Somatropin (recombinant human growth hormone, hGH)
HGH: What The Studies Actually Say
A real prescription drug for a short list of growth problems and a proven lack of growth hormone. In healthy people, trials found more lean mass, no clear gain in strength, and more side effects. It has never been approved for anti-aging.
Updated 22 September 2026
Before you read this
This page explains what published studies found. That is all it is. It is not medical advice, and it is not instructions for using anything. Nothing here is meant to find, treat, cure or stop any illness. The compounds discussed on this site, retatrutide included, are not approved by the FDA for use in people. Research compounds are sold for laboratory use only — not for use in humans or animals. A study tells you what happened to the people in it. It does not tell you what would happen to you. What you do with what you read here is your responsibility, so talk to a doctor first. This page is published by Ascend Vials, which sells research compounds.
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HGH is a real medicine. In the US it is a prescription drug for a short list of uses, most of them in children who are not growing normally.
Most of what you hear about it is something else: staying young, getting stronger. Those claims were tested in real trials. Here is what they found. Every claim has a link. Read them yourself.
The 30-second version
- HGH (somatropin) is an FDA-approved prescription drug for a short list of uses: mostly children who are not growing normally and adults with a proven lack of growth hormone.
- In healthy older adults it added about 2 kg of lean mass and took off 2 kg of fat. Weight did not change, and strength did not clearly improve.
- In fit young adults: more lean mass, but no clear gain in strength or exercise capacity.
- Side effects were common: swelling, joint pain and carpal tunnel. Diabetes and blood-sugar trouble turned up more often too.
- In very sick patients in intensive care, high doses roughly doubled the death rate.
- It is not approved for anti-aging. In the US, distributing it for that is illegal. It is banned in sport at all times.
- Nothing sold online has been tested against what these studies used. None of these studies checked.
The numbers, from the real studies
The big claim is that HGH turns back the clock. A 2007 review pulled together the randomized trials in healthy older people: 18 study groups, 220 people on GH, average age 69, about 27 weeks of treatment. Annals of Internal Medicine, 2007
Fat went down. Lean mass went up. Weight did not move. Bone density and most blood fats did not change. Annals of Internal Medicine, 2007
People on GH got more swelling, joint pain, carpal tunnel syndrome (a pinched nerve in the wrist) and breast growth in men. They were somewhat more likely to develop diabetes or high blood sugar. Most of the studies were small. The authors' conclusion: GH cannot be recommended as an anti-aging therapy. Annals of Internal Medicine, 2007
More lean mass is not more strength
"Lean mass" sounds like muscle. It is really everything in the body that is not fat, water included.
In 52 healthy men over 69, six months of GH raised lean mass 4.3% and cut fat 13.1%. Men on a fake shot barely changed. But knee strength, grip strength and endurance came out the same in both groups. The men on GH had 48 side-effect incidents, against 14 on the fake shot, and about 1 in 4 needed their dose cut. Annals of Internal Medicine, 1996
In 131 women and men aged 65 to 88, strength did not clearly go up after 26 weeks either. The one borderline exception was men given GH plus testosterone. JAMA, 2002
You may also see a 1990 study quoted as proof that HGH reverses 10 to 20 years of aging. The paper does not say that. It gave GH to just 12 older men, and its summary does not say they were assigned at random. New England Journal of Medicine, 1990 The bigger trials after it found small body changes, little or no gain in strength, and frequent side effects. Annals, 1996 · JAMA, 2002
In athletes: more mass, no clear edge
A 2008 review pooled the randomized trials in fit young people: 303 on GH, average age 27, about 20 days of treatment. Lean mass rose 2.1 kg, but strength and exercise capacity did not appear to improve. People on GH had more swelling and tiredness. The authors said GH may even make exercise capacity worse. Annals of Internal Medicine, 2008
A trial paid for by WADA, the anti-doping agency, gave 96 recreational athletes GH or a fake shot for 8 weeks. The extra lean mass came through extra water outside the cells. Sprint capacity rose 3.9%, but endurance, strength and jump height did not clearly change. Six weeks after stopping, the sprint gain had not lasted. Annals of Internal Medicine, 2010
What about living longer?
No randomized trial has shown that GH makes healthy older people live longer. Annals of Internal Medicine, 2007
In mice it points the other way. Mice that cannot respond to GH lived longer than normal mice. Endocrinology, 2000 Mice bred to make too much GH had drastically shorter lives. Neuroendocrinology, 2003 Those are mice, not people.
In Ecuador, 99 people with a gene change that stops them responding to GH had one non-fatal cancer and no diabetes over 22 years. Among their relatives, 17% had cancer. But they did not live longer, and this compares families. It says nothing directly about taking GH. Science Translational Medicine, 2011
What it has been tested for
Here is what has actually been tested in people, and where the drug is approved.
| Biggest evidence in people | What it found | Approved for it? | |
|---|---|---|---|
| Turner syndrome (girls) | 1 trial, 154 girls, to adult height | About 7 cm taller at the end | Yes, US and EU |
| Prader-Willi syndrome (children) | 2 small trials, 43 children | 11.6 cm of growth in a year, against 5.0 cm untreated | Yes, US and EU |
| Born small, no catch-up growth | 4 trials, 209 children, 2 years | Height score up 1.2 to 1.7, against 0.1 untreated | Yes, US and EU |
| Short for no known reason | 3 trials, 115 children, to adult height | About 4 cm taller as adults, on average | Yes, US |
| Adults with a proven lack of GH | 37 blinded trials, pooled | Lean mass +2.7 kg, fat −3.1 kg, LDL down, fasting blood sugar up | Yes, US and EU |
| Wasting in adults with HIV | 1 trial, 757 people, 12 weeks | About 9% more work on an exercise bike | Yes, US |
| Healthy older adults (anti-aging) | 18 study groups, 220 on GH, about 6 months | Lean mass +2.1 kg, fat −2.1 kg, weight unchanged | No |
| Fit young adults (sport) | 27 study groups, 303 on GH, about 20 days | Lean mass +2.1 kg, no clear gain in strength | No, banned in sport |
| Very sick adults in intensive care | 2 trials, 532 people | Death rate roughly doubled | No, the label rules it out |
A height score compares a child with others of the same age. Zero is average.
Read the whole table. The two rows about healthy people — anti-aging and sport — are both "no." Every "yes" is for a specific medical condition.
Even the "yes" rows have limits. In children who are short for no known reason, the response varied widely, and the average gain was smaller than in the other approved conditions. BMJ, 2011 Whether that extra height improves their wellbeing is still undetermined. Source
Sources: Turner, JCEM 2005 · Prader-Willi and born small: FDA label · short stature, BMJ 2011 · short stature trial, JCEM 2004 · adults lacking GH, JCEM 2004 · HIV: Serostim label · older adults, Annals 2007 · athletes, Annals 2008 · intensive care, NEJM 1999
What it is
HGH stands for human growth hormone. The drug is called somatropin. It is a lab-made copy of the hormone the pituitary gland makes, built in E. coli bacteria. It is 191 building blocks long, in exactly the same order as the natural one, and it is given as an injection under the skin. FDA label
It locks onto growth hormone receptors on cells and switches on other proteins, including IGF-1, a hormone the body makes when growth hormone goes up. FDA label, Norditropin The label says it makes long bones grow at their growth plates, builds muscle cells, pulls fat out of fat stores, and makes the body hold on to protein and minerals. At large doses it may make blood sugar harder to control. FDA label
This page does not cover the long-acting versions, or the "fragments" known as AOD-9604 and hGH 176-191. The anti-doping list names those separately. WADA, 2026
What to expect
These are the side effects from the FDA label's trials in adults who truly lacked growth hormone: 1,145 people, first six months, GH against a fake shot. FDA label
| Placebo | HGH | |
|---|---|---|
| Swelling in arms or legs | 5.1% | 17.5% |
| Joint pain | 4.2% | 17.3% |
| Pain in arms or legs | 5.9% | 14.7% |
| Fluid build-up (edema) in arms or legs | 2.6% | 10.8% |
| Tingling | 1.9% | 9.6% |
The label says this fluid build-up usually passes and depends on the dose. FDA label It ran higher in healthy older adults: swelling in 39% of women on GH and joint pain in 41% of men on GH, against 0% without it. JAMA, 2002
Two bigger things:
Blood sugar. The label warns that GH can make the body less sensitive to insulin. FDA label In the older-adult trial, 18 men on GH developed diabetes or glucose intolerance, against 7 not on it. JAMA, 2002 Among 23,333 children given GH, type 2 diabetes turned up six times more often than reported in children not on it, and it did not go away when GH stopped. Lancet, 2000
Very sick patients. In two trials of 532 adults in intensive care, high doses roughly doubled the death rate in hospital: 39% against 20% on placebo in one, 44% against 18% in the other. New England Journal of Medicine, 1999 The current label rules it out in these same situations. FDA label
The label also rules it out for anyone with active cancer. It reports a higher risk of a second tumor in childhood cancer survivors who had radiation to the head, and deaths in children with Prader-Willi syndrome who were severely obese or had breathing problems. It also warns of pressure building inside the skull, a slipped hip growth plate in children, worse scoliosis, pancreatitis and serious allergic reactions. FDA label For adults who truly lack growth hormone, the Endocrine Society calls the risks of treatment low, and says the decision needs careful judgment for each patient. Endocrine Society, 2011
Children followed for decades
Children given GH in the 1980s and 1990s have now been followed into adulthood. These studies show links, not proof, and they do not all agree.
- France, 6,928 people: deaths from any cause were 1.33 times the general population, and higher still on the highest doses. Overall cancer deaths were not raised. JCEM, 2012
- France, 6,874 people: bleeding strokes were 3.5 to 7 times more common than in stroke registries. The authors called for studies of whether GH is the cause. Neurology, 2014
- 8 countries, 24,232 people: in the lowest-risk patients, deaths were not clearly raised. Deaths from heart, blood-vessel and blood diseases were raised in every group. Lancet Diabetes & Endocrinology, 2020
- Cancer, 23,984 people: the extra cancer was mostly second cancers in people who had cancer before. In everyone else, only bone and bladder cancer were clearly raised. The authors said the results do not generally point to GH causing cancer. JCEM, 2017
The old version came from human glands
Before 1985, growth hormone was taken from the pituitary glands of people who had died. The US stopped giving it out in 1985 after cases of Creutzfeldt-Jakob disease (CJD), a brain disease. Among nearly 7,700 US patients, 36 cases have been found, 14 to 51 years after treatment began. NIDDK · Nature Medicine, 2024
In the UK, at least 1,848 people got the old hormone. Doctors at a specialist clinic have described 8 of them. Five had symptoms of early-onset dementia, starting at ages 38 to 55. The doctors place it within Alzheimer's disease, and propose that the old batches carried amyloid-beta "seeds" that passed it on. Nature Medicine, 2024
Today's lab-made HGH is a different product. NIDDK says it poses no threat of CJD. NIDDK The dementia paper covers only the old hormone. Full paper
Approved, for narrow uses
- United States: approved as a prescription drug. The current labels for Genotropin, Humatrope, Norditropin and Serostim all list first US approval as 1987. The uses differ by brand: growth problems in children from a lack of growth hormone and from conditions such as Turner syndrome, Prader-Willi syndrome and Noonan syndrome; a proven lack of growth hormone in adults; and, for Serostim only, wasting in adults with HIV. Genotropin · Humatrope · Norditropin · Serostim
- US law: knowingly distributing HGH for any human use other than treating a disease or recognized medical condition, authorized by the health department and ordered by a doctor, is a federal crime. The penalty is up to 5 years in prison, or 10 if someone under 18 is involved. 21 U.S.C. 333(e) It is not approved for anti-aging, and distributing it for that is illegal. Annals of Internal Medicine, 2007
- Europe: approved. For example, Omnitrope, a close copy of Genotropin, has been authorised EU-wide since 2006, for several growth conditions in children and a severe lack of growth hormone in adults. EMA
- Sport: banned at all times on the 2026 anti-doping list, along with its long-acting versions and fragments. WADA, 2026
- Other countries were not checked for this page.
None of the approvals we checked cover anti-aging, bodybuilding, fat loss or sports performance.
What is still unknown
Decades of use have not closed these questions:
- Heart attacks, strokes and deaths in adults who truly lack GH. Risk markers like cholesterol improve, insulin sensitivity gets worse, and large trials are still needed. JCEM, 2004
- The stroke and death signals in people given GH as children. Nobody knows yet whether they come from GH or from the conditions being treated. Lancet Diabetes & Endocrinology, 2020
- The bone, bladder and Hodgkin lymphoma signals. They need more study. JCEM, 2017
- Anything anti-aging. There is no randomized evidence that it extends life or improves strength or function in healthy older people. Annals of Internal Medicine, 2007
- What athletes actually use. The doses and mixes taken in secret are untested, and the WADA trial was too small to judge safety. Annals of Internal Medicine, 2010
What is in the bottle is not what was studied
One more thing.
Every result on this page came from pharmaceutical growth hormone, given in a study or under a doctor's care.
None of these studies tested a product sold online as "HGH" or "research HGH." So nothing here shows those products are the same thing. Not the same purity. Not the same strength. Not proof they are sterile. Not even proof they are the same molecule.
The real drug does exist: in the US it is a prescription medicine, for the uses listed above.
So take every number on this page for what it is. It describes pharmaceutical somatropin, in the people who were studied. It describes nothing else.
How to check a number yourself
You are going to see more numbers about HGH. In a reel. In a comment. On somebody's store page.
Here is how to tell a real one from a marketing one. Five questions. About ten seconds each.
1. Is there a link to a study?
A real number comes from a paper you can open. No link means it is a claim, not a result. Search the drug name on pubmed.gov yourself. With HGH you will find a lot of real trials — so the next four questions matter even more.
2. How big was it, and how long did it run?
Small studies swing. The 1990 study gave GH to 12 men. The athlete trials lasted about 20 days on average. A number is only true for the size and length of the study behind it.
3. Was there a group that got nothing?
The fake shot is the whole point. In the 1996 trial, fat and lean mass changed on GH — but strength came out the same in both groups. Without that group, nobody can tell how much of a change was the drug.
4. Did it measure what you care about?
Most HGH headlines are about lean mass. Lean mass is not strength, and it is not all muscle. Look for the line about strength or endurance. On this page, it mostly says "no clear change."
5. Who was in it?
A number is only true for the people who were studied. The growth numbers come from children with specific conditions. The adult replacement numbers come from adults who truly lack growth hormone. In very sick patients, the same drug roughly doubled the death rate. None of those groups is a healthy adult trying to stay young.
Now run those five on this page
Every number above links to the paper it came from. The study sizes and who was in them are in the table. The fake-shot comparisons are in the side-effect table. Lean mass versus strength has its own section. And the long-term studies are labelled as links, not proof.
The claims made for HGH outside its approved uses — younger, stronger, faster — are the ones the trials did not back up.
That is the whole difference: a number you can check, and a number you are asked to believe.
This page has a date on it, near the top. When new studies publish, this page changes.
Read the studies yourself
- Anti-aging review, Annals of Internal Medicine 2007 — the main one
- Older men, Annals 1996 · older women and men, JAMA 2002 · the 1990 study, NEJM
- Athletes review, Annals 2008 · WADA-funded trial, Annals 2010
- FDA label, Genotropin — side effects and warnings · Norditropin · Humatrope · Serostim
- Intensive care trials, NEJM 1999
- Adults lacking GH, JCEM 2004 · Endocrine Society guideline, 2011
- Turner syndrome, JCEM 2005 · short stature trial, JCEM 2004 · its wellbeing report · short stature review, BMJ 2011
- French deaths, JCEM 2012 · stroke, Neurology 2014 · 8-country deaths, Lancet Diabetes & Endocrinology 2020 · cancer, JCEM 2017 · diabetes in children, Lancet 2000
- Old pituitary hormone, NIDDK · dementia report, Nature Medicine 2024 · free full text
- Ecuador study, Science Translational Medicine 2011 · mice, Endocrinology 2000 · mice, Neuroendocrinology 2003
- US law, 21 U.S.C. 333 · EMA, Omnitrope · WADA 2026 Prohibited List
Everything above describes what studies gave to patients and volunteers under a doctor's care. This is not advice, a plan, or instructions. In the US, somatropin is a prescription medicine for specific approved uses, and distributing it for other uses is a crime. Research compounds are not for human or animal use.