Frizzy hair: why it happens, and how to get rid of frizz without fighting your hair

Frizz is often treated as a defect to be eliminated, usually by something sold in a small bottle. It helps to see it for what it is: your hair responding to water, plus whatever has made it easier for that water to get in and harder for the strands to stay together.

That explains why so many products partly work, and why none of them work completely.

Why is my hair frizzy?

Humidity

Hair is held in shape partly by permanent chemical bonds, which take a perm or relaxer to change, and partly by weak hydrogen bonds, which water can break and reform. On a humid day, more water enters the fibre, those bonds rearrange, and the strand changes shape. Individual strands do this slightly differently, so they stop lying together and the outline of your hair blurs. Excess water can also swell the fibre and stress the cuticle.

This is ordinary chemistry rather than a flaw in your hair. It is also why a straight style drops out on a damp day: it was set using exactly those hydrogen bonds.

A rough or damaged cuticle

A smooth, intact cuticle slows water exchange and lets strands slide past each other. Bleach, heat, friction and age wear it away, particularly at the ends. Hair in that condition takes on and loses water more quickly, as the porosity guide explains, and it also catches on neighbouring strands. If your frizz is worst on the lengths and the crown is fine, damage is a strong candidate. If you also see blunt short pieces, read what hair breakage looks like, because short broken hairs make a halo that reads as frizz.

Dry hair

Frizz and dry hair often turn up together, though they are not the same thing. Dry hair feels rough and tangles, and often looks dull. A lack of water and lubrication leaves more friction between strands, so they separate. Routine moisture care often helps, if that is the problem. It will not help as much if your hair is over-soft and limp; the protein and moisture guide separates the two.

Curl pattern

Wavy, curly and coily hair has more bends, so it does not lie flat, and its strands are more easily separated from their clumps. Frizz in curls often shows that clumps have broken apart rather than that anything is wrong with the hair. The fix is about keeping curls together, which is a different job from smoothing.

Friction and handling

Rough towelling, brushing dry curls, cotton pillowcases, and touching your hair while it dries all rough up the surface or break up clumps. There is little formal research on towels and pillowcases, but the logic is simple and the changes cost little.

Hard water

Calcium and magnesium in hard water can deposit on the fibre and leave a rough film that blocks conditioner, which is why hair sometimes changes after a house move. The evidence on actual fibre damage is mixed. In one small study of 15 women's hair, soaking in hard water for a month made no significant difference to tensile strength or elasticity compared with distilled water. Another, using hair from 70 men and running for three months, found hard water reduced tensile strength. Neither measured frizz. If you see limescale at home and your shampoo barely lathers, the hard water guide is worth a look, as it is cheap to test with a chelating shampoo.

How to get rid of frizz

"Get rid of" is a little optimistic; "greatly reduce" is realistic. In rough order of impact:

Condition properly. Apply conditioner to soaking-wet hair, from the ends upwards, and leave it for a few minutes. This is where most routines go wrong, and it costs nothing to change.

Detangle wet, through conditioner. Use a wide-tooth comb, working from the ends up. Do not brush dry curls or waves unless you want a big, soft cloud. The detangling guide has the order of operations.

Add a leave-in on damp hair. A small amount reduces friction while hair dries. Leave-in vs deep conditioner helps if you are not sure which you need.

Seal with a film. A silicone serum or a very small amount of light oil on damp or dry ends lays down a surface film that adds slip and can slow water exchange. Silicones are a standard choice here, and they cannot suffocate hair, whatever you may have read. The silicones guide explains which ones build up. Be aware that much of the published support for anti-humidity films comes from manufacturers and patents, so judge a product by what it does on your own head.

Dry with less friction. Blot or squeeze with a soft cotton T-shirt or microfibre towel rather than rubbing. If you blow-dry, point the airflow down the strand and use a lower heat setting. Let hair dry fully before heading into humid air if you can.

Treat heat as expensive. Heat can smooth hair for the day, but repeated high heat wears down the cuticle and leads to more frizz in the long run. Lower temperatures and heat protection are worth the small effort.

Check that it is not buildup. Hair that feels coated and stops responding to products may need one clarifying wash, not another layer.

Frizzy curly and wavy hair

The priority here is keeping clumps together rather than flattening anything.

• Apply styler to soaking-wet hair so strands can clump before they dry.
• Use a gel if you want hold. It dries to a firm cast that protects the shape while it dries.
• Do not touch it until it is completely dry, then scrunch gently to break the cast.
• Accept a little frizz. Some is normal in a curl pattern, and chasing zero usually means too much product.

The full routine is in how to wash curly hair, and a curly wash day that works cuts it down to the essentials.

What will not fix frizz

• More and more product. Past a certain point, it just weighs hair down and builds up.
• Shower-head filters sold as softeners. As the hard water guide explains, they do little to remove calcium and magnesium.
• Permanent fixes in a bottle. Anything that washes out has only a temporary effect. Chemical smoothing can last longer, but carries its own trade-offs.

Where to start

Pick the likeliest cause and change that first: weather you can only manage, but water, friction, heat and conditioning are all in your hands. Give it several washes and compare. If you want help working out your starting point, the two-minute hair test turns six questions into a simple routine.