Growth hormone is one of the few peptides on this site with a genuine, decades-long paediatric evidence base — and also one where the strongest single question is still answered by a surprisingly small dataset. If you want to know what HGH is used for beyond the anti-ageing marketing, the most instructive case is idiopathic short stature (ISS): healthy short children with no hormone deficiency, no syndrome, and no disease. In February 2026 the US FDA added ISS to the label of a once-weekly growth hormone. The randomised, placebo-controlled trial that established growth hormone increases adult height in ISS reported adult height in 33 children. That gap between the size of the market and the size of the evidence is today's story.

For background on the molecule itself, see our HGH profile.

What is idiopathic short stature, and why is it different?

ISS is a diagnosis of exclusion: height more than about two standard deviations below the mean for age and sex, with normal growth hormone secretion, no chronic illness, no Turner syndrome, no skeletal dysplasia, and no small-for-gestational-age history. These children are not hormone-deficient. Treating them with somatropin is not replacement therapy — it is pharmacology aimed at a statistical position on a growth chart.

That distinction matters for how evidence should be judged. In severe growth hormone deficiency, the counterfactual is obvious and untreated outcomes are poor. In ISS, the untreated child still grows, still finishes puberty, and still reaches an adult height — just a shorter one. So the only endpoint that answers the question is final adult height versus placebo, and that requires following children for years.

The 33 adult heights

Only one randomised, double-blind, placebo-controlled trial has done that properly. Leschek and colleagues (JCEM, 2004) enrolled 68 peripubertal children aged 9–16 with marked ISS, randomised them to growth hormone or placebo, and treated for a mean of 4.4 years. Adult height was available for 33 participants at study termination. The treated group ended up taller by 0.51 height standard deviation scores — about 3.7 cm (P < 0.02).

Three things follow, and all three are usually left out of promotional summaries:

  • 3.7 cm is the honest number, not the 8–10 cm/year growth velocity figures quoted from first-year data. Short-term height velocity in a growing child is a surrogate; some of it is simply growth brought forward, and bone age advances with it.
  • n = 33 for the primary long-term outcome is small for a treatment given daily for years to otherwise healthy children. It has not been replicated in a comparable placebo-controlled adult-height design.
  • The trial measured centimetres, not wellbeing. It did not establish that the added height changes quality of life, employment, or psychological outcomes. Whether it does remains genuinely contested, and the studies that try to address it are small, short, and largely open-label.

What the 2026 approval actually tested

Novo Nordisk announced on 27 February 2026 that the FDA had approved once-weekly somapacitan (Sogroya) for children aged 2.5 years and over with ISS, with short stature born small for gestational age without catch-up by age two, and for growth failure in Noonan syndrome. The supporting REAL8 trial was an open-label, randomised, phase 3 basket study whose endpoint was annualised height velocity at week 52 — in the ISS group, 10.2 cm/year on weekly somapacitan versus 10.5 cm/year on daily somatropin, interpreted as non-inferior.

Read that carefully. REAL8 asked whether a weekly injection matches a daily one over a year. It did not re-ask whether treating ISS improves adult height, and it was not designed to. The label expansion is a convenience and formulation story layered on top of an efficacy question that still rests largely on the 2004 dataset. This is a company announcement and regulatory action, not new long-term outcome evidence.

HGH Australia: how our system routes the same children

Here is the local angle, and it's a real one. Australia does not have a PBS category called "idiopathic short stature." Instead, the PBS Growth Hormone Program includes an auxology-based category — short stature and slow growth — that catches many of the same children without ever labelling them deficient.

According to the ANZSPED summary of PBS eligibility and prescribing criteria (updated 2026), that pathway broadly requires current height at or below the 1st percentile for age and sex plus growth velocity below the 25th percentile for bone age measured over 12 months (or six months in an older child), with mature-height ceilings and exclusions for constitutional delay where predicted adult height is already adequate. In other words: Australia gates access on measured growth failure rather than on a diagnostic label, and the numeric thresholds are stricter than the "two standard deviations below the mean" definition used in the ISS literature. Prescribers should always work from the current PBS schedule and Services Australia criteria rather than any summary, including this one.

On the formulation side, somapacitan is TGA-registered in Australia (as Sogroya) for replacement of endogenous growth hormone in adults with growth hormone deficiency — the paediatric ISS indication approved in the US is not part of the Australian registration. European regulators issued a positive opinion on an ISS extension in 2026; Australia is a separate process with its own timing.

Is HGH legal in Australia?

Somatropin is a Schedule 4 (prescription-only) medicine and is border-controlled. It is TGA-approved and PBS-subsidised only for defined conditions, assessed against published criteria. Possessing or importing it without a prescription is illegal, and it is prohibited at all times in sport under the WADA code. This site does not discuss sourcing, and there is no legitimate consumer channel for it in Australia.

The adult "anti-ageing" contrast

The paediatric literature is often borrowed to imply adult benefit. It doesn't transfer. In healthy older adults, trials of growth hormone have produced roughly 2 kg of lean mass with no demonstrated gain in strength, function or longevity — alongside oedema, joint pain, carpal tunnel symptoms and worsened insulin sensitivity. That risk–benefit profile is a big part of why the approved indications are narrow and why the ISS debate is fought over a few centimetres rather than dismissed as trivial.

Browse the rest of our peptide profiles for comparable evidence breakdowns, and join the free updates list if you want new HGH research and TGA developments as they land.

FAQ

What is HGH used for in children?

TGA-approved and PBS-subsidised uses are narrow and defined — including severe growth hormone deficiency and other specified growth disorders — with eligibility assessed against published auxological criteria rather than a general "short stature" request.

How many centimetres does growth hormone add in idiopathic short stature?

The one randomised placebo-controlled trial with adult-height data found about 3.7 cm (0.51 SDS) more than placebo, based on adult heights in 33 children after a mean 4.4 years of treatment.

Is HGH legal in Australia?

Somatropin is Schedule 4 prescription-only and border-controlled. Non-prescribed possession or importation is illegal, and it is banned at all times in sport under WADA rules.

Is weekly growth hormone approved for short stature in Australia?

Not for paediatric idiopathic short stature. Somapacitan is TGA-registered for adult growth hormone deficiency; the ISS indication was approved in the US in February 2026 and is a separate regulatory question here.

Sources

Not medical advice. Somatropin is a TGA-approved, PBS-subsidised Schedule 4 prescription medicine for defined conditions only; it is border-controlled and WADA-prohibited. retatrutide.net.au is independent and not affiliated with any manufacturer, clinic or supplier.