A few crinkly or wiry strands scattered among otherwise smooth hair is extremely common, and it usually comes down to one of a handful of causes: heat damage, hormonal shifts, aging, or mechanical stress. Sometimes it’s a single factor, sometimes several working together. The good news is that most causes are identifiable and many are preventable.
Heat Damage and Bubble Hair
The most common culprit behind random crinkly strands is heat styling. When wet or damp hair is exposed to high temperatures from a blow dryer, flat iron, or curling iron, gas bubbles can form inside the hair shaft itself. This is called bubble hair, and it leaves strands feeling rough, brittle, and visibly kinked or crinkled in spots. The bubbles are essentially tiny pockets where moisture inside the strand flash-evaporated, permanently distorting the hair’s internal structure.
The threshold matters: hot tools used on damp hair or at temperatures above 175°C (about 347°F) are the primary triggers. Using a flat iron or hot comb more than once a week also increases the risk. If you notice crinkly patches midway down certain strands rather than at the root, heat damage is a strong possibility, since the damage happens wherever the tool made contact. This kind of texture change is permanent on the affected section of hair, but new growth from the follicle will be normal.
Hormonal Changes and Hair Texture
Hormones directly control the size of your hair follicles and the type of hair they produce. During puberty, pregnancy, menopause, or periods of significant hormonal fluctuation, your follicles can shift from producing one texture to another. Androgens (the group of hormones that includes testosterone) are especially influential. They can cause follicles to grow larger and produce thicker, coarser hairs in some areas while simultaneously shrinking follicles elsewhere.
There’s a specific condition called acquired progressive kinking of hair (APKH) that shows up in young adults, particularly around the temples and sides of the scalp. Hair in those areas turns coarse, curly, and dull while the rest of the scalp stays normal. In some cases the affected strands even change color. APKH has been linked to higher concentrations of a potent androgen in the scalp and to the early stages of pattern hair loss. If you’re noticing crinkly strands concentrated at your temples or the sides of your head, this hormonal connection is worth paying attention to.
Thyroid imbalances can also alter hair texture, making strands feel dry, coarse, or wiry. If the crinkly texture appeared alongside other symptoms like fatigue, weight changes, or skin dryness, a thyroid issue could be the underlying driver.
Aging and Gray Hair
If the crinkly strands you’re finding happen to be gray or white, that’s not a coincidence. Gray hair is structurally different from pigmented hair. It contains significantly less of the internal lipids (natural fats) that give hair its flexibility, smoothness, and moisture retention. Specifically, gray strands have lower levels of ceramides and fatty acids, and the lipid layers that remain are more disordered. This makes gray hair more permeable to water but paradoxically drier overall, since moisture passes through it more quickly instead of being held in place.
The result is hair that feels wiry, rough, or crinkled compared to the pigmented strands growing right next to it. Age also plays a role beyond graying. Women in their 50s produce measurably less scalp sebum (the natural oil that coats and softens hair) than women in their 20s, and their scalp skin becomes firmer. Less oil means less natural conditioning at the root, which can make emerging strands feel coarser from the start. In men, these sebum changes are less pronounced with age, which partly explains why texture shifts tend to be more noticeable for women.
Mechanical Stress and Knotting
Sometimes a strand looks crinkly because it’s been physically deformed. Vigorous towel drying, rough brushing, friction against pillowcases, and even scratching your scalp can create tiny kinks, bends, and knots in individual strands. This is especially true for hair that’s naturally on the finer side or has a flat, ribbon-like cross section rather than a perfectly round one.
Ribbon-shaped strands naturally spiral and recoil when disturbed. Repeated friction can tangle them into small, tight knots, a condition called trichonodosis, where the strand literally ties itself. Once a kink or knot forms, continued handling only tightens it, making the strand feel permanently crinkled even though the follicle is producing normal hair. You’ll typically notice this near the ends of longer hair, where strands have had months or years of exposure to mechanical forces.
Chemical Treatments and “Scab Hair”
If you’ve recently stopped relaxing, perming, or otherwise chemically treating your hair, the first few inches of new growth can feel unusually rough, dry, and texturally inconsistent. This is sometimes called “scab hair.” The theory is that residual mineral deposits from previous chemical treatments coat the new growth as it emerges from the follicle, preventing the strand from absorbing moisture properly and masking its natural curl pattern.
This phase is temporary. As the hair continues to grow and the chemically influenced section is trimmed away, your natural texture returns. The transition period can last several months to over a year depending on how fast your hair grows, which averages roughly half an inch per month.
How to Tell What’s Causing Yours
Location on the strand is one of the best clues. Crinkly texture that appears midway down the hair shaft, away from the root, points toward heat damage or mechanical stress. Crinkly texture that starts right at the scalp and extends the full length of the strand suggests a follicle-level change, whether from hormones, aging, or a condition like APKH.
Color is another useful indicator. If the crinkly strands are gray or white while your smooth strands are pigmented, the lipid differences in unpigmented hair are the likely explanation. If the crinkly strands are also darker or duller than surrounding hair, hormonal shifts become more plausible.
Pattern matters too. A few scattered strands across your whole head is usually benign, often just the natural variation in follicle shape that everyone has. A cluster of wiry strands concentrated at the temples or hairline, especially if that area also seems to be thinning, is worth monitoring for early pattern hair loss. And if the texture change appeared suddenly or affects a large percentage of your hair, looking into hormonal or thyroid causes is a reasonable next step.