Mechanical beauty: invisible aging

Have you ever heard of mechanical beauty?

Mechanical beauty is a scientific approach to beauty that focuses on protecting the skin and hair by reducing daily physical stress rather than simply adding more and more active ingredients.

Indeed, modern cosmetics talk about active ingredients.

Dermatology talks about inflammation.

Trichology talks about keratin.

But there is one overarching factor that links it all: mechanics.

Friction, compression, shearing, traction – these invisible physical forces influence the condition of the skin and hair on a daily basis.

This comprehensive guide explains:

• What mechanical stress is
• How it accelerates skin ageing
• Why it weakens the hair
• How to reduce it scientifically
• And why the textile environment plays a key role

Welcome to the scientific understanding of mechanical beauty.

In cutaneous biophysics, mechanical stress refers to a physical force applied to tissues.

We distinguish between:

• Friction: the force of rubbing between two surfaces
• Shear: lateral slippage of tissue layers
• Compression: prolonged pressure
• Tension: stress exerted on fibres

These repeated stresses can cause micro-inflammation, damage to collagen fibres, disruption of the hydrolipidic film, and lifting of the hair cuticles.

It is not the occasional intensity that causes damage. It is chronic repetition.

Sleep lines are creases caused by prolonged pressure during the night.

For 6 to 8 hours:

• The skin is compressed;
• the tissues are subjected to shear forces;
• the creases always form in the same places.

With age, the loss of elasticity makes these creases less reversible. The areas most affected are: the cheekbones, the eye area, and the nasolabial folds.

Mechanical repetition encourages their formation.

Friction can:

• Damage the skin barrier: Friction exerts shear forces on the skin’s surface, which can disrupt the organisation of lipids and weaken the cohesion of cells in the stratum corneum. When repeated, it can increase transepidermal water loss (TEWL), exacerbate dehydration and make the skin more sensitive. This chronic mechanical stress gradually weakens the skin barrier and contributes to premature ageing.
• Increase transepidermal water loss (TEWL): Transepidermal water loss (TEWL) refers to the natural evaporation of water through the skin. When the skin barrier is weakened, particularly by repeated rubbing, its ability to retain water decreases. The skin then allows more moisture to escape. In the long term, this increase in TEWL promotes dehydration, loss of suppleness and the more pronounced appearance of fine lines.
• Increased sensitivity: Repeated friction stimulates superficial nerve endings and can weaken the skin barrier. When the skin barrier is compromised, the skin becomes more permeable and reacts more strongly to external aggressors (pollution, temperature fluctuations, cosmetic ingredients). Over time, this mechanical stress can increase skin sensitivity, leading to more frequent redness, discomfort or a tight, pulling sensation.

Rough fabrics increase the coefficient of friction. Smooth surfaces reduce it.

The hair shaft is composed mainly of keratin and is organised into three layers: the medulla (at the centre), the cortex (inner structure) and the cuticle (outer layer).

The cuticle is made up of fine, transparent scales, overlapping one another like tiles on a roof. This structure protects the cortex, maintains internal moisture and ensures the hair’s shine by reflecting light.

When these cuticles are smooth and well-aligned, the hair is supple, shiny and strong. When they lift or become damaged (due to friction, heat or chemical treatments), the hair fibre becomes more porous, more fragile and prone to breakage.

Repeated friction:

• Lifts the cuticles
• Increases porosity
• Weakens keratin cohesion

Results:

✔ Breakage

✔ Frizz

✔ Split ends

✔ Loss of shine

Night-time is a critical phase due to repeated unconscious movements.

The fabric has a direct influence on:

• The coefficient of friction: The fabric influences the coefficient of friction, i.e. the resistance to sliding between the skin (or hair) and the surface. A rough fabric increases friction and mechanical stress. A smooth surface reduces these and limits micro-trauma.
• The pressure exerted: The fabric influences the distribution of pressure exerted on the skin during sleep. A stiff or inflexible fabric can accentuate pressure points, whilst a softer, more adaptable surface distributes pressure more effectively. Prolonged, localised pressure promotes skin creasing and mechanical stress on the tissues.
• Moisture management: A highly absorbent fabric can draw out some of the skin’s natural moisture, whilst a less absorbent fabric helps to preserve it. Poor moisture regulation can lead to skin dehydration and weakening of the hair fibre.

An absorbent and rough fabric therefore increases shear forces, dehydration and hair fibre stress.

According to Regulation (EC) No 1223/2009, a cosmetic product is defined by its function:

To come into contact with the external parts of the human body in order to protect them or keep them in good condition.

The definition is based on the functional effect.

A textile that remains in prolonged contact with the skin, exerting a mechanical influence on it and reducing physical stress, can be seen as part of this protective approach.

Certain brands specialising in silk, such as Les Laboratoires SILKBIOTIC, are developing this preventive approach by acting on the coefficient of friction and limiting nocturnal micro-trauma.

It is not a question of adding an active ingredient. It is a question of reducing irritation.

For the skin

✔ Choose smooth surfaces

✔ Avoid rough fabrics

✔ Minimise prolonged pressure

For the hair

✔ Avoid tying it too tightly

✔ Minimise friction whilst sleeping

✔ Preserve natural moisture

Anti-ageing prevention is based on three key areas:

1. Chemical protection, which involves the use of active ingredients capable of neutralising biological aggressors. Antioxidants, UV filters and repairing agents help to limit oxidative stress and collagen breakdown. This approach protects the skin against environmental factors responsible for premature ageing.

2. Biological stimulation, i.e. the activation of the skin’s natural mechanisms. Certain active ingredients promote the production of collagen and elastin, or cell renewal. This approach aims to strengthen the skin’s structure and maintain firmness and elasticity over time.

3. Reduction of mechanical stress, i.e. limiting repeated friction, compression and tension. By reducing these daily micro-aggressions, we reduce the stress placed on the skin tissues. Less mechanical stress means fewer repeated creases and better preservation of elasticity over time.

The third pillar is the most underestimated: Less friction = fewer repeated micro-creases = less tissue stress.

The skin and hair are not only subjected to chemical stress. They are also exposed, day and night, to repeated physical stress.

Reducing this mechanical stress represents a scientific, consistent and resolutely preventive approach to beauty.

It is within this context that SILKBIOTIC silk comes into its own. It offers a naturally smooth surface, certified organic, Oeko-Tex and GOTS. It is gentle and helps to limit friction, preserve moisture and protect the hair fibre.

Because beauty depends not only on what we apply, but also on the surface upon which our skin and hair rest.