Tanner Stages (also known as the Sexual Maturity Rating ), which track physical maturation from prepuberty to adulthood [4, 5, 11]. Stage 1 (Pre-pubertal): No visible external changes, but hormones are beginning to activate internally [4, 16]. Stage 2 (Puberty Onset): Initial physical signs appear—breast budding (thelarche) in girls and testicular enlargement in boys [4, 5, 26]. Stage 3 (Growth Acceleration): Physical changes become more obvious; pubic hair thickens, and a significant growth spurt begins [3, 4, 11]. Stage 4 (Peak Maturation): In girls, menarche (first period) typically occurs. In boys, the voice deepens permanently and the penis continues to grow [3, 4, 16]. Stage 5 (Adult Maturity): Final adult height and full reproductive development are reached [4, 11, 25]. Key Physical Changes Growth Spurt: A rapid increase in height and weight. Girls typically experience this earlier (Stage 2-3), while boys hit their peak later (Stage 3-4) [1, 4, 11]. Body Composition: Boys generally gain more muscle mass and lose fat in their limbs, while girls experience an increase in body fat, particularly in the hips and breasts [2, 5, 17]. Skin and Hair: Increased oil production leads to
Reviewing the clinical landscape requires distinguishing between normal variations and pathology: pubertal development
Future research must prioritize the environmental factors driving earlier puberty and the long-term health consequences of this shift. Understanding that the adolescent brain is structurally distinct—and not merely an adult brain "high on hormones"—is essential for parents, educators, and clinicians navigating this turbulent transition. Tanner Stages (also known as the Sexual Maturity
is released by the hypothalamus.