Peptides are extremely important biological molecules. So, what are peptides? Quite simply peptides are composed of amino acids (basic building blocks of proteins) joined together by special covalent bonds. Peptides are considered ‘pieces of protein’ range from one amino acid to over 50 amino acids. They are responsible for important chemical reactions in the body including:
- Hormones which have a specific regulatory effect on the activity of certain cells or a certain organs
- Receptors for transport of molecules into and out of cells
- Enzymes to speed up chemical reactions in cells
Peptides first entered the skin care arena in the 1980’s with the introduction of GHK copper peptides. This crude, natural peptide exhibited favourable effects for wound healing but this cosmeceutical is now considered basic in its functions. Other basic natural peptides include natural extracts of milk, wheat and certain botanicals.
Peptide technology has evolved significantly over the last 35 years with the advent of the next generation of laboratory synthesised amino acid chains with specific activation targets and functions. Argirilene, released in 2002, was one of the first laboratory synthesised peptides. This small peptide was able to reach the skin dermis to specifically target the cell receptors for acetyl choline. This inhibits muscle stimulation in a similar fashion to Botox™ to soften lines of movement such as smile lines and crow’s feet. There have been many attempts to copy Argirilene over the last ten years; however none directly affect the acetyl choline receptor, until the development of Snap-8™. This is an upgraded version of Argirilene™ which is a slightly longer and more stable molecule.
One of the latest innovations in laboratory engineered peptide technology involves harnessing combinatorial chemistry. This is simply creating a chemical library using the millions of combinations of peptides. Combinatorial chemistry was originally used for pharmacology and medical research, but has now been extended to the manufacturing of cosmeceuticals.
To illustrate this process, suppose we want to manufacture a six amino acid peptide (hexapeptide) to stimulate the production of Type 1 Collagen. Using the 20 naturally occurring amino acids, there are exactly 64 million combinations of these amino acids.
An example of this process is as follows:
1. Define the target e.g. Create a peptide that will increase the synthesis of Type 1 Collagen
2. Attempt to stimulate the gene for Collagen Type 1 synthesis using the peptide sequencing method
3. Perform a screening test using the 64 million peptide combinations.
- 70 out of 64 million hexapeptides stimulate the gene for Type 1 collagen production
- 20 peptides will be chosen for further refinement
- 2 will be shortlisted
- 1 peptide will be selected for commercial production
When it comes to formulating the Synergie Skin products, I refer to my ‘SEED Principle’:
- Stability – The ingredient must not be prone to oxidation or breakdown
- Effectiveness – The ingredient must actually work and have data to support the benefits.
- Elegance –The ingredient must have that ‘feel good’ quality and the customer must want to use it. As well as touch and feel, the product must not have an unpleasant fragrance.
- Delivery – The cosmeceutical active ingredients must be able to reach its target cell to create the desired biological effects.
With that in mind, let’s consider peptides through my SEED priniciple:
Peptides must be stabilised so they do not degrade: Peptides are stabilised in two ways:
- Protective groups (small side molecules) are attached to the peptides to prevent degradation and reactions.
- Nonstandard (Non-Proteinogenic) amino acids are used in the peptide: There are 20 naturally occurring human amino acids in our genetic code .Using the nonstandard amino acids which are not used by the body to make proteins, makes the peptide more difficult to recognise by human protein-degrading enzymes (proteases)
There are literally millions of different combinations of naturally occurring or laboratory synthesised peptides. Peptides are highly specific in their action and perform a huge variety of effects. They may act as enzymes, hormones or cell transporters. As far as cosmeceuticals are concerned, some peptides may stimulate collagen whilst others may reduce oil production, reduce pigment or stimulate production of hyaluronic acid. The effectiveness is related to how the peptides product the desired affects both ‘in vitro’ and ‘in vivo’ when tested for their activity on cells. Clinical data must always support the effectiveness of specific cosmeceutical peptides.
Peptides from reputable suppliers are stringently tested before release to the open market. There is minimal risk of reaction to peptides and they are generally considered non-irritating, odorless and soluble in water. Hence, most peptides are cosmetically elegant when added to both serum and lotion based formulations.
The delivery system of peptides depends on a number of complex factors. The target cells of the skin must be considered in relation to the actual cosmeceutical molecule and the following factors should be considered:
- Molecular weight. The peptide should weigh less than 1000 Daltons. Generally a peptide of less than 10 amino acids is small enough to penetrate the skin. Endothelial Growth Factor, for example, is composed of 53 amino acids and is considered too large to penetrate skin.
- Attaching Palmitic acid to the peptide may aid delivery as this makes the peptide more oil soluble and thus able to travel through lipid layers of the skin.
- Encapsulation of the peptide may improve delivery. Some peptides are laboratory encapsulated and some may be naturally encapsulated. Bilayer encapsulation is suitable for the target cells in the outer stratum corneum. Monolayers are best suited to dermal penetration and new Multilayer (Babashka doll) encapsulation allows different molecules to be delivered to multiple layers of the skin.
Just as Retinol Molecular™, Niacinamide and L-ascorbic acid must adhere to my SEED principle, so too must peptide technology. It is not just a matter of throwing together a few ingredients and expecting them to change the skin. Formulating is an exacting and complex science that must methodically applied and clearly understood. Having an appreciation of the crucial role that peptide technology now plays in formulating effective cosmeceuticals will help consumers make valid choices regarding the products they purchase.