IsItClean
Type 1 · Straight

1C Hair

Coarse, thick straight hair that frizzes easily. Type 1C hair is the thickest, coarsest straight hair type — straight but prone to frizz and a slight wave underneath. Learn how to identify 1C hair and build a routine that smooths without weighing it down.

Build my 1C routine

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How do I know if I have 1C hair?

Your hair looks straight but feels coarse and thick between your fingers, and you get frizz or a faint wave at the nape and around the hairline. It resists curling but also resists lying perfectly flat, and humidity makes it puff.

Key characteristics of 1C hair

  • The thickest, coarsest strand diameter in the Type 1 family
  • Straight overall with occasional waves underneath or at the nape
  • Prone to frizz, especially in humidity
  • Holds a curl better than 1A or 1B
  • Less oily at the roots than finer straight types

The one thing 1C hair struggles with most

Frizz. Type 1C has a thicker cuticle that lifts easily, so moisture in the air gets in and the strand swells. Straightening is the usual fix, which then adds heat damage on top of the frizz.

What 1C hair needs

  • Smoothing serum or lightweight oil on mid-lengths and ends
  • Weekly moisture mask — coarse strands lose water faster than fine ones
  • Anti-humidity finishing product in damp climates
  • Heat protectant, since 1C often gets straightened

What 1C hair should avoid

  • Harsh sulfates, which strip coarse hair and trigger frizz
  • Skipping conditioner because the hair "looks fine"
  • Brushing dry — it roughs up the cuticle and creates frizz
  • Alcohol-heavy styling sprays

1C hair and porosity

1C hair is often normal-to-high porosity, especially if it has been heat-styled or coloured. High porosity means it soaks up water fast and loses it just as fast, so sealing with an oil after conditioning matters.

Take the free porosity test Check a product's ingredients

Get a routine built for 1C hair

Knowing your type is the first half. The quiz covers the other half — your porosity, scalp condition, damage level, and which ingredients your hair does not tolerate — then builds the routine around all of it.

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Other straight hair types

1A Hair

Fine, pin-straight hair with no natural bend

1B Hair

Straight hair with medium texture and more body

Keep reading

All 12 hair types explained Hair type quiz Hair porosity test