How to know your hair type: the ultimate guide for curly hair

Knowing your hair type goes beyond identifying your curl pattern—whether you're a 3A, 4C, or somewhere in between. Your hair type includes texture (individual strand thickness), density (total strand count), and porosity (how moisture moves in and out of your hair). These factors determine which products will enhance your hair and which will leave it looking disappointing.

For curly and coily textures, there's a structural challenge. The spiral shape prevents natural scalp oils from traveling down strands evenly. Oil sits at the roots while ends stay undersupplied. Most hair care advice assumes even oil distribution, so it tends to miss for textured hair.

In this guide: curl patterns, texture, density, porosity—and how to use that information to build a routine that works for your hair.

The hair type classification system

The standard system categorizes hair into four types based on curl pattern:

Type 1: Straight hair with no curl 

Type 2: Wavy hair with S-shaped bends 

Type 3: Curly hair with defined spirals 

Type 4: Coily hair with tight zigzag patterns

Each type breaks down further into A, B, and C. These subcategories account for curl tightness and strand thickness. Someone with "3B hair" has curly (type 3) hair with medium tightness and thickness (B).

Most people don't have uniform hair. You might have 3A curls on top with 3B underneath. Or 4B at the crown and 4A around your hairline. That's normal. Use these categories as reference points for understanding what your hair needs.

Understanding curl patterns in detail

Type 2: wavy hair

Type 2A hair
Type 2A tends to be pretty flat at the roots with gentle waves starting around mid-length. These waves are easily straightened and sometimes struggle to hold definition without product. If you have thick 2A hair, you'll notice more body and volume happening, while fine 2A hair tends to fall flat.

Type 2B hair

Type 2B has more defined S-shaped waves that start closer to the roots. There's more volume here, and you'll notice some frizz making an appearance in humid weather.

Type 2C hair
Type 2C is where things get interesting—these waves are thick, coarse, and verging on actual curls. They hold their shape when air-dried and have serious volume potential. This hair type responds well to curl-enhancing products.

Type 3: curly hair

Type 3 forms distinct loops and spirals. The curl structure prevents natural scalp oils from traveling down the shaft easily, making moisture retention critical.

Type 3A hair
3A hair features loose, springy curls roughly the width of a piece of sidewalk chalk. These well-defined spirals have natural shine when properly hydrated, though humidity can turn them into a frizz situation fast.

Our CURL-DEFINING Shampoo Bar works particularly well here. Sulfate-free, packed with cocoa and shea butter—it gently cleanses while keeping moisture levels where they need to be. Clinical studies show it increases shine by 70% when you pair it with the conditioner bar.

Type 3B hair
3B brings tighter ringlets, about the circumference of a Sharpie marker. These curls have volume and spring, but they need consistent hydration. Finger-coiling techniques help enhance their natural pattern.

The CURL-DEFINING Conditioner Bar is silicone-free—no buildup weighing down those coils. Improves manageability by 6x after one use. Shea butter, cocoa butter, glycerine—everything 3B curls need in one concentrated bar.

Type 3C hair
Tight, densely packed corkscrews about pencil-width. You get maximum volume here, along with significant shrinkage—your hair can look 50-70% shorter when dry than its actual length. These curls need intensive moisture and gentle handling. Protective styling helps, as does minimal manipulation. Less touching means less breakage.

Type 4: coily hair

Type 4 is the most delicate of all curl categories. Research in the International Journal of Cosmetic Science shows coily hair retains less moisture than other textures—the tight coil pattern creates more surface area for moisture to escape. Shrinkage can reach 75% of actual length. That's healthy elasticity at work, not a problem.

Type 4A hair
Visible S-shaped coils about the size of a crochet needle. These coils feel springy and soft when properly moisturized. Emollient-rich products work best here—particularly those with shea butter and coconut oil. They help retain moisture and definition.

Type 4B hair
Sharp Z-pattern bends rather than smooth curls. Fragile texture. These coils need protective styling, rich creams, and minimal manipulation. Without product or styling techniques, curl definition won't show much.

Type 4C hair
The tightest coil pattern—densely packed zigzags that might be nearly invisible without manipulation. Needs intensive moisture routines. Deep condition frequently. Detangle carefully using only fingers or wide-tooth combs. These coils are delicate, even when they don't look it.

Hair texture: diameter matters

Hair texture refers to strand diameter, separate from curl pattern. You can have curly hair with fine strands. Or straight hair where each strand is thick and coarse.

Take a single strand and rub it between your fingers. Can barely feel it? That's fine hair—delicate and easily weighed down. Some fine, high-porosity hair needs richer formulas to hold moisture, though. Texture and porosity work together.

A slight presence when rubbing a strand means medium texture. Neither delicate nor coarse.

The strand feels thick and substantial, like thread? Coarse hair. This texture can handle heavy products and is generally more resilient to heat, styling, and weather.

Two people with 3B curls can need totally different products based on strand thickness alone. The curl pattern looks similar from a distance; the care requirements don't match at all.

Hair density: strand count per square inch

Hair density is how many strands you have per square inch—not to be confused with strand thickness. They're different things. Low-density hair needs volumizing products that won't weigh it down. High-density hair can handle richer, heavier formulations without appearing flat.

To figure out your density, pull your hair into a ponytail and measure the circumference. Less than 2 inches around? That's low density. Between 2-3 inches is medium. 4+ inches means you have high density.

For comprehensive testing methods and product recommendations, see our in-depth guide to hair density.

Hair porosity: absorption and retention capacity

Porosity is how well your hair strands absorb and retain moisture. Research in the Journal of Cosmetic Dermatology shows it depends on cuticle condition—that outermost protective layer. A smooth, closed cuticle creates low porosity. Raised or damaged cuticles? High porosity.

Drop a clean strand in water. What happens? Floats on top means low porosity—tight cuticle. Sinks slowly means medium porosity, nicely balanced. Sinks immediately? High porosity from an open or damaged cuticle.

For curly hair, this matters more than most people realize. Low porosity requires lightweight products that can penetrate—glycerine and hyaluronic acid. High porosity needs heavier sealants to fill those cuticle gaps. Coconut oil and shea butter prevent moisture from escaping.

Our CURL-DEFINING Duo works across porosity levels because it balances lightweight humectants with nourishing butters. Know your porosity and you can layer products more strategically.

The complete science breakdown is in our comprehensive guide to hair porosity.

Your scalp deserves attention too

We get so focused on hair type that we forget about the scalp—literally where all your hair is coming from. Your scalp can be oily, dry, balanced, or a confusing combination of both.

Day after wash day, dab your scalp with a tissue. Super oily? You might be overproducing sebum or using products that are too heavy. Flaky and tight? Your scalp is crying out for hydration. If you've got both happening at once, you probably have buildup that needs to be clarified away.

Our SCALP HEALTH Shampoo is formulated specifically for dry, flaky scalps—it restores hydration with oatmeal and neem oils while reducing flaking by 1.5x (yes, that's clinically proven).

Putting it all together: creating your perfect routine

So you've figured out you're a 3B curl pattern with medium texture, high density, and low porosity. Now what?

Your hair type gives you a starting point. Your hair might love co-washing when typical advice says it shouldn't. You might need to clarify more or less often than others with similar hair. Pay attention to how your hair responds.

For curly hair (types 3A-3C):

Consistent moisture and gentle handling keep curls healthy. Sulfates strip the limited natural oils these curls retain. Our CURL-DEFINING Shampoo Bar cleanses gently while infusing moisture through cocoa and shea butter.

Deep conditioning isn't optional. The CURL-DEFINING Conditioner Bar contains no silicones—preventing buildup that weighs down curls. Used together, this duo increases coily hair shine by 104% in clinical studies.

Apply styling products to soaking wet hair for better distribution. Experiment with plopping (t-shirt wrapping), diffusing with low heat, or air-drying based on your schedule and what works for your hair.

For coily hair (types 4A-4C):

Tight coil structure prevents natural oil from traveling scalp to ends. Products need to do most of the work.

Deep condition weekly minimum. Masks, rich conditioners, overnight oil treatments—whatever works for your schedule. Low porosity hair? Steam or gentle heat helps products penetrate better.

Detangle gently using fingers or wide-tooth combs. Start at the ends, work your way up. Protective styles help by minimizing manipulation and reducing breakage.

Try both the LOC method (Liquid, Oil, Cream) and LCO method (Liquid, Cream, Oil). One usually works better than the other for sealing moisture. It's worth testing both to figure out which order your hair prefers.

Common mistakes that undermine results

Using straight-hair products on curly textures. Type 1 formulas leave type 4 hair parched and lifeless. Straight and curly hair have different structural needs—different ingredients, different approaches.

Over-washing. Most curly hair functions best with 1-2 washes per week. More frequent washing strips the limited natural oils your hair produces and disrupts scalp balance.

Ignoring porosity. Two people with identical 3A curl patterns need different products if their porosity levels differ. It's one of those factors that seems minor until you account for it—then everything works better.

Applying heavy products to fine hair. Thick, voluminous curls with fine individual strands? They get weighed down by butters and oils. You end up looking greasy rather than moisturized. Check your texture first.

The concentration advantage of solid bars

Traditional liquid shampoos contain 70-80% water. Solid bars concentrate ingredients—typically 10x more actives than liquid shampoos, 15x more than liquid conditioners.

The CURL-DEFINING Shampoo Bar delivers concentrated shea butter, cocoa butter, and glycerine. Key ingredients for curl health, not filler and water.

One duo replaces 8 plastic bottles.

Pro tips from the curly hair community

Refresh between washes. Spray bottle with water and a bit of conditioner revives day-three curls. No full wash needed.

Switch to silk or satin pillowcases. Cotton creates friction that leads to frizz and breakage overnight. Silk or satin preserves your curl pattern while you sleep. Satin bonnets work just as well if pillowcases aren't in the budget.

Trim regularly. Every 8-12 weeks keeps split ends from traveling up the shaft and disrupting your curl pattern. Regular trims maintain bounce and health. Look for a stylist experienced in dry-cutting curls—it's worth finding someone who knows what they're doing.

Adjust with the seasons. That product you loved in summer? Might not work come winter. Hair needs change with humidity, temperature, hormones, and stress. Don't be afraid to modify your routine when favorites stop performing.

FAQs about hair type

Can my hair type change?
Curl pattern is genetic—your follicle shape stays constant. Hormones, medications, pregnancy, and aging affect how curls express themselves. You might notice tightening or loosening during major physiological changes. Heat and chemical damage alter curl patterns temporarily, sometimes permanently with severe damage.

What if I have multiple curl patterns?
Most people do. Use products suited to your most prevalent curl type, then adjust techniques for different areas. You might need to style different sections differently—maybe diffusing some areas and air-drying others.

Does hair length affect curl pattern?
Weight stretches curls as hair grows longer, especially with fine or medium texture hair. Some people notice tighter curls when they cut their hair shorter, though the curl pattern itself hasn't changed—it's just not being pulled down by its own weight anymore.

How often should I wash curly hair?
Depends on your combination of type, density, porosity, and lifestyle. Most curly-haired people wash 1-2 times per week. Some need more. Others can go longer. Monitor your hair and scalp condition instead of following generic schedules.

Making it work for your hair

Knowing your hair profile—curl pattern, texture, density, and porosity—creates a framework for making decisions. Guidelines that help you make informed choices.

Your 4B hair might thrive with co-washing. Your fine 2C hair might need heavier products than typical recommendations suggest. Experiment with our CURL-DEFINING Duo and other techniques. See what happens. Adjust based on results.

Finding what works for your specific combination takes some testing. Worth it, though. Healthy hair that behaves predictably and looks the way you want.

References

1. Nagase, S. (2019). Hair Structures Affecting Hair Appearance. Cosmetics, 6(3), 43. https://doi.org/10.3390/cosmetics6030043

2. Jeong, E. T., et al. (2024). Effects of ultraviolet rays and particulate matter on hair porosity in damaged hair. Journal of Cosmetic Dermatology, 23(6). https://doi.org/10.1111/jocd.16145

3. McMichael, A. J. (2007). Hair and scalp disorders in ethnic populations. Dermatologic Clinics, 25(4), 453-464. https://doi.org/10.1016/j.det.2007.06.006

4. Robbins, C. R. (2012). Chemical and Physical Behavior of Human Hair (5th ed.). Springer. https://doi.org/10.1007/978-3-642-25611-0