Growth during puberty does not appear to be the major determinate of final height in isolated GH deficient patients. Early diagnosis and commencement of therapy are probably the most important factors, as reflected by the correlation between final height and height at the onset of puberty. The cost effectiveness of increasing the dose of GH during puberty does not appear to represent any advantage from the data presently available. Indeed, such an approach may have a deleterious effect on final height by shortening the duration of pubertal maturation. Further prospective studies are required to demonstrate the effectiveness of manipulating the onset and duration of puberty using gonadotrophin releasing hormone analogues on final height in isolated GH deficiency.