A rapid adolescent growth spurt comes from a coordinated rise in growth-promoting signals, especially growth hormone interacting with thyroid hormones and sex steroids. Growth hormone drives the lengthening of bones by stimulating chondrocyte proliferation at the growth plates and boosting IGF-1, which acts on bone and cartilage to lengthen the skeleton. Thyroid hormones are essential for normal growth and help tissues respond to growth hormone; without adequate thyroid hormone, growth slows even if GH is present. Androgens surge during puberty and markedly accelerate growth by boosting protein synthesis and bone formation, while also increasing the growth plates’ sensitivity to GH and IGF-1. This combination—GH providing the main growth signal, thyroid hormones enabling and sustaining growth, and androgens driving the rapid increase in height during puberty—produces the adolescent growth spurt. Other choices don’t play the primary role: insulin and cortisol aren’t the central drivers of the pubertal growth surge, melatonin is related to sleep, and oxytocin with prolactin are tied to other reproductive or lactational functions rather than the height increase seen in adolescence.