Recombinant human growth hormone — clinically approved for specific deficiencies, frequently misused for anti-aging. Here’s how it actually works and what responsible access looks like.
Human growth hormone (HGH, somatropin) is a 191-amino-acid recombinant protein produced by DNA technology to match endogenous pituitary growth hormone. It’s sold under brand names including Genotropin, Humatrope, Norditropin, Omnitrope, and Saizen.
HGH is prescription-only in the US and FDA approved for specific indications: adult and pediatric growth hormone deficiency, certain short-stature syndromes, HIV-associated wasting, and short bowel syndrome. Prescribing HGH for anti-aging or athletic enhancement is illegal under federal law.
FDA approved for defined indications. Not a DEA-scheduled controlled substance, but distribution for any use other than an FDA-approved indication is a federal crime under 21 USC §333(e), punishable by up to 5 years imprisonment. WADA prohibited (S2.1). StackTrax does not sell or facilitate HGH.
Binds GH receptors primarily in the liver and peripheral tissues. Liver response produces IGF-1, which mediates most of the anabolic and metabolic effects downstream.
Serum IGF-1 is the primary measured outcome of HGH therapy and the standard biomarker for titration (Endocrine Society 2011, PMID 21602453). It's the key driver of muscle growth, tissue repair, and bone density effects.
HGH directly stimulates fat breakdown in adipose tissue via its own receptors — independent of IGF-1. This is a mechanism secretagogues (sermorelin, CJC+Ipa) preserve.
Exogenous HGH suppresses the pituitary’s own pulsatile GH output via IGF-1 negative feedback on the somatotropic axis (hypothalamic GHRH → pituitary GH → liver IGF-1). This is why GH secretagogues (which stimulate your own pituitary) have become the preferred approach for non-deficient patients.
The feedback is measurable, and it is not uniform across secretagogues. Veldhuis 2004 (PMID 15531509) gave 17 healthy men rhIGF-I, then challenged them with GHRH or GHRP-2. Secretagogue type independently determined the GH response (p < 0.001) with a strong three-way interaction between age, secretagogue and IGF-I (p < 10⁻⁵). Practically: raising IGF-1 blunts the response to a later secretagogue dose, which is the mechanism behind the standing advice not to run HGH and a secretagogue together.
The 86% / 32% figures often quoted alongside this are real, and they come from Arvat 1997 (PMID 9005975). Six healthy volunteers received 2 U of rhGH intravenously, then a GH-releasing challenge. The GH response to GHRH was nearly abolished — 86.1% inhibition, while the response to hexarelin was only blunted, 32.1%. That asymmetry is the real finding: a GHRH analogue (sermorelin, CJC-1295, tesamorelin) is almost entirely shut down by circulating GH, whereas a ghrelin-receptor agonist substantially survives it.
Two details usually dropped in the retelling. The ghrelin-side compound tested was hexarelin, not ipamorelin — applying the 32% figure to ipamorelin specifically is an extrapolation. And the combination held up far better than either alone: GHRH plus hexarelin was inhibited only 26.7%, and when pyridostigmine was added the combination was not blunted at all. The blanket claim that secretagogues are useless on GH is stronger than what this study actually shows.
| Benefit | Evidence |
|---|---|
| GH deficiency | Gold-standard: restores normal growth in children, normalizes body composition and metabolism in adults (Molitch 2011, PMID 21602453) |
| Lean mass / fat loss | Measurable in deficient adults; in healthy adults Liu 2008 (PMID 18347346) found body-composition shifts but no improvement in strength or aerobic capacity, with elevated AE rates |
| Recovery / repair | IGF-1 promotes anabolic signaling in injured tissue (satellite-cell activation, collagen synthesis) — the mechanistic basis for the "recovery" framing in clinical literature |
| Sleep quality | Endogenous GH peaks during slow-wave sleep; the relationship is bidirectional. Exogenous HGH does not reliably improve sleep quality and may flatten the natural pulse |
| Bone density | Long-term BMD improvements in deficient patients on extended replacement (Johannsson 2022 KIMS, PMID 35368070). Götherström 2007 (PMID 17284638) followed GH-deficient adults for a full 10 years, starting near 0.72 mg/day and settling around 0.37 mg/day for maintenance, with sustained body-composition and strength gains |
| Anti-aging (off-label) | Rudman 1990 (PMID 2355952) reported +8.8% lean mass, −14.4% fat mass, +7.1% skin thickness and +1.6% lumbar bone density in 12 men over 60 — but had no placebo arm, no strength or QoL endpoints, and was disavowed by NEJM in a 2003 editorial (Vance, PMID 12606731). The definitive follow-up is Liu 2007 (PMID 17227934), a systematic review of 18 RCT populations and 220 GH-treated participants: fat mass fell 2.1 kg (95% CI −2.8 to −1.35) and lean mass rose 2.1 kg (CI 1.3 to 2.9), with higher rates of oedema, carpal tunnel, arthralgia and gynaecomastia. The authors concluded GH cannot be recommended as an anti-aging therapy — and noted its distribution as an anti-aging agent is illegal in the United States |
For non-deficient adults seeking GH-pathway benefits, growth hormone secretagogue peptides (sermorelin, CJC+ipamorelin, tesamorelin) offer most of the upside with fewer side effects and without axis shutdown.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeIGF-1 is the biomarker every GH protocol titrates against, and the common assumption — more is better — is contradicted by the largest prospective dataset on the question.
Mukama 2023 (PMID 37066827) measured IGF-1 in 7,461 stored serum samples from the EPIC-Heidelberg cohort and followed participants for a median of 17.5 years, covering 1,668 incident cancers, 1,428 cardiovascular events and 2,441 deaths. Restricted cubic splines showed a U-shaped relationship between IGF-1 and mortality: participants in both the lowest and the highest bands had elevated hazards of death from cancer, cardiovascular disease and all causes. Higher IGF-1 also carried direct associations with breast cancer (HR 1.25, 95% CI 1.06–1.47) and prostate cancer (HR 1.31, 1.09–1.57).
The U-shape persisted, though attenuated, when the analysis was restricted to participants with no sign of liver dysfunction — which matters, because low IGF-1 can be a marker of liver disease rather than a cause of anything.
Two things follow. Driving IGF-1 toward the top of the reference range is not a free upgrade; it is a move toward the far arm of a curve where mortality rises again. And this is precisely why the Endocrine Society guideline titrates to the middle of the age- and sex-adjusted reference range rather than the upper limit (PMID 21602453). Anyone treating a high-normal IGF-1 as a scoreboard has the wrong scoreboard.
This applies to the secretagogue peptides too, not just injected HGH — anything that raises IGF-1 lands somewhere on the same curve.
Not medical advice. These are prescription medications. The figures below describe established clinical practice and labelled prescribing information — they are not a recommendation, they do not account for your labs, history, or other medications, and safe use depends on monitoring a page cannot do. Work with a qualified healthcare provider.
Per Endocrine Society 2011 (PMID 21602453); the guideline cautions against driving IGF-1 to the upper limit. AACE/ACE 2019 (Yuen, PMID 31760824) recommends age-stratified starting doses — younger adults may start higher (0.4–0.5 mg/day under 30).
This is a starting range, not a destination. GH is titrated to IGF-1, not held at a fixed milligram figure, and the dose that patients actually settle on is usually higher than where they begin. The longest published follow-up illustrates the shape: in the 10-year prospective study (PMID 17284638), 87 adults with GH deficiency started at a mean 0.98 mg/day and were titrated down over the decade to 0.47 mg/day by year 10, with IGF-1 SD score moving from −1.81 at baseline to +1.29 at the end. Expect the number to move in both directions as labs come back.
Some integrative clinics use 1–2 IU/day in older adults. These ranges have no support in FDA labels or major society guidelines, and Liu 2008 (PMID 18347346) found supraphysiologic GH in healthy adults produces body-composition shifts without strength or aerobic gains, with elevated AE rates. Peptide alternatives (CJC+Ipa, tesamorelin) are increasingly preferred at this dose range.
GH acts on fat directly through its own receptor, but its anabolic effects run largely through IGF-1, and the liver needs insulin present to convert GH into IGF-1 efficiently. That gives injection timing a real mechanistic logic rather than a folk one. Dosing fasted and staying fasted favours the direct lipolytic action; dosing and then eating within 30–60 minutes gives the liver the insulin it needs to make IGF-1. Evening dosing sits closest to the natural nocturnal pulse. None of this is a substitute for getting the dose right, and no trial has compared these schedules head to head.
4–8 IU/day. Physique-driven use runs several times the replacement range. Nothing in the published record supports it for health, and the side-effect profile at that level — insulin resistance, fluid retention, joint pain, organ growth over time — is not the profile seen in the 1–2 IU trials.
HGH with insulin. Used to offset GH’s anti-insulin effect and push IGF-1 conversion. The hypoglycemia risk here is the kind that kills people, there is no published safety data for the combination, and it has no place in a health-optimisation protocol.
HGH alongside secretagogues. Covered above — the pituitary is suppressed while you pay for compounds to stimulate it. Running CJC+Ipa to “protect the pituitary” during HGH use does not work by the same mechanism.
IGF-1 (primary), fasting glucose, HbA1c, lipids, thyroid panel. Many providers also monitor IGFBP-3. Frequency: baseline, 6–8 weeks after starting or adjusting, then every 3–6 months (Endocrine Society 2011, PMID 21602453).
Why the thyroid panel is on that list. It is not routine box-ticking. GH replacement shifts the thyroid axis and can unmask central hypothyroidism that was masked before treatment (PMID 17201804), with free T4 falling after GH is started (PMID 20455887). Someone whose thyroid looked fine at baseline can become genuinely hypothyroid on GH and read it as the fatigue and puffiness of a dose that is too high.
On IGF-1 targets. A target band of 120–175 ng/mL circulates widely in optimisation circles. Treat it as a rule of thumb rather than a number to chase: IGF-1 reference ranges are assay-specific and fall steeply with age, so the same 150 ng/mL is mid-range for one person and high for another. Titrating to the middle of your age- and sex-adjusted reference range is what the guideline actually asks for, and it is the more defensible target.
Pre-filled with a typical HGH / Somatropin setup. Edit any field — the draw updates live.
Insulin syringe — 100 units = 1 mL
Free account. Saves your reconstitution + schedules doses + tracks every vial.
Dosing cheat sheet, reconstitution reference, and cycle planning — delivered to your inbox.
Not medical advice. These figures describe what is reported in the literature and what practitioners and communities do — not a recommendation, and for most compounds here no human dose-finding study exists. Talk to a qualified healthcare provider.
FDA-approved HGH is dispensed as pre-filled pen cartridges (Genotropin, Norditropin, Humatrope pens) or multi-dose vials with dedicated diluent. Unlike research peptides, you do not reconstitute with bacteriostatic water — the manufacturer’s diluent is the only appropriate reconstitution fluid.
HGH elevates IGF-1. Active malignancy is an absolute contraindication. History of malignancy is a relative caution — current consensus (GHRS 2022, Boguszewski, PMID 35319491) supports individualized risk-benefit assessment with the treating oncology team. In childhood cancer survivors, a small second-neoplasm signal (largely meningioma after cranial radiation) has been reported (He 2022 meta-analysis, PMID 35529328).
HGH / Somatropin is a prescription medication. StackTrax does not sell, prescribe, or facilitate purchase of prescription drugs.
Find a clinician who can order baseline lab work, screen for contraindications, monitor your response, and adjust dosing over time. Options to consider:
Before starting, you’ll typically want:
Avoid sources that offer prescription medications without labs, medical history, or licensed-provider oversight. If a telehealth service promises a prescription after a 5-minute questionnaire, that’s a red flag.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeYes — for defined indications only. Recombinant somatropin is FDA approved for pediatric growth hormone deficiency, adult GHD, Turner syndrome, Prader-Willi syndrome, idiopathic short stature, short bowel syndrome, AIDS wasting, and several other rare indications. Brand names include Genotropin, Norditropin, Humatrope, Saizen, Omnitrope, Zomacton, Skytrofa (lonapegsomatropin, long-acting), Ngenla (somatrogon), and Sogroya (somapacitan). Off-label use for anti-aging, body composition, or athletic enhancement is NOT FDA approved and carries legal risk: distribution of HGH for non-approved uses is restricted under 21 USC §333(e), which classifies non-prescribed HGH distribution as a federal offense punishable by fines and imprisonment.
Approved adult GHD label dose is approximately 0.2 mg/day subcutaneously (Genotropin), titrated to IGF-1 levels. Community off-label "anti-aging" doses commonly cited are 1–4 IU/day (approximately 0.33–1.3 mg/day, given the 3 IU = 1 mg conversion). Higher community doses (5+ IU/day) sit well above the approved adult GHD label and substantially increase side effect risk (insulin resistance, edema, carpal tunnel, joint pain).
Reconstitution depends heavily on the specific product — most FDA-approved pen presentations come with their own diluent and procedure (do NOT use community BAC-water protocols on prefilled pens). For loose-vial research-grade HGH (typically 10 IU per vial): 10 IU + 1 mL of bacteriostatic water yields 10 IU/mL. A 2 IU dose draws to 0.20 mL (20 units on a 100-unit insulin syringe). 1 mg of somatropin ≈ 3 IU by WHO standard.
Per FDA labels: fluid retention/edema (especially in the first weeks), arthralgia, myalgia, carpal tunnel syndrome, paresthesia, insulin resistance (causing fasting glucose increases and sometimes overt T2DM), elevated triglycerides, and benign intracranial hypertension (rare). Long-term registry data (KIMS, HypoCCS) shows acceptable safety in adults treated for GHD at approved doses; safety at higher off-label doses is less well-characterized. Cancer recurrence/incidence concerns have been studied extensively without consistent signal in approved-indication use.
IGF-1 elevation is detectable within days. Subjective effects (sleep depth, recovery) often reported in the first 2–4 weeks. Body composition changes (lean mass increase, fat mass decrease) typically accumulate over 3–6 months of consistent daily dosing. Subcutaneous Tmax is 4–5 hours; terminal half-life is short (~2.5–2.8 hours) but the IGF-1 response sustains for 24+ hours, which is why daily dosing produces near-continuous IGF-1 elevation.
Yes. Somatropin and all recombinant growth hormones are prohibited at all times under WADA S2.2 (Growth Hormone and its analogues). The detection windows of modern GH isoform assays and the GH biomarker test catch use in many cases. No therapeutic-use exemption available for athletes outside genuine GHD diagnosis.
Disclaimer: This guide is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. The compounds discussed are not FDA approved for human use. Always consult a qualified healthcare provider before starting any new supplement or peptide protocol. StackTrax does not sell peptides or supplements directly — purchase links go to third-party vendors. StackTrax is not responsible for the products, quality, or business practices of any third-party vendor.
© 2026 StackTrax, LLC. All rights reserved.
Privacy · Terms · Do Not Sell or Share My Personal Information
StackTrax guides cover peptides and compounds that are not FDA-approved for the uses discussed. The dosing, reconstitution, and safety information is compiled from published research and community protocols for educational purposes only.
Before using any compound mentioned here, consult a qualified healthcare provider. StackTrax does not sell, prescribe, or recommend these substances for personal use.