A child with GHD is usually of normal size at birth. A few children may become hypoglycemic (low blood sugar) during the newborn period. Males may have a small penis (micropenis). Later, children with GHD may present with delayed rates of development of facial bones, slow tooth eruption, delayed lengthening of long bones, fine hair, and poor nail growth. They may also demonstrate truncal obesity, a high pitched voice, and delayed closure of the sutures of the skull, causing delayed closure of the fontanelles.

Growth increments are the most important criteria in the diagnosis of GHD in children. Normal levels of growth usually follow a pattern, and if growth during a recorded six to twelve month period is within those levels it is unlikely that a growth disorder exists.

Growth in the first six months of life is usually 16 to 17 cm and in the second six months approximately 8 cm. During the second year 10 cm or more is normal. Growth in the third year should equal 8 cm or more and 7 cm in the fourth year. In the years between four and ten, an average of 5 or 6 cm is normal. A 10% decrease in these growth rates can result in an insufficient growth velocity, and thus a noticeable decline on the growth chart. When that is recognized, even before the child has fallen to a significantly low percentile (1.2% = -2 SD), he/she should then be tested for abnormally low levels of growth hormone.

An individual who acquires GHD later in life presents more generalized symptoms. They may notice a relative increase in fat mass, especially abdominal and visceral, along with a decrease in muscle mass. Decreased energy levels, anxiety, and/or depression are also common. Lipid levels are also affected, resulting in an increase in LDL-cholesterol and triglyceride levels.