Ceramides and peptides in cosmetics: what do they do?

How do ceramides compare with peptides?

These ingredients address different priorities rather than offering two versions of the same treatment. Moisture retention is the clearer reason to buy a ceramide moisturizer; a peptide product needs a more specific goal. A peptide claim needs a named peptide and a finished formula, because 'peptides' is a category, not a performance review.3

What do ceramides do in skin care?

Your skin barrier is the outer layer that separates your body from the outside world. Ceramides help hold its building blocks together, limit moisture loss and make it harder for irritants and allergens to penetrate. Skin replenishes its natural ceramides less quickly with age, and reduced ceramide levels also occur in eczema. Added ceramides help keep skin hydrated, soft and plump. Common ingredient names include ceramide EOS, ceramide NP and ceramide AP.1

The outermost layer, called the stratum corneum, contains dead skin cells held together by a matrix of fats. Barrier damage allows more water to escape and increases sensitivity to irritants and allergens. Ceramide creams are particularly useful to consider for dry skin; synthetic ceramides are also thought to help manage atopic dermatitis, a form of eczema. A moisturizer supports barrier care rather than replacing medical treatment for persistent symptoms.45

What do peptides do?

Peptides are not interchangeable. Their amino acid sequence affects their shape, charge, interaction with skin targets and movement through the skin's lipid layer. Some are investigated for collagen production, pigmentation, inflammation or barrier function. Collagen is a structural protein that helps give skin its firmness. Those possible uses belong to particular peptides, not automatically to everything sold as a peptide serum.3

Cosmetic peptides are commonly grouped by their intended action:

• Signal peptides aim to influence processes such as production of collagen and other supporting skin proteins.
• Carrier peptides deliver trace elements such as copper or manganese.
• Neurotransmitter inhibitor peptides target chemical signalling between nerves and muscles.
• Enzyme inhibitor peptides target enzyme activity.

Getting a peptide to its target is a major practical obstacle. Many peptides pass poorly through skin, and stability also affects delivery. Formulation research includes encapsulation in tiny delivery systems, such as liposomes, to improve access to the intended site. A sophisticated delivery description still needs to connect to the cosmetic result you want. For wrinkle claims, favour human testing of the finished formula over an impressive ingredient story, even if the story has excellent packaging.3

How long do peptide results take?

Some peptide formulas have improved fine lines in controlled human trials. In one trial involving 93 people, a moisturizer containing 3 parts per million of palmitoyl pentapeptide 4 reduced the appearance of fine lines and wrinkles over 12 weeks compared with a placebo moisturizer. Another trial found reductions in wrinkle depth, volume and roughness after two and four months. These are useful expectations for the tested peptide formulas: gradual cosmetic changes over weeks to months, rather than an immediate lifting effect.2

How should you choose and use a ceramide moisturizer?

1. 1Match the texture to your needs. Dry skin generally benefits from a cream or ointment; a gel feels lighter and is an option for oily skin. For combination skin, concentrate moisturizer on dry areas.
2. 2Look beyond ceramides. Glycerin and hyaluronic acid attract and bind water, while ingredients such as dimethicone help keep moisture in.
3. 3Apply moisturizer to damp skin within three minutes of washing your face or showering.
4. 4For excessively dry skin, choose a moisturizer you can use at least twice daily. Adjust the texture when dryness changes.
5. 5Include broad spectrum sunscreen with SPF 30 or higher in your daytime routine. Moisturizing and targeting wrinkles do not replace sun protection.

Petroleum based barrier products reduce water loss effectively, while dimethicone barrier creams feel less greasy. Pick the texture you will actually use, rather than making your moisturizer a daily negotiation.4

Who should be careful?

For dry or sensitive skin, fragrance and other formula ingredients deserve attention even when ceramides appear on the label. Barrier creams are usually well tolerated, but preservatives, fragrances and other components can cause allergic contact dermatitis, an itchy inflammatory skin reaction. Some occlusive barrier creams can aggravate facial acne, and most should not go directly onto broken skin. Do not exfoliate dry, peeling skin in an attempt to remove the problem; moisturize instead.45

Seek a dermatologist's help if dryness does not improve with moisturizing, or becomes painful, cracked, bleeding, stinging or very irritating. Persistent symptoms can require prescription treatment and changes to your routine.5