Human growth hormone is not a "peptide" in the short-chain sense most of this
library covers — it is a full protein hormone — but it sits at the center of
the growth-hormone-peptide conversation, so a monograph belongs here.
Chemical identity & structure.
Human growth hormone (hGH) is a 191-amino-acid single-chain protein produced by
the anterior pituitary. The recombinant pharmaceutical form is called
somatropin and is sequence-identical to the endogenous 191-residue hormone.
It is a much larger molecule than the synthetic peptides elsewhere in this
library, which has direct consequences for stability and handling.
Mechanism of action.
Growth hormone acts both directly, via the GH receptor on target tissues, and
indirectly, by stimulating hepatic production of insulin-like growth factor 1
(IGF-1), which mediates many of GH's anabolic effects. GH influences protein
synthesis, lipolysis (fat breakdown), and glucose metabolism. Its secretion is
naturally pulsatile and is regulated by GHRH and somatostatin — a fact that
matters when comparing hGH itself to the GH-secretagogue peptides (ipamorelin,
CJC-1295, tesamorelin) that act upstream.
Key research findings.
The clinical record for somatropin is long. It is an established replacement
therapy for diagnosed growth hormone deficiency in children and adults, and is
approved for several other specific conditions. The literature also documents
the risks of excess GH — fluid retention, joint pain, insulin resistance, and
the consequences seen in acromegaly — which is why GH is dosed clinically to a
physiological target, not maximized.
The research / citation base.
Somatropin is FDA-approved and has decades of clinical use and published trial
data behind it for its approved indications. Evidence for non-approved uses
(for example, anti-aging or athletic use) is weak to absent, and such uses are
not supported by the clinical literature.
Human clinical trial data
In the randomized phase 3 REAL 1 trial by Johannsson et al. (2020), treatment-naive adults with GH deficiency were randomized 2:2:1 to once-weekly somapacitan (a long-acting GH derivative), daily GH, or once-weekly placebo for a 34-week main period, followed by a 52-week extension; in that trial, IGF-I SDS values were used to dose titrate (PubMed). The trial reported that somapacitan reduced truncal fat percentage versus placebo, with adverse events similar to daily GH (PubMed). hGH is heat- and agitation-sensitive and requires careful cold-chain handling.
Quality & sourcing notes.
Because hGH is a large protein, identity and purity verification is more complex
than for short peptides — a credible COA involves more than a single HPLC trace.
Counterfeit hGH, and product mislabeled as hGH that is actually a cheaper GH-
secretagogue peptide, are both documented problems. Verify the supplier and the
batch documentation carefully.
*Research-use note: Educational summary of published research. Somatropin is a
prescription drug; this monograph is research context only and is not medical
advice.*