Hair fibres: the complete guide to thickening your hair

Key takeaways

• Hair fibres are 0.3 to 0.5 mm microfibres that cling to your existing hair through an electrostatic charge and visually thicken the hair in seconds.
• Two materials dominate the market: cotton cellulose (natural and vegan, like Ecobell) and keratin (close to the hair’s own fibre, like K-Max).
• They camouflage early baldness, a widened parting, temples and roots — but they need existing hair, even fine hair, to cling to.
• The result lasts until you shampoo, and longer with a fixing spray.

You come across the term everywhere — bottles, tutorials, forums — without always knowing what it covers: hair fibres are today the fastest cosmetic solution for restoring density to thinning hair. Not a treatment, not a transplant, not a colouring: instant camouflage, reversible with your first shampoo. Here is how they work, how to choose between the materials, and how to apply them for a truly undetectable result.

What exactly is a hair fibre?

A hair fibre (also called microfibre or hair powder) is a fragment of material cut to a microscopic size — 0.3 to 0.5 mm for the most precise manufacturing, done by laser. These fibres are dyed through, then coated to maximise their electrostatic charge.

This charge is what does it all: like tiny magnets, the fibres grip onto existing hair and down. Each hair ends up surrounded by dozens of microfibres in its colour — it looks thicker, and the hair mass immediately seems denser. The scalp, less visible through the hair, stops giving away the thinning areas.

An important consequence: the fibres need a support. On a completely smooth area, without hair or down, they have nothing to cling to — you then need to turn to a hair mascara, which colours the skin directly.

Cotton cellulose or keratin: which material to choose?

Two families of fibres share the market, and we distribute both — here is how to decide.

Cotton cellulose fibres

Ecobell powders are made from laser-cut cotton cellulose: 99.6% natural in origin, 100% vegan and free of animal-derived ingredients. It is the choice for sensitive scalps and for those who want a minimalist composition. The finish is matte and light, with no heavy build-up.

Keratin fibres

K-Max powders use keratin microfibres, the protein that naturally makes up hair. The material affinity favours a visual fusion with the existing fibre. It is the market’s historic approach, that of the reference Italian and American brands.

In both cases, the grip is purely electrostatic: no glue, no greasy residue, and complete removal with shampoo. The difference lies in the composition (vegan or of animal origin), your scalp’s sensitivity and your finish preference — not in camouflage effectiveness, which is equivalent. For a detailed comparison of the two materials, read Keratin fibres or cotton cellulose: which to choose? — and to place the brands against each other, our thickening powder comparison.

Who and what for: the uses of hair fibres

The fibres suit men and women alike, on all hair types — straight, curly, coily, short or long. The situations where they excel:

• Early baldness: receding temples, a thinning crown — the fibres delay the moment when “it shows”.
• Female thinning hair: a widening parting, diffuse or post-partum density loss, a ponytail that thins the hairline.
• Roots and scars: white roots between two colourings, scars from old procedures, localised patches.
• A complement to an anti-hair-loss treatment: during the months a treatment takes effect, the fibres handle the visual side day to day.

How to apply a hair fibre powder?

Always on washed, styled and perfectly dry hair — never damp, or the fibres will spread poorly.

1. Sprinkle the bottle over the thinning areas, a few centimetres from the hair.
2. Pat lightly with your hand to distribute the fibres and work them down between the hairs.
3. Fix with a gas-free fixing spray: the hold goes from one day to several days, and resists wind, light rain and perspiration.

To gain precision, two accessories change the game: the applicator spray, which sprays the fibres evenly while saving powder, and the hairline comb, which draws a clean edge on the forehead. A multi-panel mirror helps check the crown, otherwise invisible.

How much does it cost, and where to buy?

Expect around ten euros for a small entry-level bottle and €25 to €35 for a quality 25 g bottle, i.e. one to two months of daily use. The real savings lever is the refill: a 100 g sachet brings the price per gram down to a fraction of the bottle’s, and cuts packaging waste.

In pharmacies, the offer is often limited to one brand in a single format, sold at a higher price per gram than online. By buying from a specialist shop, you get access to refill formats, the full range of shades — nine at Ecobell, blendable with each other to create your exact tone — and application accessories.

Frequently asked questions about hair fibres

Can you see hair fibres?

No, provided you choose the right shade: the fibres blend with your hair and the finish is matte, with no artificial sheen. If hesitating between two shades, take the darker one for the mass and the lighter one as a finishing touch on the hairline.

How long do they last?

All day in normal conditions, several days with a fixing spray. They wash out completely with shampoo.

Do the fibres damage hair or prevent regrowth?

No: they stay on the surface, do not clog pores and do not interfere with the hair’s natural growth. They wash out entirely.

Can they be used with a treatment like minoxidil?

Yes: apply the treatment to a dry scalp, let it absorb completely, then apply the fibres. They do not interfere with absorption.