Hair breakage and split ends: causes, trimming, and when to see a doctor

Breakage and split ends come from friction, pulling, heat and repeated chemical treatments that wear away the outside of the hair. A split end cannot be mended; it has to be trimmed off. What you can do is stop new ones forming by handling your hair gently. Hair falling out from the scalp is a different matter: if it suddenly gets much heavier or comes out in patches, see a doctor.

Breakage and hair loss are not the same

	Breakage	Hair loss (shedding)
Where	The strand snaps along its length or at the end	The whole hair comes out of the scalp
What you see	Short uneven pieces, frizz, split ends	Full-length hairs
Main causes	Friction, heat, chemicals, pulling	The normal hair cycle, or something going on in the body
What to do	Change how you handle hair; trim split ends	If it is abnormal, a doctor needs to find the cause

According to the AAD, losing about 50-100 hairs a day is normal, because hair is always shedding and regrowing. Breakage is hair that was not due to fall out, but became so fragile it snapped.

Why ends split

The outermost layer of hair is a set of overlapping scales called the cuticle, which wraps the core of the strand. A review in the International Journal of Trichology explains that split ends form more readily from friction combined with twisting during combing and styling. Once the cuticle wears away, cracks run into the core of the strand. Hair that has had years of sun, wind and chemical treatments splits more easily.

Habits the AAD lists as damaging hair:

• Scrubbing shampoo through the whole length, and skipping conditioner
• Rubbing hair dry with a towel
• Brushing or combing wet hair roughly
• Using dryers, flat irons and curling irons often and too hot
• Tight styles such as ponytails, buns or tight braids
• Colouring, perming or relaxing too often
• Brushing 100 strokes a day, which is a myth

Split ends cannot be mended, only trimmed

No product can permanently join a split end back into one strand. Conditioners with proteins or silicones make ends look smoother and shinier and easier to style for a while, but the effect washes out at the next shampoo. The only way to really get rid of a split end is to cut it off.

Split ends cannot be repaired. Trimming them and preventing new ones is a better use of money than hunting for a repair product.

There is no research-backed number for how often to trim. Go by your own ends: when you see ends split in two, thin and frizzy tips, or more tangling than before, it is time to cut that part off.

Example: how far wet hair stretches before damage

The same review reports that hair that has never been chemically treated can stretch about 30% when wet without damage. Stretched 30-70%, it changes permanently; at 80%, it breaks.

Take a 10 cm length of hair caught in a tangle while wet:

1. A 30% stretch is 10 x 0.3 = 3 cm, so up to 13 cm long with no damage.
2. A 30-70% stretch takes it to 13-17 cm: permanent damage, even if you do not see it snap.
3. An 80% stretch, 18 cm: the hair breaks.

In a knot, the pulling force lands on just a few strands, which easily pushes them past the safe range. That is why conditioner matters, to cut friction, and why you work out tangles from the ends up with a wide-tooth comb instead of yanking from the roots. These figures are for hair that has never been chemically treated.

Gentle handling you can do every day

• Shampoo the scalp, and condition the lengths after every wash.
• Blot hair with a towel; do not rub.
• Comb with a wide-tooth comb from the ends up. Let straight hair dry a little first; comb curly hair while it is still damp.
• Use less heat: a low setting, once a week or less. More in this series’ article on heat styling.
• Tie hair loosely with covered elastics, and change styles so you do not pull the same spot every day.
• Space out colouring, perming and relaxing. If you need both a perm or relaxer and colour, the AAD advises doing the perm or relaxer first and colouring 2 weeks later.
• Wear a wide-brimmed hat for long periods in the sun.

Which hair loss needs a doctor

See a dermatologist when:

• shedding suddenly gets much heavier and hair comes out in clumps
• hair falls out in patches, leaving round areas of bare scalp
• the scalp is inflamed or scaly, or there are patches with small black dots of broken hair
• hair keeps thinning even after you change how you care for it

The AAD says heavy shedding often follows events such as losing a lot of weight, childbirth, a high fever or serious illness, surgery, ongoing severe stress or stopping birth control pills, and it usually starts a few months after the event. But patchy loss or thinning can come from other conditions that need a doctor’s diagnosis. Some of them stop hair from growing back if left alone, and wearing tight styles for a long time can also cause permanent hair loss. The earlier it is checked, the better the outlook.

If you think a medicine you take is causing hair loss, do not stop it yourself. Talk to the doctor who prescribed it first.

Common mistakes

What people do	What happens
Buy a split-end repair product instead of trimming	The split stays and travels up the strand
Drag a comb through wet tangles	Hair stretches past the safe range and breaks
Tie a tight ponytail in the same spot every day	Breakage at the tie, and risk of permanent loss
Colour and relax on the same day	Hair takes a heavy chemical load at once
Blame patchy hair loss on the wrong shampoo	Missing the chance to find the cause early

Sources

• 10 hair care habits that can damage your hair — American Academy of Dermatology
• Do you have hair loss or hair shedding? — American Academy of Dermatology
• Hair loss: Who gets and causes — American Academy of Dermatology
• Hair cosmetics: an overview — International Journal of Trichology (PMC)
• Can You Repair Split Ends? — McGill University Office for Science and Society