Human Growth Hormone (HGH) is secreted by the pituitary gland and drives tissue growth, repair, and metabolic function throughout life. After age 30, GH secretion declines approximately 1–2% per year — by 40, most adults have only half the GH output of their peak. By 60, it's roughly 25%.
IGF-1 (Insulin-Like Growth Factor 1) is the primary downstream mediator of GH's effects — produced in the liver in response to GH stimulation, it drives cellular growth, protein synthesis, and fat metabolism. IGF-1 is measurable in blood and is the primary marker we use to assess GH status.
Clinical studies show that GH-secretagogue peptides (CJC-1295 + Ipamorelin) increase IGF-1 levels by 30–60% in adult patients with age-related GH decline — with effects on body composition, sleep quality, and recovery time measurably superior to placebo.
At Body Symmetry MD, we prefer peptide-based GH optimization over direct HGH injection for most patients because peptides stimulate the pituitary's own natural pulsatile release pattern — which is both safer and produces more physiologically appropriate IGF-1 levels than direct HGH injection.