The words like “deep penetration”, “cellular repair” and “target delivery” have been popping up when talking about skincare. Brands have been advertising retinol and vitamin C, peptides and niacinamides can easily and effortlessly travel through this skin. But is it true and does it actually work; does it actually penetrate the skin or just sit on the surface. Some of the top cosmetic science colleges in Nashik train students to better-understand the concept of skin penetration when formulating new skincare products.
So, to make a diagnosis we first need to understand the science of skin penetration which is an interesting blend of biology, chemistry and cosmetic formulation.
Let’s Understand the Skin Barrier
The skin is not exactly absorbent; its primary function is to protect and be waterproof; it’s the first line of defence when it comes to immunity.
The skin has 3 major layers: the epidermis, dermis and hypodermis, the layer of epidermis and stratum corneum. The layer can be described by the “Brick and Mortar” model. Brick: the dead skin layer and Morter: lipid. This structure of the skin only allows specific molecules to pass through the skin barrier.
What Exactly is Skin Penetration?
It is the movement of substances from the surface of the skin into deeper layers. In terms of cosmetics, we can categorise it into three layers.
Surface action: The ingredients remain on the surface the stratum corneum like moisturisers and sunscreens.
Penetration: Ingredients enter the epidermis
Absorption: Ingredients that enter the dermis and can also enter the circulatory system
But the main aim of cosmetics is to penetrate until the dermis and not enter the circulatory system, most cosmetics are designed for topical use and are safe.
Let’s Understand the Various Routes of Skin Penetration
As seen before, not all ingredients can penetrate the skin, there are several factors responsible for influencing penetration efficiency:
1. Molecular Size and the 500 Dalton Rule: there is a rule called the “500 Dalton Rule” i.e. the molecules greater than or larger than 500 Daltons don’t actually pass through the stratum corneum. Ingredients like hyaluronic acid that have higher molecular weight are mostly used for surface hydration. Lower molecular great ingredients can have better penetration.
2. Solubility and Lipid Affinity: generally speaking, the ingredients that are lipid affiliated can easily pass through the skin barrier, ingredients that are water soluble generally on the surface unless designed specifically.
3. Concentration Gradient: having a higher concentration gradient increases the chances for penetration, but only up to a safe limit.
4. Skin Condition: Damaged skin absorbs more; hydrated skin allows better penetration than dry skin.
5. Type of formulation: what is active is added to play an important role in penetration. Actives can behave differently when added to different formulations.
What Exactly is Skin Penetration?
So, what exactly is the role of formulation in enhancing skin penetration?
This is where science and cosmetic scientists play a crucial role. Active ingredients are not lone players; the vehicle that is used to deliver the active is the most important.
There are certain ingredients called penetration enhancers like propylene glycol, ethanol, and certain fatty acids that disrupt the skin barrier and hence improve penetration.
The second category is the delivery system like liposomes, niosomes, nanoemulsions and microencapsulation. This helps the actives that are unstable to deliver properly and control the actives release and improves penetration without compromising the safety of the skin.
After learning about this, do these claims like “deep penetration means better result” or “natural ingredients penetrate better” actually make any sense. Not always, some ingredients are better on the surface and either it is natural or synthetic. It’s all about molecular weight. The smaller the better.
Safety Protocols in Cosmetic Science
Cosmetics are strictly regulated to ensure consumer safety. It is not supposed to penetrate till the circulatory system. That level of penetration requires pharmaceutical clearance and testing.
Conclusion
So, the answer to our question that ingredients actually penetrate the skin is yes, it does penetrate the skin. But as we have seen before, it’s very selective and scientific, only specific molecules and that too under ideal conditions and vehicles can actually penetrate the skin effectively. Pursuing a B.Sc Cosmetic Science program can help you become a competent cosmetologist who can understand skin penetration at a scientific level.
Understanding about the skin barrier and the skin penetration actually helps us make the right and informed choice when we choose our skincare. Skincare is never about making big claims, it’s all about sophisticated formulation which is backed up by science. Cosmetic science is all about safety, efficacy and stability.
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