What is transdermal skincare?

It’s increasingly difficult to peer behind the beauty industry’s mask and discern whether its claims and promises are genuine or just over-hyped marketing tools. But behind the ‘miracle’ cures and avant garde technologies sit continual and important research and education that enable skincare practitioners to navigate the murky waters.

And for consumers, while we smother ourselves with lotions and potions, the key question is whether the goodness is actually hitting the mark or merely hovering on the surface of our skin. It’s all very well to have these breakthrough products, but if we can’t deliver them effectively to their intended targets, what’s the point?

While there are products on the market claiming to contain near-miracle ingredients, many can’t deliver ingredients into the epidermis properly. This is because there is a certain formula through which active ingredients work in synergy with the skin, and many products may have less than what is required for results.

Transdermal products have the ability to store in the voids of the skin for hours, allowing cells to draw off the nutrients as needed. This also means they are working at a cellular level, not just topically. As skin is our largest organ – and a direct route to our circulatory system – it makes sense that this is the most effective surface via which to deliver nutrients and vitamins.

‘Transdermal delivery systems simply give you more bang for your cosmeceutical buck,’ says Terri Vinson, founder and cosmetic chemist at Synergie Skin. ‘Cosmeceuticals that are challenging to penetrate the skin and reach the target cells are now able to create the desired biological effect. The technology involves a number of methods including:

1. Creating channels from physical trauma such as needling used in collagen induction therapy or skin needling

2. Creating thermal channels from treatments such as fractional laser

3. Creating electrically stimulated channels through ionic shift in cells via galvanic systems

4. Creating penetration through specific sound waves via sonophoresis.

Transdermal delivery is no new premise, having been a technology more commonly linked to the pharmaceutical industry for decades. It is now used increasingly within the cosmetics industry to deliver the active ingredient to treat a range of concerns such as cellulite and wrinkles.

Vitamin C is a powerful antioxidant that signifies a major breakthrough in transdermal technology. Around 1990, pharmacologists became aware that L-ascorbic acid could be delivered to the dermis where it was needed most. This breakthrough was in developing transdermal vehicles that stabilised the Vitamin C and ensured its pathway to target fibroblasts.

‘Dr Des Fernandes was one of the pioneers in creating technology to optimise transdermal delivery. His research includes developments in CIT, ionic and sonic penetration,’ says Vinson.

What is transdermal delivery?

Transdermal delivery involves the movement of substances (drugs, vitamins, nutrients, lipids) across the stratum corneum into the systemic circulation (blood). Elliot Isaacs, founder of Medik8 says: ‘As the Medik8 adage goes, ‘there is no point having a magic bullet, if there’s no gun to fire it’. Both standard actives and the latest expensive peptide ingredients are only as good as the delivery system used to introduce them to the deeper skin layers. More often than not, these hi-tech substrates merely sit on the epithelial surface, with only a fraction reaching the target area in the lower epidermal, dermal and hypodermal layers.’

Simply put, transdermal delivery administers active ingredients via the skin, which is an effective medium for absorption and entrance to the circulatory system. By manipulating the intercellular pathway, larger, more unstable molecules such as ascorbic acid and retinoids can be delivered to deeper epidermal and dermal target cells where they are most needed.

The human skin is a complex and dynamic barrier. Its function is to guard against the penetration of undesirable substances such as exposure to UV rays, environmental pollution and cigarette smoke. Daniel Isaacs, Medik8 Formulation and Development Director, explains the upper layer of the epidermis, called the stratum corneum, is made up of 15-20 layers of corneocytes (flattened, dead skin cells) in an alternating arrangement with an intercellular lipid membrane between the cells. This membrane is made up of ceramides, cholesterol and fatty acids and provides a permeability barrier for anything trying to enter the skin. Most molecules will have to use the intercellular route, through the lipid bilayers, just to enter the first layer of the skin.

‘While this is useful for stopping pathogens and disease, this barrier can hinder topically applied skincare actives on their journey into the lower layers of the skin. Transdermal delivery systems are often used in skincare to help enhance the penetration of actives to reach the dermis,’ says Daniel Isaacs. ‘As scientists, we need to devise methods of disrupting the barrier to enable penetration without damaging the barrier and causing inflammation and microbial infiltration,’ says Terri Vinson.

US dermatologist Dr Ronald L Moy, founder of DNA Renewal skincare range adds: ‘In skincare the major breakthrough has been the use of liposomes for delivery of topical anesthetics and our DNA repair enzymes. Tape stripping, peels, ultrasound or facials can all enhance transdermal penetration. We use our gentle glycolic acid-based cleanser to enhance transdermal delivery of our DNA repair enzyme.’

Dermal therapist Vita Catanzariti from Coastal Plastic Surgery & MediSpa says, ‘Transdermal Delivery system in skincare has changed over time and continues to improve. Expanding the use of techniques with molecules, liposomes, nanoparticles and gels and micro emulsions delivers a greater improvement in chemical penetration with less irritation to the skin, better stability and better absorption.’

There is a range of methods using energy waves or pulses to increase product flux across the skin by either the skin barrier (primarily the stratum corneum) or increasing the energy of the product itself. There are two schools of thought on how this process works. One says it uses synthetic liposomes to encapsulate the nutrient and penetrate the skin, which is essentially a lipid bi-layer. Another claims it relies on natural oils to carry the nutrient and penetrate the skin to enter the blood stream.

What are the benefits?

So what are the tangible advantages of transdermal delivery? Besides being a controlled method, it sidesteps the various consequences of traditional administration methods such as first-pass metabolism, whereby the bioavailability of the active ingredients is reduced once it enters the systemic circulation. Using transdermal delivery, this breakdown is reduced as it bypasses the digestive system, requiring a lower dose as a result. It is also local, meaning specific areas such as the eye contour – which is prone to wrinkles and fine lines as we age – can be targeted.

‘The advantage of transdermal delivery of active ingredients like DNA repair enzymes, is deep penetration without the use of needles or microneedling or facials,’ says Dr Moy. ‘Transdermal delivery systems are an important part of our skincare, because the DNA repair enzymes are delivered transdermally via liposomes (fat particles protecting the enzymes), allowing deep penetration of these active ingredients into the deep dermis,’ he says. ‘Studies have shown a deep transdermal penetration of these DNA repair enzymes using liposomes. Along with our skincare range, we also use a mask that enhances transdermal delivery of DNA repair enzymes into the skin.’

‘Transdermal delivery enables results that were previously difficult to reach. Larger molecules such as hyaluronic acid are unable to penetrate the skin barrier due to their high molecular weight; however transdermal systems optimise penetration and enable a deeper hydration of the skin,’ says Vinson.

‘Medik8 uses penetration enhancers in the form of encapsulation of active ingredients. Transdermal delivery via encapsulation not only helps the penetration of actives into the skin, delivering them further into the skin layers, but also protects the active ingredient from the external environment,’ says Daniel Isaacs. ‘With the skin regarded as the impeccable external protective barrier of our body, even those who may be sceptical of the true efficacy of transdermal delivery must be impressed with the scientific evidence,’ he says.

Vinson says numerous methods can quantify the efficacy of transdermal delivery, including ‘before’ and ‘after’ photos in controlled scientific conditions quantifying the specific effect of the cosmeceutical such as reduction in pigmentation, reduction in fine lines and wrinkles, and increase in skin hydration. ‘There are good studies with DNA repair enzymes using immuno-florescent tags to document deep penetration,’ adds Dr Moy. ‘What results can usually be seen? The most important factor judging the efficacy is how effectively the active ingredients such as DNA repair enzymes prevent skin cancers, treat pre-skin cancers and most importantly make the skin more beautiful. We have studies using our skincare line that prove we can improve eye bags, acne scars and tighten neck skin with our transdermal delivery of our active ingredients.’

Daniel Isaacs says in vitro methods will use skin biopsies or skin models to characterise the penetration of particular actives, usually utilising fluorescent markers. In vivo studies can compare the results of an encapsulated form of an active to the normal unencapsulated form of the active. ‘Medik8’s r-Retinoate uses a unique encapsulated form of retinol retinoate in biodegradable polylactic acid (PLA). The results of this has been found to greatly increase penetration of retinyl retinoate through in vitro and in vivo studies published in Skin Research & Technology,’ says Daniel Isaacs.