Puberty is a critical bone mineralisation period, and peak bone mass attained by adolescent girls is one of the most significant predictive factors for postmenopausal osteoporosis. Adolescent girls’ peak bone mass depends on genetic factors as well as on general condition, nutritional status and body mass; lifestyle is also important, along with physical exercise and the use of prescription drugs. Additionally, hormones, including oestrogens, play an important role during pubertal accumulation of bone mass. Therefore, oestrogen deficiency during puberty has serious consequences for bone mineralisation. During puberty, particularly during the initial years after menarche, hypothalamic dysfunction can develop due to psycho-emotional burden, excessive physical exercise or increasing number of responsibilities; psychologists refer to this period as the “crisis of adolescence”. Its symptoms include behavioural disorders and juvenile depression, both affecting the hypothalamic neurosecretion to an extent that can be reflected by secondary hypo-oestrogenism and amenorrhea. The administration of oestroprogestagens in the treatment of low bone mineral density and hypo-oestrogenism-associated menstrual disorders results in resumed regular menstrual bleedings and maintains, or even improves, bone mineral density. This observation seems to be important not only in terms of short term clinical applications, but also in the context of the long term prevention of osteoporosis. Consequently, hormonal therapy has to be accompanied by a thorough education of patients and their parents, particularly in terms of proper nutrition and modification of levels of physical activity. Puberty is the optimal time period for modifying environmental factors that are associated with bone mass gain. (Pol J Endocrinol 2011; 62 (6): 538–546)