Type 1: Straight Hair
Straight from root to tip, no wave forming at any point — this is the type 1 family: its pattern, its three subtypes, and the care logic that follows from a straight strand.
The pattern
The strand falls straight from root to tip with no bend, wave or curve anywhere along its length. The check that settles it is the dry one: air-dried, type 1 hair hangs flat and straight with no wave forming at any point. If your hair does that, you are on this page’s strip.
The three subtypes
Within type 1 the letters step through substance rather than curl:
- 1a is completely straight, fine and wispy, with no body to it.
- 1b is straight with more body and volume, sitting at a medium texture.
- 1c is straight but thick or coarse, and allows itself a few subtle bends.
The care logic
Because scalp oil travels easily down a straight strand, this family gets oily fastest. That is why the convention runs the way it does: frequent washing, lightweight products, and nothing heavy enough to weigh the hair down. The logic follows the geometry — a straight strand is simply an easy road for oil to travel.
Density is a separate question
Density is how many individual strands grow per area of scalp, which is separate from how thick each single strand is. The conventional reading is the ponytail test: gather dry hair into a ponytail and measure its circumference. Under about two inches reads as low density, two to three inches as medium, and four inches or more as high. Any of the three subtypes can sit at any density.
A note on the letters
1a, 1b and 1c are positions on a strip, not grades. A fine, wispy 1a and a coarse 1c are both fully, equally type 1 — the letter simply tells you which drawn strand above is yours.