What Is HGH? Dosage, Half-Life & How to Track It

What HGH is and how it works

HGH — human growth hormone, generic name somatropin — is recombinant DNA technology’s version of the exact 191-amino-acid protein your pituitary gland naturally produces. Unlike CJC-1295, ipamorelin, or sermorelin, which prompt your own gland to release more GH, somatropin is the hormone: injecting it raises circulating GH directly, bypassing the pituitary and its natural feedback loop entirely.

That distinction matters. Because it skips the body’s own release-and-shutoff cycle, exogenous GH does not arrive in the same clean, natural pulses that GHRH/GHRP protocols aim to mimic — it is present continuously between doses, which is part of why the two approaches are considered different tools with different risk profiles, not interchangeable versions of the same thing.

GH’s downstream effects run largely through IGF-1, produced mainly in the liver in response to GH signaling — most of what people associate with growth hormone (tissue repair, changes in body composition, metabolic effects) is really IGF-1 doing the work. It is FDA-approved for confirmed GH deficiency, several pediatric growth disorders, and HIV-associated wasting; use outside those indications is off-label.

Typical dosing & reconstitution

HGH is supplied as a lyophilized powder and reconstituted with bacteriostatic water. Replacement-style protocols are conservative — starting around 150–200 mcg daily and titrating slowly — while higher-dose metabolic or body-composition protocols run a gradual weekly titration up toward 1,000–2,000 mcg, well above physiologic replacement levels.

Reconstitution volume sets your concentration and, from there, your syringe units:

At ~1.11 mg/mL, a 300 mcg dose is 27 units; the same 300 mcg from a larger multi-dose vial reconstituted the same way is only 9 units. Titration protocols step the dose up by roughly 100 mcg a week, so the units change every week too — the reconstitution calculator recalculates instantly instead of requiring fresh arithmetic each time.

Half-life & what it means for frequency

Subcutaneous somatropin has a half-life on the order of 2 to 4 hours — longer than a GHRP pulse, but nowhere near a weekly-dosed compound. Once-daily injection, generally at bedtime to work with the body’s natural nocturnal GH rhythm, is the standard schedule for both replacement and higher-dose protocols.

Because it is present in the blood for hours rather than minutes, exogenous GH produces a more sustained elevation than a short-half-life secretagogue pulse — part of the mechanistic reason dose-dependent side effects (fluid retention, insulin resistance) tend to track with GH more than with GHRP/GHRH protocols.

What to track & common side effects

HGH’s side effects are real and dose-dependent, which is exactly why it is a prescription medication rather than an over-the-counter supplement. Common ones include water retention, joint stiffness or carpal-tunnel-like symptoms, and — the one worth taking seriously — reduced insulin sensitivity, since GH directly opposes insulin’s effect on blood sugar. Higher, non-replacement doses raise the likelihood and severity of all of these.

Given that risk profile, the things worth tracking closely are the actual dose taken (titration protocols change weekly, and drift is easy), fasting glucose if you are running anything above replacement range, and body-composition or recovery trends — plus IGF-1, the standard lab for confirming a protocol is doing what it is supposed to.

Frequently asked questions