HGH

HGH, known by its pharmaceutical name somatropin, matches the hormone that the pituitary gland makes on its own; modern supplies are grown using recombinant technology so the resulting molecule is chemically identical to what the body produces naturally. Regulators have cleared it for a specific set of medical conditions, most involving some cause of growth hormone deficiency, and its use requires a doctor's oversight. Apart from those cleared uses, scientists have looked separately at wider, unapproved applications touching metabolism and how the body is composed.

What it is

Human growth hormone, or HGH, also known by its pharmaceutical name somatropin, is a single protein chain of 191 amino acids that the pituitary gland, a small gland at the base of the brain, produces naturally throughout life. Recombinant HGH is grown in engineered cells rather than extracted from human tissue, and its structure is identical to the hormone the body already makes.

HGH acts on growth hormone receptors found throughout the body, triggering effects on growth, metabolism, and body composition both directly and indirectly, by prompting the liver and other tissues to produce a related growth factor called IGF-1. It is approved for a specific, defined list of conditions, including several causes of a shortfall in growth hormone among both children and grown adults, certain genetic growth disorders, and HIV-associated wasting, all requiring physician diagnosis and supervision.

How it is studied

HGH has an extensive clinical research record built over several decades, including large, long-term observational safety studies following thousands of patients treated for approved conditions and systematic reviews of randomized trials looking at its effects on heart-related measurements and bone health. Separate, smaller research has looked at broader, off-label uses in body composition and aging outside its approved indications, though that body of research is considerably thinner than the record supporting its approved medical uses.

What studies report

In an international registry following 15,809 adults treated with HGH for a confirmed growth hormone deficiency for an average of 5.3 years, new cancer cases overall were about as common as in the general population, and were significantly less common in the group whose deficiency had no identified pituitary tumor cause. [johannsson-2022]
A systematic review of studies on adults with growth hormone deficiency concluded that HGH treatment likely benefits heart-disease risk markers and fracture risk, and did not find fatal or nonfatal cancers to be more common in treated adults than in the general population, though the authors noted the available follow-up time was still relatively short. [vanbunderen-2014]
A review describing the clinical picture of growth hormone deficiency in adults reports that the untreated condition is marked by changes in body fat and muscle, reduced exercise capacity and quality of life, and unfavorable changes in heart-related and blood-sugar measurements, and that HGH replacement improved fracture risk, blood fat levels, body composition, and quality of life at commonly used amounts with a low rate of side effects. [cotta-2024]

What is not known

The research base for HGH's approved uses is substantially larger and better controlled than the research base for off-label uses in body composition or aging in otherwise healthy adults, and the balance of benefit and risk for those off-label uses is not established with the same confidence. Even within the approved-use safety data, the studies reviewed here relied on long-term observation of treated patients rather than placebo-controlled trials of a size needed to rule out smaller changes in cancer or stroke risk, and follow-up beyond roughly five to ten years is limited.

Regulatory status

HGH is approved by the United States Food and Drug Administration for a specific list of conditions, including growth hormone deficiency and several related growth disorders, under physician prescription. Use for any purpose outside those approved conditions is considered off-label. It is prohibited by the World Anti-Doping Agency in competitive sport.