations is expensive, and products priced under £20-30 are unlikely to contain meaningful concentrations of active peptides. However, the most expensive products are not necessarily the best. Look for products that list specific peptide names and concentrations, are backed by clinical data, use appropriate packaging (opaque, airless), and come from brands with a track record in peptide research.

Can peptides replace Botox or fillers?

No. While peptides can meaningfully improve skin quality, firmness, and fine lines, they cannot replicate the effects of injectable treatments. Neuropeptides provide a modest softening of expression lines but cannot produce the muscle relaxation achieved by botulinum toxin. Signal peptides stimulate collagen production but cannot replace the immediate volumising effect of dermal fillers. Peptides are best viewed as complementary to professional treatments — they maintain and enhance results between appointments. Think of peptides as daily maintenance and injectables as periodic interventions.

Are peptides safe during pregnancy?

Most topical peptides are considered safe during pregnancy, as they do not penetrate systemically in significant amounts. However, copper peptides should be used with caution, as copper in excess can be harmful. As with any skincare ingredient during pregnancy, we recommend consulting your midwife or obstetrician. Peptides represent one of the safest active skincare options for pregnant patients who cannot use retinoids, certain acids, or other restricted ingredients.

Can I use peptides if I have sensitive or reactive skin?

Peptides are generally excellent for sensitive skin. Unlike retinoids and acids, peptides do not cause irritation, peeling, or sensitivity in most patients. Signal peptides and copper peptides can actually improve skin barrier function, making them therapeutic for reactive skin. The exception is if you have a known allergy to a specific peptide source or if the product contains other irritating ingredients alongside the peptides. Always patch test new products, particularly if your skin is reactive. Our team at Axiom Aesthetics can recommend suitable peptide products for sensitive skin types.