First-degree alopecia: hairline is slightly or normally receding, and the number of transplant units is 1000- 1500.
Secondary alopecia: the hairline moves backward, the forehead is slightly higher, and the hair on both frontal angles falls off to form a small M shape, and the number of transplant units is 1500-2000.
Third-grade alopecia: the hairline recedes obviously, and the hair loss of both frontal angles increases, generally large M type or small C type, and the number of transplant units is 2000-3000.
Fourth-grade alopecia: the forehead is obviously bald, and the whole top of the head is sparse, but the hair does not completely fall off, which is U-shaped, or M+C, C+O, and the number of transplant units is 3000-4000.
Five-level alopecia: all the hair on the top of the head falls off forward or is sparse and obvious, with a broken belt in the middle. The number of transplant units is 4000-5000.
Grade 6 alopecia: the forehead falls off completely, the top of the head moves backward obviously, which is not suitable for hair transplantation and the donor is insufficient.
Grade 7 alopecia: only a circle of long hair is left in the occipital region, which is not suitable for hair transplantation and the donor is insufficient.