Viral Hack Checked: Ice-Cold Water Final Rinse for Shiny Hair?

Verdict: Partly. An ice-cold final rinse feels fresh and may calm frizz a little for the next hour, but it does not “seal the cuticle” in any lasting way, it won’t stop hair fall, and a conditioner or a drop of oil on the ends does far more for shine.

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The shower’s hot and relaxing. Then the video tells you to twist the tap to freezing for the last minute. You gasp, you shiver, your hair feels squeaky, and it looks a little shinier in the mirror. So does an ice-cold water rinse make hair shiny? A little, for a while, and not for the reasons the video gives, because the squeaky feel and the mirror shine have far more to do with the conditioner you used a minute earlier and the fact that you rinsed it out properly than with the temperature of the last splash. Mostly.

What the cuticle really is

Every hair has an outer layer of flat, overlapping scales called the cuticle, laid down like roof tiles pointing towards the tip. When the tiles lie flat, light bounces off smoothly and hair looks glossy; when they’re lifted or chipped, light scatters and hair looks dull and frizzy.

Here’s the part the hack leaves out. Hair above the scalp is dead. Truly. It has no muscles and can’t open or close anything on command, so while water does make the whole strand swell slightly and heat makes it swell a touch more, a few seconds of cold water don’t snap the scales shut like a door. Once the hair dries, the difference between a cold and a lukewarm final rinse is small.

Myth: cold water closes hair pores and stops hair fall

Hair doesn’t have pores to close. The follicle, the pocket each hair grows from, sits deep in the scalp skin and is fed by blood vessels that a minute of cold water barely reaches. Hair fall comes from the growth cycle, genes, hormones, low iron, thyroid, stress or recent illness. A cold rinse changes none of these. If you’re shedding heavily, our guide to the best hair oils compared won’t solve that either; a check-up will.

Did you know? Hot water isn’t the villain some videos make it. Very hot water can strip more natural oil from the scalp and leave hair feeling drier, but plain warm water is fine.

Where a cool rinse does help a little

Fair’s fair. Small wins exist.

• Less oil stripping: washing in warm rather than very hot water leaves more natural oil, which makes hair feel softer.
• Refreshing feel: a cool finish wakes you up and feels good in summer.
• Frizz for a while: some people find a cool rinse, straight after conditioner, keeps hair a bit smoother until it’s dry.

Lukewarm to cool works just as well as ice-cold for all of these. Nobody needs to freeze, stand gasping under the tap in January, or make their children do it before school because a video with a million views said the cold was the secret ingredient.

How to actually get shinier hair

Shine comes from smooth, undamaged strands with a thin film of oil or conditioner on the surface, which is why a head of hair that is gently washed, conditioned, pressed dry and finished with a drop of oil on the ends will outshine an ice-rinsed head every single time. Try this.

1. Wash in warm, not hot, water: comfortable on the inside of your wrist, like a baby’s bath.
2. Shampoo the scalp only: about a coin-sized amount, massaged into the roots; let the foam rinse down the lengths.
3. Condition the lengths: a coin-to-walnut-sized amount from mid-length to ends, left for 2 to 3 minutes.
4. Finish cool if you like: 20 to 30 seconds of cool water. Not needed, but pleasant.
5. Press dry: squeeze with a soft towel or cotton T-shirt. Don’t rub.
6. Seal the ends: 1 or 2 drops of oil or a pea-sized drop of serum on the ends once hair is almost dry.

If you’re unsure whether to reach for oil or serum at that last step, our explainer on the difference between hair oil and hair serum sorts it out. More viral routines are scored in our Viral Hacks Checked series.

Cold water rinse for hair: questions people ask