Malnutrition can be a significant problem for some adolescent males. In the United States, the most common causes of malnutrition in this age range include serious gastrointestinal disease, like inflammatory bowel disease (Crohn's disease or ulcerative colitis), and eating disorders.
When malnutrition occurs in adolescents, the most likely effect will be that it will delay the onset of puberty. If the underlying cause of the malnutrition is caught in time and treated appropriately, most males will go on to have normal pubertal development, assuming that they remain adequately nourished. However, in some severe cases, the development of normal features associated with puberty may be permanently altered. This, in particular, tends to affect the impairment of adult stature (how tall someone is). Also, in some cases, chronic inflammation associated with some forms of malnutrition (inflammatory bowel disease, for example) may permanently decrease the production of testosterone, leading to trouble with secondary sex characteristics, like facial hair patterns.
If these are issues that you are dealing with, then you need to discuss them as soon as possible with your doctor
. You could start with your pediatrician
, although if delayed puberty is a significant problem you will probably also need to see a pediatric endocrinologist