Hair behaviour - how it absorbs, retains, and loses moisture - is dictated by its structure. At a fibre level, this comes down to the condition of the cuticle, the integrity of the cortex, and the cohesion of the cell membrane complex (CMC).
This is what we define as porosity.
At The O11, formulation starts here - because hair ingredient performance is only as effective as its ability to interact with the fibre correctly.
Low Porosity: Resistant, Intact, Controlled
Low porosity hair is defined by a compact cuticle with an intact lipid layer. Moisture and ingredient diffusion into the fibre is limited, and most ingredients remain on the surface (often resulting in a coated or greasy feeling if too much product is applied).
Formulation Strategy: Precision Surface Engineering For Low Porosity Hair
- Lightweight cationic polymers and silicones align the cuticle without excessive build-up;
- Low molecular weight humectants support controlled hydration without swelling the fibre;
- Lightweight lipids support the natural lipid barrier function.
The goal is not penetration - it is optimised surface performance, maintaining smoothness, slip, and controlled moisture balance.
Medium Porosity: Balanced, Responsive, Adaptive
Medium porosity hair presents a partially open cuticle with moderate CMC integrity. It is the most responsive fibre type - able to both absorb and retain actives effectively.
Formulation Strategy: Dual-Level Functionality
- Film formers + penetrative actives work in synergy;
- Hydrolyzed proteins and peptides reinforce internal structure;
- Balanced lipid systems maintain cohesion without heaviness.
This is where formulation can operate across both surface and cortex - delivering multi-level performance.
High Porosity: Structurally Weak But Easily Penetrated
High porosity hair is characterised by a disrupted cuticle and a degraded CMC. Moisture and ingredients can easily diffuse into the cortex, however retention is poor. The fibre tends to be mechanically fragile.
Formulation Strategy: Internal Reinforcement + Barrier Reconstruction
- Hydrolyzed proteins, peptides, and amino acids penetrate to reinforce the keratin matrix;
- High-affinity cationic polymers bind to damaged sites for targeted repair;
- Ceramides, fatty acids, and cholesterol replenish the CMC, restoring cohesion;
- Occlusive lipids and silicones reduce water loss and protect the fibre.
The objective is twofold: rebuild internal integrity and re-establish the barrier.
Water, Always - But Controlled
Across all porosity types, water remains a critical variable.
- In low porosity hair, excess water disrupts balance;
- In high porosity hair, water is lost too easily;
- In medium porosity hair, water can be optimally regulated.
Humectant systems must therefore be tuned, not maximised.
Formulation, Re-Engineered
Porosity is not a trend - it is a functional framework for understanding hair behaviour.
At The O11, we don’t formulate for “dry” or “damaged” in isolation. We formulate based on how the fibre interacts with ingredients and asking the right questions:
- How open is the structure?
- How intact is the lipid network?
- How well does the cortex retain what it absorbs?
Because real performance comes from placing the right chemistry, in the right place, for the right fibre condition.
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