Topically Applied Collagen

Florence Barrett-Hill
Collagen has been a component of skin care formulations for many years, and over this time there have been numerous claims of its efficiency to directly assist in the treatment of fine lines and wrinkles by supplementing the skins own collagen and assist in the development of new collagen.
In years past, we believed the marketing hype that led us to trust that topically applied collagen had the ability to do this, however these days we are now more aware of the real facts behind this myth.

Collagen
Injection of collagen has been shown to be the only method of delivering effective quantities of this protein below the epidermis

Imagine my surprise when at an international professional beauty expo, I came across a company that was promoting a product that contained bovine collagen as a key ingredient to stimulate new human collagen growth in the dermis.
After listening to the sales pitch of one of the staff on the stand, (who was adamant that the bovine collagen in the formulation helped stimulate new collagen growth via being absorbed through the epidermis) and looking at the rest of the ingredients, it became clear that it was the other ingredients that played the stimulating role in collagen production.
So why was the collagen being peddled as the “wonder ingredient”?
It would seem that there are people who still do not understand why topically applied collagen can not play any role in a formulation other than providing substance to the cream or gel it is used in. 

What about collagen injections?
This is where some folks get a little confused about what introduced (not synthesised by the body) collagen can and can not do.

We know collagen in the body is the primary connective tissue protein and is present in skin and cartilage. Its main physiological functions are to provide structural integrity and tensile strength for connective tissue.
It is now well known that injecting forms of collagen below the epidermis does indeed provide temporary supplementation of the existing collagen before being slowly broken down into amino acids and then absorbed by the body, however this introduced collagen is simply a dermal filler. It does nothing to stimulate the new growth of collagen. Any topical application of collagen will have even less of a role because of a number of its biological and physical properties. Let’s look at the types of collagen found in formualtions, and why it can not stimulate collagen synthesis.

Bovine collagen
Most collagens used in cosmetic formulations are derived from bovine, pig or fish sources

Collagen in formulations
The processed collagens used in cosmetic formulations, shampoos and conditioners are primarily used in for their substantive plumping and humectant (moisturising) properties. Understandably they are water-soluble.

The most common forms of collagen in cosmetic formulations are Collagen hydrolysate (Bovine) and Protein Hydrolysate. (Marine) There are other forms derived from wheat and seaweed that are less common, but for the purposes of this discussion, we will focus on the animal derived collagens.
The term hydrolysate comes from the process of Hydrolysation and refers to enzymatically or chemically processed collagen, which is mainly derived from bovine, ox and pigskin and bone, or in the case of marine collagen, fish scales and bone.

Hydrolysed collagen consists of water-soluble peptides of various molecular weights. These peptides are rich in the amino acids found in collagen, including glycine, L-proline and L-hydroxyproline.
Nutritional supplements containing hydrolysed collagen are marketed for bone and joint health purposes. Hydrolysed collagen and gelatin hydrolysates are similarly used. It is these peptides and amino acids that are the basis of enthusiastic claims.

Collagen
There is insufficient clinical data to prove that toppically appled collagen assists in the synthesis of new collagen in humans

How is it supposed to work?
The claims that Hydrolysed collagen contributes to the synthesis of new collagen is based on the amino acids that it contains; however L-hydroxyproline is not a genetic amino acid. It is formed in collagen post-translationaly. (After formation) Consequently, L-hydroxyproline in hydrolysed collagen would not contribute to collagen synthesis. Further, the body synthesizes both glycine and L-proline, so it is unclear how any glycine or L-proline in hydrolysed collagen would make any significant contribution to further collagen synthesis.

There is speculation however, that some oligopeptides that may be present in hydrolysed collagen may have a stimulatory effect on collagen synthesis, but for this to occur, they must be able to reach the fibroblast. (the cell that initiates collagen production)
Health supplements that aid joint and cartlidge ailments use collagens that are injested with the peptides delivery system to the site of damage via the bloodstream. Similarly, any nutrients delivered to the fibroblast of the dermis must also be via the microcirculation. In this case it is to the papillary layer.

This is where the problem of the topically applied collagens molecular size and how it circumvents the lipid bi-layers of the epidermis for transdermal absorption in to the microcirculation presents itself.

collagen absorption
The epidermal bilayers form the biggest barrier to topical collagen absorption

Size, compatability & quantity
Typically, high quality hydrolysed collagen has a molecular size of around 5,000 9,000 Daltons, (A Dalton is a measure of atomic weight of molecules) whereas a size below 2,000 Daltons is required to penetrate the lipid bi-layers of the epidermis. (Some forms of collagen have molecular sizes up to 300, 000 Daltons!) Further, the introduced collagen is a water-soluble (hydrophilic) protein, and the lipid bi-layers are the epidermis’s oil (hydrophobic) barrier.

The laws of physics demonstrate that water based substances will not penetrate this lipid barrier easily.

Clearly, unless some form of penetration enhancement is utilised, the collagen has little chance of completing its transdermal journey. Further, the sheer quantity of collagen required to make a noticeable contribution over the any given period of application is only practically delivered by volume injection.
Note that injected collagen has not been shown to offer any stimulating activity for the generation of new collagen in the dermis, so there is really no point in persuing technologies that could deliver the peptides of topically applied collagen to the lower levels of the epidermis when there are so many other quality ingredients such as the various forms of vitamins A and C that have been proven to better assist in the stimulation and formation of collagen.

Contemporary therapists are more aware of the limitations of new products and treatments than ever before due to better education. Perhaps the marketing departments of some skin care companies should consider this before making performance claims that we consider outdated and consequently embarrassing.


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