Hair Breakage: What Causes It and How to Stop It

What causes hair breakage?

Breakage needs two things at once: a fiber that is already weakened, and a comb or brush meeting a tangle that bends it further than it can take.

A straight pull rarely does it. A healthy hair takes two to three times more force to snap by stretching than to come out of the scalp, and it must first stretch by 40 to 50% of its length. Hair on a head is almost never pulled that hard or stretched that far. In experiments filmed inside a scanning electron microscope in the 1970s, combing looked like this: hairs in a tangle looped around one another, the comb dragged through, and one strand bent sharply over its neighbor and fractured at the bend (Swift 1999). Reviewing the combing studies, the hair chemist Clarence Robbins found that breakage rises with combing force, so anything that adds tangles or friction adds broken hairs (Robbins 2012).

How much force a fiber can take depends on what it has been through.

In one lab test, bleached hair broke nearly four times as many long pieces as unbleached hair under the same combing, 102 against 27 (Robbins and Kamath 2007). Damage also builds before it shows. In a small study, women who regularly bleached, dyed or straightened their hair had significantly more shaft damage under the electron microscope than women who did not, though both groups looked alike to the eye (Kaliyadan 2016). For lightening in detail, see how to repair bleach-damaged hair.

Is it hair breakage or shedding?

Look at the end of the hair. A hair that came out at the root carries a small, pale bulb. A broken hair has none and ends in a blunt, jagged or frayed tip, often well short of your full length. Researchers who count hairs collected from combs sort them exactly this way (Robbins 2012).

This article covers breakage of the fiber. Hair coming out at the root in larger amounts than usual, or any change in the scalp, is a different question, and a dermatologist is the right person to ask (AAD).

What is fried hair, and why does it feel like straw?

"Fried" and "straw" are not technical terms. People use them for hair that feels dry, rough and stiff, looks dull, tangles within minutes and snaps, usually after bleach, heat or both. Most of those sensations have a measured cause.

The roughness starts at the surface. A single lab bleach stripped about 80% of the water-repellent surface lipid (Habe 2011), and friction climbs with every bleach: in Robbins's measurements, three mild bleaches raised fiber friction by about 70%, from a coefficient of 0.249 to 0.427. Rough hair catches on itself, which is how tangles start.

Shine needs a smooth surface that reflects light in one direction. Oxidizing the surface made hair look less shiny to independent observers, and abrasion dulls it further by breaking scale edges (Robbins 2012).

Heat adds to the dry, stiff feel. In lab tests, flat-ironed hair took up less water and held on to it less well than untreated hair (Zhou 2011). Brief, focal heat on damp hair forms bubbles inside the fiber, leaving "weak, dry and brittle hair which breaks easily" (Gummer 1994).

Fried hair looks duller than the regrowth, with frizzy, split or uneven ends, short broken pieces standing up along the part, and sometimes tiny white dots along the strand. Each dot is a point where the fiber has frayed lengthwise into fine strands that scatter light, and the hair tends to break there (Swift 1999).

How do you fix straw hair?

Treat the surface first: condition after every wash, add a leave-in to the lengths, lower the heat and never iron damp hair. Then trim the ends that still snag or split; steps 2, 6 and 9 of the stop-and-fix list below give the detail. Lightened hair that feels fried is also more porous. Heat damage is more mixed, since hot irons can open voids yet lower how much water the fiber holds. For what porosity changes in your routine, see high porosity hair.

Self-check: what is causing your hair breakage?

You need a freshly used brush, white paper (or a dark towel for light hair) and daylight. The check reads the history in your hair; it does not diagnose anything.

1. Sort. Lay out the hairs from your brush and the sink. Set aside any with a bulb; everything else broke.
2. Measure the broken pieces. Mostly short bits, under an inch, mean the damage sits at your ends, where worn tips wrap around teeth or bristles. Mostly longer pieces mean snags higher up, which are more common with a brush than a comb (Robbins and Kamath 2007; Robbins 2012).
3. Look along a few strands against the paper. A tip that has forked in two is a split end. White dots along the shaft are weak points where the hair is likely to break.
4. Note where it happens. Short hairs in a band where you tie your hair point to tension. Short, frizzy pieces in the sections you straighten or curl most point to heat. Breakage through lightened lengths but not in the regrowth points to bleach or color; see is bleached hair high porosity?
5. Compare roots with ends. Slide two fingers along a clean, dry strand near the scalp, then near the ends, moving toward the tips both times. The root section is the least damaged part of the same hair, so a clear change in roughness is a record of damage. If lightened lengths stretch far and stay stretched when wet, read about gummy hair.

What the brush cannot tell you is how your color, heat and washing add up. The free hair consultation asks about exactly that, and about how your hair behaves, then scores porosity and damage from your answers. It takes about a minute and asks for your email before it shows your Damage Profile, with a routine matched to it. Take the free hair consultation

Can damaged hair be repaired?

No broken hair can be rejoined. A fracture or split cannot be fused back into one intact fiber, so there is no cure for hair breakage that has already happened. The hair you see is not living tissue and cannot repair itself; the damage stays until it is cut off, and new growth arrives undamaged. What you can change, often sharply, is how much more of it breaks.

In practice, repairing damaged hair means lowering friction and adding no new damage. Conditioners have the strongest evidence, because lower friction means fewer breaks. In the Robbins and Kamath test, conditioned bleached hair broke 18.7 long pieces on average against 102 without conditioner. In a recent study on bleached hair, a shampoo and conditioner with silicones and oils cut the fragments released early in combing from 18 to 43 down to 1 to 3 (Davies 2026). The authors work for or consult to the testing-equipment and cosmetics industries. Conditioners partly wash off, so they help only while you keep using them.

Heat-protective polymers reduced breakage after flat ironing in a supplier's lab study (Zhou 2011). For treatments aimed at the inside of the fiber, including bond builders, independent evidence is thin and mixed: one university study found a maleate-based treatment left on bleached hair raised the breaking strength of single fibers tested dry (Martins 2024), while another found no increase in disulfide bonds in the cortex after maleate-type treatments (Di Foggia 2021). Read what hair bonds are and what bond repair means before trusting any claim, ours included, and how hair strength is measured for why a straight pull tells only part of the story.

How do you stop and fix hair breakage?

Fixing breakage means lowering the force each strand meets and adding no new damage. In order:

1. Name the cause. List the past year: lightening, color, relaxers or perms, heat tools, sun and pool.
2. Condition after every shampoo, on the lengths and ends where the damage is. On lightened or heat-styled hair, add a leave-in so the lengths keep a lubricating layer between washes (AAD; Robbins 2012).
3. Wash the scalp and let the lather rinse through the lengths. Press water out with a towel instead of rubbing; rubbing wet hair wore the cuticle away in a 1976 microscope study (AAD; Robinson 1976).
4. Detangle from the ends up, slowly, with a wide-tooth comb. Let straight hair dry a little first; detangle curly or coily hair damp, with conditioner in. The next section explains why. Skip backcombing, which can fracture the shaft (Williams 2025).
5. Space chemical services. The AAD advises one service at a time, more time between touch-ups (especially when the air is dry), and perming or relaxing 2 weeks before coloring. Hair that has already been lightened is hit harder by the next chemical service.
6. Lower the heat. Never iron damp hair. Use the lowest setting that works, fewer passes and a heat protectant; no temperature is entirely safe.
7. Release the tension. Tie hair loosely with covered elastics, and change styles so the same section is not held tight every day (AAD).
8. Shield it from sun and pool. Wear a hat in strong sun and a swim cap in the pool, rinse right after swimming, then condition (AAD).
9. Trim what has already split or frayed. A frayed section bends more easily, so the next tangle concentrates its force there (Swift 1999).

Why does hair break when you brush it?

One stroke combines bending, friction and impact, and finds every weak point at once. The brush is usually the moment hair breaks, rarely the original cause.

Short pieces break at the end of the stroke. As the brush reaches the tips, worn ends wrap around the bristles and the force spikes, and with repeated dry combing, short-piece breakage rises as the ends wear (Robbins and Kamath 2007).

Whether to comb wet or dry depends on your curl. Straight and wavy hair takes more force to comb wet and breaks into more long pieces, because water softens the fiber and lowers its breaking load. Tightly curled hair breaks more when combed dry (Robbins 2012). Lightened hair is weakest wet: after bleaching, wet strength falls almost in step with lost disulfide bonds while dry strength barely changes, which is why bleached hair can brush out fine dry and snap in the shower (Robbins 2012).

Combs and brushes with wider-spaced teeth or bristles form fewer, simpler tangles and break fewer hairs (Robbins 2012). Earlier damage decides how much any of this matters. In a 1976 study, virgin hair shorter than about 15 cm (6 inches) almost never split under ordinary grooming, while permed or bleached hair of that length often did (Robinson 1976). So "my hair snaps when I brush it" has two answers: handle the hair so it meets less force, and find out why ordinary grooming has become too much for it.

Which treatment is best for hair breakage?

The one that matches the cause, used with the handling changes above. Conditioner after every wash has the best evidence for any breakage. If heat is the cause, add a protectant and turn the temperature down. Lightened lengths carry damage through the fiber, so one product on its own will not be enough.

For lightened hair, ANATOMY makes the Complete Reconstruction System: a shampoo, a conditioner and the 100 ml Leave-In. It is made in Switzerland and patented, built on click chemistry, the reaction class recognized by the 2022 Nobel Prize in Chemistry, and independently tested at SGS proderm in Germany, on bleached hair.

Where should you start?

Start with the hairs in your brush, which show where your hair breaks. Because breakage happens at the bend, every step above either lowers the force each strand meets or stops new damage from weakening the fiber further. To match those steps to what your hair has been through, take the free hair consultation; it takes about a minute and asks for your email before showing your Damage Profile.

Frequently asked questions

Can broken hair grow back?

The broken piece does not reattach. The hair still attached at your scalp keeps growing as before, because breakage happens in the shaft, away from the root. What grows in is undamaged; how long it stays that way depends on the heat, chemistry and handling it meets.

What is the biggest cause of hair breakage?

Tangles during combing and brushing, acting on hair that chemistry, heat or sun has already weakened. Breakage rises with combing force, and bleaching, perms and relaxers all raise friction, which raises that force (Robbins 2012).

How long does it take for fried hair to recover?

The damage leaves only as hair grows and is trimmed, though conditioning changes how it feels from the next wash. Scalp hair grows on average about 1 to 1.3 cm (roughly half an inch) a month, around 15 cm (6 inches) a year, and more slowly for some people (Robbins 2012). Expect months for short hair, years for long.

Do silk pillowcases stop hair breakage?

We found no published study that tests it. Friction does drive breakage, so a smoother surface is plausible, but until someone measures it, treat it as unproven and put conditioning and gentler detangling first.

What is my body lacking if my hair is breaking?

That is a medical question for a dermatologist or physician, not a haircare brand. The research on breakage of the hair shaft documents chemical processing, heat, sun and grooming as causes. If hair is also coming out at the root, or breakage started with no change in your routine, see a dermatologist.

How do you fix hair breakage naturally?

Most of what reduces breakage costs nothing: detangle slowly from the ends up, brush only to style (the AAD calls 100 strokes a day a myth), tie hair loosely, press water out instead of rubbing, and turn the heat down. Among products, conditioner after every wash has the best evidence. Breakage that has already happened can only be trimmed.

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