Understand the Structure of the Skin and Its Relationship with Cosmetics
The skin is the largest organ of the human body and plays a vital role in protection, regulation, and sensory perception. To understand how cosmetic ingredients work, it is essential to know the layers of the skin: epidermis, dermis, and hypodermis. In this article, we explain their structure, functions, and how they interact with cosmetic products.Why Is It Important to Understand the Layers of the Skin in Cosmetics?
When developing and applying cosmetic products, understanding the anatomy of the skin helps in selecting the most effective ingredients. Each layer has specific characteristics that determine the penetration, absorption, and efficacy of cosmetic actives.Epidermis: The Protective Barrier
The epidermis is the outermost layer of the skin. It acts as a barrier against external aggressors such as bacteria, UV radiation, and pollutants. It consists of several sublayers, including:- Stratum corneum: where dead cells accumulate; it is key for protection.
- Basal layer: where new cells are generated and melanin is produced.
Main Functions of the Epidermis:
- Protection from the environment
- Prevention of water loss
- Production of keratin and melanin
Cosmetic Ingredients That Act on the Epidermis:
- Moisturizers (high molecular weight hyaluronic acid)
- Gentle exfoliants (AHAs, BHAs)
- Sunscreens
Dermis: The Middle Layer That Provides Firmness
The dermis lies beneath the epidermis and is where the skin’s support structure is found. It contains collagen, elastin, blood vessels, and nerve endings.Main Functions of the Dermis:
- Structural support and elasticity
- Thermal regulation
- Nutrient supply to the epidermis
Cosmetic Ingredients That Act on the Dermis:
- Peptides
- Retinoids
- Low molecular weight hyaluronic acid
- Growth factors
These ingredients require formulations that can penetrate beyond the epidermis to stimulate collagen production and improve firmness.
Hypodermis: The Deepest Layer
The hypodermis, or subcutaneous tissue, is composed mainly of fat and connective tissue. Its role is to protect internal organs, act as an energy reserve, and assist in thermal insulation.Main Functions of the Hypodermis:
- Mechanical protection
- Energy storage (fat)
- Temperature regulation
Although most cosmetic products do not directly reach this layer, advanced aesthetic treatments (such as mesotherapy or device-based therapies) can have an impact on the hypodermis.
How to Choose Cosmetic Ingredients According to Skin Layers
When formulating a cosmetic product, it is crucial to consider which skin layer it is intended to target. For example:- To hydrate the surface: use large molecular size ingredients (like glycerin or panthenol).
- To treat wrinkles and firmness loss: use smaller molecules like retinol or peptides, which can reach the dermis.