How can peptides be used in cosmetics?

The peptides are able to influence numerous biological mechanisms within the skin. Depending on their structure and the amino acids they contain, some peptides stimulate the production of collagen and elastin, contributing to skin firming and reducing the appearance of wrinkles, whilst others exhibit antioxidant properties that protect cells from oxidative stress. Some peptides also encourage healing and regeneration of the epidermis, reinforce the skin barrier to better retain moisture and enhance hydration, or soothe inflammation and sensations of tightness. This diversity of actions explains why peptides are now increasingly employed in cosmetic formulations.

How are peptides used on the skin?

Integrating peptides into a facial skincare routine primarily depends on the type of product in which they are formulated. As with any active ingredient, it is essential to follow the supplier’s recommendations. Found in serums, creams, eye-contour products or masks, peptides are generally applied to clean skin, before or after moisturiser depending on the product’s texture. Peptides are not photosensitising: they can therefore be used both morning and evening, and present no contraindications when used alongside other actives such as hyaluronic acid, niacinamide or ceramides, nor are there any contraindications during pregnancy or breastfeeding. Daily application, morning and evening, enhances their effectiveness.

Peptides are also highly promising for hair. Some studies suggest they may stimulate the proliferation of hair follicle cells and activate the Wnt/β-catenin and GSK-3β/β-catenin biological pathways involved in the hair growth cycle. Peptides are also believed to boost the expression of growth factors such as IGF-1 and VEGF, essential for proper follicle function. However, caution is warranted: most of these observations stem from studies in vitro, and their actual efficacy in promoting hair growth still needs confirmation. Their role in repairing the hair fibre is better documented. Peptides, especially those derived from collagen, help strengthen keratin, smooth the cuticle, and improve hair elasticity and shine.

How are peptides utilised in hair applications?

As with skin, the use of peptides in hair care depends on the type of product selected. Leave-in serums and lotions are applied directly to a clean scalp, gently massaging to encourage penetration, while peptide-enriched masks and conditioners are used after washing, with contact time adjusted according to the formulation. Peptide-based shampoos also exist, which are used like a shampoo in the usual way. However, if their purpose is to promote hair growth, we recommend that you leave it on for a few minutes, to allow the active ingredients time to penetrate the scalp.

Oral peptides, particularly collagen peptides, are now extensively studied for their effects on the skin. Several clinical trials have shown that regular supplementation with collagen peptides significantly improves hydration, elasticity and skin barrier function, whilst reducing roughness and wrinkle depth. These effects rely on the stimulation of endogenous collagen and hyaluronic acid synthesis, as well as on improved organisation of collagen fibres in the dermis. Ingested peptides also exert antioxidant and anti-inflammatory actions, helping to protect the skin from oxidative stress and UV-induced damage, two mechanisms central to skin ageing.

How are peptides administered orally?

The administration protocol for oral peptides depends on the type of supplement selected, but most clinical studies use a daily dose of 2.5 to 10 g of collagen peptides for at least 8 to 12 weeks to observe visible effects. Supplements are often supplied as powders, capsules or beverages, to be consumed once daily, preferably at a fixed time. Nevertheless, as with any dietary supplement, it is advisable to consult a doctor before beginning supplementation, especially in the presence of a medical condition, during pregnancy or when taking medication, in order to ensure compatibility and safe use.

Injectable peptides are a recent innovation in the field of aesthetic dermatology, particularly when used in synergy with botulinum toxin (botox). Their value lies in their ability to reinforce the effects of neurotoxins while delivering complementary benefits depending on the peptide employed: softening wrinkles, enhancing skin radiance and improving overall skin quality. Peptide injections can also be administered to the scalp to promote hair growth, or even combating alopecia.

How are peptides utilised in injections?

Peptide injections are administered exclusively in a medical practice under the supervision of a qualified professional.

Just as with hyaluronic acid injections, peptide injections are relatively quick and painless, lasting only about ten minutes. They may cause mild redness, swelling or small bruises, which usually resolve within a few days. The number of sessions depends on the desired outcome. To reduce the visibility of wrinkles, 3 to 4 sessions spaced 2 to 3 weeks apart are generally recommended. In cases of alopecia, 5 to 7 sessions may be necessary, initially every two weeks and then monthly. The results emerge gradually, over the course of the sessions, as the peptides exert their biological effects on the tissues.

Note: Peptide injections are not suitable for everyone. Pregnant or breastfeeding women, people with coagulation disorders or an active skin condition, such as acne for instance, cannot benefit from these injections. In any event, prior medical advice is required to ensure the safety and appropriateness of this type of procedure.

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