What's your hair type, and why it matters

What decides the shape of your hair

It all starts in the hair follicle, the small pocket in the scalp that each strand grows out of. The rule fits in one sentence. A straight follicle gives a straight hair, a curved follicle gives a curly hair. The sharper the curve, the tighter the curl.

The key study on the subject, carried out on human follicles that were harvested and examined under the microscope, showed this without ambiguity: the shape of the follicle programmes the shape of the hair, right from the bulb. The bulb of a coily hair is not symmetrical. It grows at a slant. And keratin, the protein that stiffens the hair, does not lay down evenly all the way around the shaft. One side hardens before the other. The result? The shaft curls as it emerges, exactly like a strip of metal heated on one side only.

The cross section, your hair signature

Cut a hair, look at its section under the microscope. You can read its type there like an open book. Straight hair has an almost round section. Wavy and curly hair draws a flattened oval. Coily hair shows the most elliptical section of all, almost a ribbon.

This geometry is not just a cosmetic quirk. A round shaft resists evenly in every direction. A flat shaft does not: it has weak points, and it breaks where it is thinnest. That is why very curly hair often passes for fragile. And it is also why, during a transplant, a curved graft calls for a steadier hand than a straight one, as we will come back to.

Eight types, not three

We tend to sort hair into four broad families: straight, wavy, curly, coily. Science goes further. A large study run on 2449 people across 22 countries proposed a classification into eight degrees of curl, from perfectly straight to very coily. The advantage of this scale? It describes your hair for what it is, using measurable criteria such as the diameter of the curl or the number of waves, without tying it to an ethnic origin, which weighed down the older models.

Here is how to read this scale, in steps of two degrees:

• Types I and II, the straight ones. Type I falls perfectly straight, without the slightest wave. Type II stays straight but starts to show a very slight movement over a long length. The shaft is almost round in section.
• Types III and IV, the wavy ones. A gentle wave appears, more and more pronounced. Type IV already forms clear S shapes along the whole length. The section flattens into an oval.
• Types V and VI, the curly ones. Real curls appear, in a loose spiral at V, tighter at VI. Sebum starts to struggle to travel down the shaft.
• Types VII and VIII, the coily ones. Very tight curls, corkscrew or zigzag shaped. Type VIII is the coiliest of all, with a ribbon-like section and repeated twists. It is the most demanding to style, and to transplant.

The higher the number, the stronger the curve of the follicle under the skin, the flatter the shaft in section, and the more the hair calls for moisture and care. This scale is not a theoretical detail: it guides the choice of instruments and angles on the day of a transplant.

And your genetics weigh heavily here. Several genes drive hair shape, among them trichohyalin (the TCHH gene) and the EDAR gene. The hereditary share of curl is high. Put simply: if your parents have curly hair, the odds are you will too.

Straight, wavy, curly, coily: what to expect

Each type has its own care logic. Understanding yours saves you a fair few mistakes.

Straight hair lets sebum slide along without effort, from root to tip. It gets greasy quickly at the crown but stays well nourished along its length. Its weak spot: it gives away a lack of volume, and thinning shows up sooner than elsewhere.

Wavy and curly hair lives a compromise. Sebum struggles to travel down the spirals. The lengths tend towards dryness. Nothing dramatic, but it calls for regular moisture and a light hand when detangling.

Coily hair is the most demanding by a long way. Its ribbon structure and repeated twists block sebum well before the tips. The shaft has twist points where it thins, and that is precisely where it snaps under the comb. Not a flaw: a mechanical feature, to be respected.

Your care, type by type

The right routine is not the most expensive one, it is the one that fits your texture. Here are the markers that work, from straightest to coiliest:

• Straight hair. Wash every 2 to 3 days, light products that do not weigh the fibre down, never a heavy mask at the roots. Keep serum for the tips. Combing is easy, on dry or damp hair, with no particular difficulty.
• Wavy hair. Wash about twice a week, a hydrating conditioner at every wash, scrunch the lengths as they dry to wake up the wave. Avoid brushing dry, which breaks the movement and creates frizz.
• Curly hair. Wash 1 to 2 times a week, rich products, detangle only on wet hair loaded with conditioner, using a wide-tooth comb or your fingers. Dry gently, ideally in the open air or with a diffuser on low heat.
• Coily hair. Space washes out, once a week or less, near-daily moisture (milks, butters, oils), detangle only on damp hair coated with product, section by section, from the tips towards the roots. Ban the fine comb and aggressive heat.

One rule holds for everyone: the stronger the curl, the more gently you wash, the more you moisturise, and the more you handle the hair when it is wet. A good diet and a steady sleep pattern support the health of the hair follicle, whatever the type.

Density and growth speed vary too

Hair type often comes with differences in density and growth. Researchers measured that African-type hair grows more slowly, around 256 micrometres per day, against 396 for Caucasian-type hair. Density is lower too, around 190 hairs per square centimetre against 227.

These figures matter, and not only day to day. Slower growth means that after a haircut or a transplant, visible regrowth takes a little longer to show. A question of patience, not of effectiveness. A lower starting density also feeds into the calculation of the donor area during a transplant: it is one of the parameters the surgeon assesses before settling on a plan. To grasp the natural rhythm of your hair, the hair cycle sets out each phase, from growth to shedding.

Hair type and hair loss: what really changes

The bad news first: your hair type does not shield you from baldness. Androgenetic alopecia, linked to the hormone DHT, hits every texture. DHT acts like a weedkiller on sensitive follicles, whether straight or coily. No curl protects you from this hormonal mechanism.

That said, certain types are exposed to very specific kinds of loss. Coily hair, often pulled tight into braids, weaves or locs, takes repeated tension at the root. Ideal ground for traction alopecia, a mechanical loss that hits the temples and the front hairline first. Hair loss after African braids is the most common example of it. The good news: caught in time, before the follicle closes for good, it reverses. Caught too late, it leaves scarred zones where nothing grows any more, and only a transplant can then rebuild a hairline.

Another point, which mostly affects the other end of the spectrum. On fine, straight hair, the scalp becomes visible through the hair far sooner than under a curly, voluminous head. Curls camouflage. Straight hair reveals. The same amount of lost density therefore shows up much earlier on a straight texture: that is often what pushes patients with straight hair to seek advice before the others. If your hair is thinning, you will spot it sooner on a straight texture.

Whatever your type, catching the signs of baldness early changes everything. The faster you act, the more the options stay open, whether that means medical treatment or, later, a transplant.

Why your hair type matters for a transplant

This is where geometry takes back all of its rights. In an FUE hair transplant, the surgeon harvests follicles one by one, with a small cylindrical punch barely a millimetre across. On straight hair, the follicle runs straight under the skin, and the punch follows the shaft without trouble. The extraction is clean, the graft comes out intact.

On coily hair, everything gets complicated. The shaft dives straight at the surface, then the follicle curves under the skin, where the eye cannot see it. The punch goes straight ahead. The danger? That the instrument cuts the curved follicle along the way and severs the graft before it has even come out. This phenomenon has a name, the transection rate, and it measures the share of grafts damaged during extraction. With a standard punch on very curly hair, this rate climbs fast, and every lost graft is one hair less in the final result. With a non-rotary curved punch built for curl, it drops below 5%.

The mechanics of extraction, step by step

To understand why coily hair complicates a transplant, follow the instrument under the skin:

• The extraction angle. On straight hair, the angle of the visible shaft matches the angle of the follicle. On coily hair, it does not: the root sets off in a different direction from what you see at the surface. The surgeon has to read the real curve and tilt the punch accordingly.
• Depth and curve. The tighter the underground curl, the more the punch risks crossing the shaft. Hence the value of a blunt punch that pushes the tissues apart instead of cutting them, and lets the follicle slide along its axis.
• Implantation. At the placement stage, the angle and orientation of each graft decide the look. A coily hair set the wrong way curls in the wrong direction and shows. Placed well, it blends into the existing hair.

A natural result depends directly on this command of texture. A curly graft survives just as well as a straight one, provided it is extracted without breakage and implanted at the right angle. That is the whole challenge for a team used to curly textures.

A method that adapts, not a standard one

The answer is not to give up. It is to adapt. A non-rotary curved punch that follows the curl of the follicle, or a blunt punch that pushes the tissues apart, and an extraction angle set on the real curve rather than the shaft you see at the surface. This expertise makes all the difference on coily hair.

It is exactly the speciality of afro hair transplant work at Dr Cinik’s. As for Asian hair, thicker and straighter, it calls for its own specific approach too: its larger diameter changes the punch calibre and the spacing of the implants. Each texture has its rules.

One point in favour of curly hair: at equal density, it gives an impression of better coverage. A curl takes up more space than a straight hair and hides the scalp beneath it more effectively. The number of grafts needed can therefore be optimised for the same effect of visual density. Once regrowth settles in, the curl works in your favour.

Identify your type well, treat it well

To recognise your type, look at a clean, dry hair, with no product on it at all. Does it fall straight? Does it draw a wave, a curl, a tight spiral? The water test gives you a hand: when wet, the hair reveals its natural curl, often more pronounced than when dry.

Once you have pinned down the type, you set the routine described above and stay consistent. It is consistency that pays off, not piling up products. And if hair loss sets in, no panic. Hair loss treatments that genuinely work exist for every texture, and a transplant takes over when the follicle is already lost.

What to do when your hair type complicates things

Your texture guides the choice of method. Here is how that plays out in practice at Dr Cinik’s, depending on your case.

Coily hair and advancing baldness. A transplant is still an excellent option, on one condition: that it is done well. Everything hinges on expertise in follicular curve. Afro hair transplant work uses curved or blunt punches and calibrated angles to reduce the transection of coily grafts. In practice, this means slower, more meticulous harvesting, and a team specifically trained on curl. For the transplant plan, we account for donor density, often lower, and for the natural volume effect of curls, which can ease the number of grafts to place.

Fine, straight textures that are thinning. The DHI method implants the graft directly with an implanter pen (the Choi), with no prior incision. The result: very dense implantation and fine control of the growth angle, valuable for rebuilding a natural hairline on a head where the scalp already shows. It is often the option of choice for straight hair, which forgives little.

Healing and comfort. Sapphire FUE opens the recipient channels with ultra-fine sapphire blades, more precise than steel. Cleaner micro-incisions mean faster healing and implants placed closer together, so a higher visual density, whatever the texture.

As a complement. PRP, included in every package, reinjects your own growth factors to stimulate the follicles already in place and support regrowth. It does not replace a transplant, it complements it, particularly on fine textures where every existing follicle counts.

With more than 20 years of experience and more than 50000 patients, Dr Cinik calibrates each procedure to the texture, the density and the donor area of each person. The protocols follow the international ISHRS standards. Feel free to ask for a free consultation: with no commitment, it helps you see clearly what truly suits your hair type. You can also browse the before and after results to picture what is possible.

Scientific references

Cloete, E., Khumalo, N. P., & Ngoepe, M. N. (2019). The what, why and how of curly hair: A review. Proceedings of the Royal Society A, 475(2231), 20190516. https://pmc.ncbi.nlm.nih.gov/articles/PMC6894537/

Lasisi, T., Smallcombe, J. W., Kenney, W. L., Shriver, M. D., Zydney, B., Jablonski, N. G., & Havenith, G. (2025). Quantifying whole human hair scalp fibres of varying curl: A micro-computed tomographic study. Journal of the Royal Society Interface. https://pmc.ncbi.nlm.nih.gov/articles/PMC11733847/

Loussouarn, G. (2001). African hair growth parameters. British Journal of Dermatology, 145(2), 294-297. https://pubmed.ncbi.nlm.nih.gov/11531795/

Loussouarn, G., Garcel, A. L., Lozano, I., Collaudin, C., Porter, C., Panhard, S., Saint-Léger, D., & de La Mettrie, R. (2007). Worldwide diversity of hair curliness: A new method of assessment. International Journal of Dermatology, 46(Suppl. 1), 2-6. https://pubmed.ncbi.nlm.nih.gov/17919196/

Onwudiwe, O., Ali, R., Sinclair, R., & Lim, H. W. (2016). Comparative study of a novel tool for follicular unit extraction for individuals with Afro-textured hair. JAAD Case Reports, 2(5), 367-370. https://pmc.ncbi.nlm.nih.gov/articles/PMC5055031/

Thibaut, S., Gaillard, O., Bouhanna, P., Cannell, D. W., & Bernard, B. A. (2005). Human hair shape is programmed from the bulb. British Journal of Dermatology, 152(4), 632-638. https://pubmed.ncbi.nlm.nih.gov/15840107/

Westgate, G. E., Ginger, R. S., & Green, M. R. (2017). The biology and genetics of curly hair. Experimental Dermatology, 26(6), 483-490. https://pubmed.ncbi.nlm.nih.gov/28370528/