HGH
Somatropin (recombinant human growth hormone) · Somatropin · rhGH · Human Growth Hormone · GH · Growth Hormone
Recombinant human growth hormone, the reference compound every GH peptide tries to imitate.
Typical dose
2 IU
Once daily, split into two injections above about 4 IU
Range
1–6
IU
Half-life
3 h
see Dosing
Evidence
Human trials
Subcutaneous · Intramuscular
What it is
HGH is a 191-amino-acid protein hormone made by recombinant DNA technology and structurally identical to the growth hormone the pituitary produces. Unlike secretagogues such as ipamorelin or MK-677, which ask your own pituitary to release more, injected GH bypasses the pituitary entirely, so the dose administered is the dose delivered.
Most of what people want from HGH happens downstream, through IGF-1 that the liver produces in response to it. That is why bloodwork for anyone running GH tracks IGF-1 rather than GH itself: endogenous GH is released in pulses, and a random serum GH reading tells you almost nothing.
Effects on body composition are real and well documented: lean mass up, fat mass down, visceral fat especially. Effects on strength and athletic performance are not. Systematic reviews of GH in healthy adults found body-composition change without matching gains in strength or exercise capacity, alongside clear increases in oedema, joint pain and impaired glucose tolerance. The connective-tissue and recovery benefits are what most experienced users actually value, and they arrive over months, not weeks.
How it works
Injected GH binds growth hormone receptors on liver, muscle, bone and fat cells. In the liver it drives IGF-1 production, which mediates most of the anabolic and tissue-repair effects. At the fat cell it is directly lipolytic and antagonises insulin, which is why fasting glucose and fasting insulin usually drift upward on it.
Exogenous GH also suppresses your own pulsatile release via negative feedback at the hypothalamus and pituitary. That is why adding a GHRH analogue or a ghrelin mimetic on top of pharmacological GH doses adds little, and why output stays blunted for weeks after a long run ends.
Dosing
Most of the lean-mass and fat-loss data in trials came from 1-2 IU per day. Above roughly 4 IU the rate of oedema, carpal tunnel and glucose problems climbs sharply for a modest extra return.
Standard titration
| Step | Dose | Note |
|---|---|---|
| Weeks 1-2 | 1 IU | Assess water retention and joint response before going higher |
| Weeks 3-4 | 2 IU | Where most long-term users settle |
| Week 5 onward | 3 IU | Only if side effects at 2 IU are minimal; split AM and PM above 4 IU |
Reconstitution calculator
Pre-loaded with HGH’s vial size, water volume and typical dose. Change anything.
Typical: 2 IU · range 1–6
Draw to
20 u
0.2 mL · 2 IU
Concentration
3.33 mg/mL
0.1 IU per unit
Doses per vial
5
Vial lasts
5 days
Draw to 20 units on the barrel.
Once mixed
2-8 degrees C and used within about 2-3 weeks. Do not freeze reconstituted GH, and discard it if the solution turns cloudy.
A 10 IU (3.33 mg) vial with 1 mL of bacteriostatic water gives 10 IU per mL, so 10 units on a U100 insulin syringe equals 1 IU. Aim the water down the inside wall of the vial rather than onto the powder, and swirl gently; shaking denatures the protein, and a cloudy or stringy solution means the vial is ruined.
Storage
Before mixing
Refrigerated at 2-8 degrees C. Generic kits are often shipped unrefrigerated and tolerate a few days at room temperature, but heat is what destroys GH, so anything that spent a week warm should be treated as suspect.
After mixing
2-8 degrees C and used within about 2-3 weeks. Do not freeze reconstituted GH, and discard it if the solution turns cloudy.
Reported benefits
- ▪Increases lean body mass and reduces fat mass, visceral fat in particular
- ▪Improves skin quality, sleep depth and general recovery for most users
- ▪Strengthens connective tissue over months, which is why it appeals to people with chronic tendon problems
- ▪Raises IGF-1 into a range that supports higher training volume
- ▪Well characterised across decades of human trials, unlike almost everything else in this database
- ▪Effective at low doses; 1-2 IU daily produced most of the documented body-composition change
Side effects
- ▪Water retention with puffy hands and face, worst in the first few weeks
- ▪Carpal tunnel syndrome and numb or tingling fingers, dose-dependent and usually reversible
- ▪Joint and muscle aches
- ▪Rising fasting glucose and falling insulin sensitivity; frank type 2 diabetes at high doses in susceptible people
- ▪Acromegalic changes on sustained high doses: thickened jaw and brow, widening hands and feet, coarsened features and spaced teeth. Soft-tissue change regresses on stopping, bone change does not
- ▪Intestinal and organ growth at sustained high doses, the source of the distended abdomen seen in some competitors
- ▪Can unmask or worsen hypothyroidism by shifting thyroid hormone conversion
- ▪Injection-site lipoatrophy if the same spot is used repeatedly
Do not use if
- ▪Active malignancy or recent cancer history; GH and IGF-1 are mitogenic
- ▪Active proliferative diabetic retinopathy
- ▪Poorly controlled type 2 diabetes or significant existing insulin resistance
- ▪Acute critical illness, where GH substantially increased mortality in ICU trials
- ▪Untreated sleep apnoea, which GH-driven soft-tissue growth tends to worsen
Evidence level — Human trials
Controlled human clinical data exists.
Prescription-only in most countries. In the United States somatropin is not a scheduled controlled substance, but 21 U.S.C. 333(e) makes distributing it, or possessing it with intent to distribute, for any use other than an FDA-approved indication on a physician's order a federal felony carrying up to five years. Prohibited in sport by WADA.
Commonly run with
IGF-1 LR3
Modified IGF-1 that evades its binding proteins, making it far more potent than the native hormone.
40 mcg · Once daily
BPC-157
Gastric-juice-derived pentadecapeptide studied for tendon, ligament and gut healing.
250 mcg · 1x daily (some split into 2x daily during an acute injury)
TB-500
Actin-regulating thymosin peptide used for soft-tissue repair and range of motion.
2.5 mg · 2x weekly during loading, then once every 1-2 weeks for maintenance
HGH FAQ
How much HGH do I actually need?+
1-2 IU per day is where the documented body-composition and recovery benefits sit, and it is what most trials used. Bodybuilding doses of 4-10 IU exist, but past roughly 4 IU the extra return is small next to the jump in water retention, carpal tunnel and glucose problems. Anyone running high doses should be checking IGF-1 and fasting glucose or HbA1c regularly.
Should I stack HGH with ipamorelin or CJC-1295?+
Not usefully at pharmacological doses. Injected GH suppresses your own pulsatile release through negative feedback, so a secretagogue asking a suppressed pituitary for more output has little to work with. Secretagogues are an alternative to GH, not an addition to it.
Morning or before bed?+
Either works. Morning fasted dosing lines up better with fat loss and leaves the natural night-time pulse intact; pre-bed suits people who find GH makes them drowsy. What matters more than the clock is keeping the injection away from a large carbohydrate meal.
How long before I see anything?+
Sleep and skin changes often show up within 2-4 weeks. Fat loss and lean-mass change take 3-6 months, and connective-tissue benefit is slower still. Anyone promising visible results in a few weeks at 2 IU is selling something.
IU or mg, which is right?+
They measure the same thing. 1 mg of somatropin equals 3 IU, so a 10 IU vial contains 3.33 mg. Pharmaceutical pens are usually labelled in mg and generic kits in IU, which is the only reason both units are in circulation.
References
- 1.Effects of human growth hormone in men over 60 years old — New England Journal of Medicine (1990) PMID 2355952
- 2.Systematic review: the safety and efficacy of growth hormone in the healthy elderly — Annals of Internal Medicine (2007) PMID 17227934
- 3.Increased mortality associated with growth hormone treatment in critically ill adults — New England Journal of Medicine (1999) PMID 10477776
- 4.Systematic review: the effects of growth hormone on athletic performance — Annals of Internal Medicine (2008) PMID 18347346