Repair Protein Hair Mask

Hydrolysed keratin is keratin protein cut into fragments small enough to settle into the porous, worn parts of a damaged hair shaft. It sits there temporarily and stiffens the fibre slightly, which is why protein treatments perform well in swatch testing that measures tensile strength and the force needed to drag a comb through wet hair. The conditioning complex around it is the ordinary and effective part: cationic conditioners and fatty alcohols that lie along the cuticle, flatten it and cut friction between hairs.

On the evidence, this is one of the better understood pieces of cosmetic chemistry in the range, and also one of the most modest. Those measurements are mostly made on hair swatches in a laboratory, and often by the ingredient suppliers who sell the raw material. Independent trials on people are thin on the ground. The effect is physical and temporary, and it washes out over the following few washes, which is why the instruction is once a week for as long as you want the effect. Nothing in this jar reaches a follicle, changes a hair cycle or affects how much hair you grow.

It is the concentrated weekly version of the Repair Protein Conditioner, same chemistry at a higher load and a longer contact time. If your hair is dry, rough, coloured or bleached, or if it snaps when you comb it wet, this is the one worth having. It also earns its place in a hair loss range for a practical reason. A treatment routine means daily washing, alcohol-based topicals on the scalp and, for many men, a Dermaroller and a great deal more handling and inspecting of hair than before, and all of that is hard on the shaft. Pair it with the Deep Cleanse Scalp Shampoo on the same day, since a clarifying wash strips the fibre and this puts something back. If your hair is fine and limp with no real damage to it, the Smoothing Hair Mask is the better choice, because protein on undamaged hair can read as stiff.

Once a week, in place of your conditioner.

1. Shampoo as usual, then squeeze the water out of your hair with your hands. Hair should be damp rather than dripping, because a mask applied to soaking hair is diluted before it touches anything.
2. Scoop out roughly a walnut-sized amount, about 5 mL, for hair above the collar. Use about double that, 10 mL, for anything longer. Take it out with clean hands or a spatula, since a jar picks up whatever you put into it.
3. Work it through the mid-lengths and the ends, where the damage actually is. Keep it off the scalp. Your scalp is where your treatments go, and this is not one of them.
4. Comb it through with a wide-tooth comb so the coating spreads evenly instead of sitting in clumps.
5. Leave it for five to ten minutes. Longer does not deposit more, and heat or a wrapped towel adds nothing here.
6. Rinse thoroughly until your hair no longer feels slippery, then dry as normal.

Two things worth getting right. Do not use the mask and the Repair Protein Conditioner in the same wash, because doubling the protein tends to leave hair stiff and squeaky. Skip the conditioner on mask day. And if you are using a topical minoxidil, dry your scalp completely before you apply it, and give the application at least four hours before any further washing.

The effect is cosmetic and it is immediate. Hair should comb more easily the same day, feel smoother along the lengths and hold together better under a brush. That result fades across the next few washes as the deposit comes off, which is what the weekly rhythm is for. Over two or three months of consistent use the honest benefit is length retention, meaning fewer broken ends and less of the fraying that makes thinning hair look worse than it is. It will not add hairs, change your hairline or slow hair loss. Any extra thickness you notice is the fibres you already have lying flatter and holding together, with the count on your head unchanged.

For external use only. This is a rinse-off product for the hair itself. Always wash it out, and keep it off the scalp. Avoid the eye area and rinse with water if it gets in. Stop using it if you develop irritation, itching or a rash on the scalp or neck.

If you have reacted to a hair product before, patch test a small amount on the inner forearm and leave it for 24 hours before using it fully. Hydrolysed keratin is animal derived, usually from wool, so this product is not suitable if you are avoiding animal ingredients. Keep the lid closed, store it out of direct heat, and keep it out of reach of children.