Coily hair: 4A, 4B and 4C

Type 4 hair coils tightly from the root. It looks thick and strong, but it is the most fragile pattern: every bend in the strand is a spot where it can break, and it loses moisture faster than any other type.

Shrinkage is part of it. Coily hair can look a fraction of its real length when dry, which is why length retention, not growth, is what most 4-type routines are built around.

4A hair

Small, defined coils with a visible S-pattern when stretched, about the width of a crochet needle. Holds moisture a bit better than 4B and 4C, and wash-and-go styles define well.

What helps: a cream leave-in and a gel for definition, applied on wet hair in small sections.

4B hair

Coils that bend in sharp, Z-shaped angles rather than spirals, so the pattern is less defined. High shrinkage, fluffy texture, and tangles that form quickly at the ends.

What helps: stretched styles such as twist-outs and braid-outs, a thicker cream, and sealing with an oil or butter.

• Cantu Argan Oil Leave-In Conditioning Repair CreamThick cream leave-in. No drying alcohols and no silicones.
• Mielle Pomegranate & Honey Leave-In ConditionerFormulated with curly hair in mind: pomegranate, honey and babassu oil.
• Tropic Isle Living Jamaican Black Castor OilHeavy oil for sealing ends or a hot oil treatment.

4C hair

The tightest coils, often with little visible pattern unless the hair is stretched or styled. The most shrinkage and the most prone to dryness and breakage. Density varies a lot; 4C hair is not always thick.

What helps: everything below, done consistently. Moisture, careful detangling, low manipulation and protective styles worn correctly.

Washing and moisture

The American Academy of Dermatology says thick, curly or textured hair should be shampooed when needed, at least once every 2 to 3 weeks; daily or weekly washing isn't necessary. Many people with type 4 hair wash once a week or every other week, and a pre-wash oil or conditioner treatment ("pre-poo") keeps shampoo from drying out the lengths. Condition the full length after every wash.

Between washes, moisture comes from water-based leave-ins, sealed with an oil or butter: the LOC (liquid, oil, cream) or LCO (liquid, cream, oil) method. Which order works depends on your porosity; try each for two weeks.

Detangling without breakage

Detangle only on wet hair with conditioner in, in sections, from the ends up, with fingers or a wide-tooth comb or a brush made for coily hair. The AAD's advice is the same as for curls: never brush hair when it is dry.

Protective styles, done safely

Braids, twists, locs, wigs and weaves reduce daily handling, but tension at the root causes a type of hair loss called traction alopecia. The AAD's guidance:

• Loosen braids, especially around the hairline, and keep cornrows from being tight.
• Choose thicker braids and locs, and keep them short: longer hair is heavier and pulls more.
• Wear braids for no longer than 6 to 8 weeks.
• Wear weaves and extensions for short periods, remove them right away if they hurt or irritate the scalp, and choose sewn-in over glued.
• Change styles regularly so the hairline can recover.

Pain, bumps or thinning at the edges are a signal to take the style out and, if it continues, to see a dermatologist.

At night

Cotton pulls moisture out of coily hair and creates friction. Sleep in a satin or silk bonnet or scarf, or on a satin pillowcase, with the hair in loose twists or a pineapple.

• Kitsch Satin Pillowcase with ZipperSatin causes less friction than cotton. The zipper keeps it from sliding off.

Two people with 4C hair can still need opposite products, depending on porosity and how much heat or color the hair has had. The quiz builds a routine from all of that.

Sources: American Academy of Dermatology, Tips for healthy hair, 6 curly hair care tips from dermatologists and Hairstyles that pull can lead to hair loss. Pattern descriptions: hair type chart.