Can height gain be possible after 18 for a female by changing diet and sleeping well with high HGH levels? How can I lengthen my spinal column?

If no growth last yr. An 18 yr old is not growing taller if her growth plates have fused. If not fused, she may grow a tiny bit (pediatrician's growth chart for her can tell if growth has stopped). To look taller, one can choose properly designed clothing ; shoes, and have good posture. Vitamins, supplements, "special" foods, extra exercise, etc... Will not make her taller if she already closed her growth plates.