Why transplanted hair looks darker specially on the hairline?

It is not possible to say why your hair looks darker.  If your donor hair is dark then it will look dark where it has been transplanted.

RayanSaman,The hair in the back of the head is the last to grey so if it is transplanted darker hair will grow in the transplanted area. Also since hair on sides and top get more Sunshine, they tend to be high lights, which are not present in the hair that is transplanted from the back.All the best,Bernardino A. Arocha, MD

The transplanted hair should look the color of the hairs in the back of the head not in the front where the hairs are miniaturized in normal male balding