"Initiation and Monitoring of GH Treatment
Unlike pediatric GH treatment, often dosed in micrograms/kilograms of body weight/day, currently recommended GH replacement dosing in adults is individualized independent of weight, taking into account the patient’s age, gender, and estrogen status (Johannsson et al., 1997a; Hoffman et al., 2004b). Initiating therapy at low doses (total dose 0.2–0.4 mg/day SC) decreases the likelihood of developing common side effects like joint stiffness, arthralgias, myalgias, paresthesias, and peripheral edema, with fluid retention. The dose should be titrated at 6–8 week intervals based on clinical response, while avoiding side effects and monitoring serum IGF-I levels. Achieving a target in the upper half of normal age adjusted IGF-I range is desired. It is reasonable to start with higher doses (0.4–0.5 mg/day) in patients less than 30 years of age, but older patients (greater than 60 years of age) should be started on lower doses (0.1–0.2 mg/day) and titrated more slowly to minimize occurrence of side effects."
Reference:
Deficiency of growth hormone (GH) in adults results in a syndrome characterized by decreased muscle mass and exercise capacity, increased visceral fat, impai...
www.frontiersin.org
My experience lines up very well with the clinical observations and recommendations. Even for people under 30 they don't recommend 2iu a day (0.66mg).