How peptides work in cosmeceuicals

What are peptides?

In the personal care industry, the term ‘peptide’ refers to molecules that are short chain amino acids – very small substances – that are able to traverse to the stratum basale and signal physiological changes at the dermal level; or in some cases, effectively travel into the dermis and compete with neurotransmitter binding sites to temporarily alter a physiological activity. 

Why do some products work better than others?

One of the biggest challenges a Cosmetic Chemist always faces is delivery of an active to the required site. To pass through the stratum corneum (and deeper layers) substances either need to pass through the cells or around them (the intercorneocyte space). Water soluble substances need to be extremely small to traverse the stratum corneum. Lipid soluble substances can travel through lipid bilayers when small, but still have similar distances to travel. Even if they can enter a pathway, they then have an incredibly large distance to travel (compared to their size) to penetrate beyond the stratum corneum!

This is particularly important with the delivery of peptides – they are extremely small and can traverse to the stratum basale and beyond; but compared to their size, they need to travel an incredibly HUGE distance – so the vehicle, the product base they are in, becomes an essential component to enable the bulk of their passage through the epidermis. Once they are ‘delivered’ to the stratum basale, their ability to travel into the dermis and make a difference is certain – but getting them there is the hard part!

Standard emulsions are amphiphilic bases, containing both hydrophilic (water) and hydrophobic (lipid) phases as well as amphiphilic substances (the emulsifiers), so act as excellent delivery vehicles for small substances to at least the deeper layers of the stratum corneum. The use of osmolytic substances such as humectants can enable penetration to the stratum granulosum level. To provide the required activity, peptides must be provided to the skin in a suitable carrier base to reach the stratum basale target site - this is usually best achieved using an emulsion (amphiphilic) base combined with humectant agents and/or liposomal delivery agents.

Using key materials to ensure delivery of these actives to the stratum basale will give a competitor product a leading edge over another brand using the same active in the same proportion but in a poor delivery base. This comes down to clever formulating to ensure the best possible visible results for a consumer.

Finally, don’t think that appearing low on an ingredient list means there isn’t much of this substance present – on the contrary, and particularly with peptides – it is because these substances are so small that not much is needed to get the great results. As little as 77mcg is all that is clinically required, per application, to get the amazing results with the hexapeptide I mentioned in this report – some other peptides are required in even smaller quantities for other skin or hair benefits!