An adjustment mechanism for a headrest for a seat has a scissor lever. The adjustment mechanism has at least one first lever arm and at least one second lever arm. A compensating lever arm is arranged at at least one lever arm end of each lever arm. A free end of each compensating lever arm has an attachment structure for attaching the compensating lever arm to a body. A lever arm end opposite the compensating lever arm of each lever arm has an attachment structure for attaching the lever arm to a body. A headrest for a vehicle seat, which has a headrest body is also provided.