Type 4 hair, and what a salon needs to know
The type number tells a stylist less than most people assume. Here is what it does describe, what it leaves out, and what to ask before you sit in the chair.
Where the numbers came from
The type system runs from 1 to 4, straight through to coily, with a, b and c subtypes. It was popularised in the 1990s by the stylist Andre Walker, and it was built alongside a product range rather than as a clinical classification. That origin matters, because it explains what the system is good at and what it is not.
It is a reasonable shorthand for curl diameter. It is a poor guide to what a head of hair actually needs. 4c is the clearest sign of the strain: it was not in the original system and came out of natural hair communities online, which is why definitions of it still vary depending on who you ask.
4a, 4b and 4c
- 4a coils in a defined spiral, roughly the width of a crochet needle, and usually shows its pattern when wet without much help.
- 4b bends more sharply than it curls, closer to a zigzag, and reads as less defined even when it is perfectly healthy.
- 4c has the tightest pattern and the least visible definition, and it is the one most often mistaken for damage when it is nothing of the sort.
Most heads carry more than one of these, often with a looser pattern at the nape or the crown. A stylist who treats a whole head as one number is going to get part of it wrong.
Shrinkage is not length
Type 4 hair can appear up to about three quarters shorter than it is. That single fact causes more bad salon appointments than anything else on this page. It is why a length check on dry, unstretched hair is close to meaningless, and why someone can leave a chair convinced they have been cut short when almost nothing came off.
Porosity tells you more than type
Porosity describes how readily the cuticle takes in moisture and how quickly it loses it. It is the more useful number in practice, because it drives product choice directly, and two people with identical curl patterns can need opposite routines.
- Low porosity resists water going in. Product sits on top, and heavier butters tend to build up rather than absorb.
- High porosity takes water in quickly and loses it just as fast, so sealing matters more than soaking.
Density, meanwhile, is how many strands are on the head, and it is unrelated to both. Thick hair and coarse hair are not the same thing, and conflating them is how people end up with products that weigh their hair down for years.
What a salon that knows this hair does differently
- Detangles with slip and patience, wet or damp with conditioner in, working from the ends up rather than the roots down.
- Sections properly. Four sections is not sectioning.
- Has a stated heat policy rather than an improvised one.
- Braids and installs without the tension that causes traction alopecia at the hairline, which is cumulative and, past a point, permanent.
- Says no to a style that the hair in front of them cannot currently take.
Worth asking before you book
- How often do you work on hair like mine, rather than can you work on it.
- Can I see finished work on a similar texture, not a similar length.
- What is your heat policy, and what temperature do you actually use.
- Will you detangle dry or with conditioner in.
- If my hair cannot take the style I have asked for, will you tell me.
The last one is the real test. A salon that has never turned a style down is a salon that has never protected anyone's hairline.
Why we built the map around this
Searching for a salon near you tells you where one is. It does not tell you whether anyone there has worked on your texture, and that is the only thing you actually needed to know. On FSHNiSTA a salon claims a specialism and shows the work behind it, so the search runs on what they do rather than where they are.