For most of its clinical life, human growth hormone meant a daily injection. Somatropin — recombinant hGH, 191 amino acids, identical to the pituitary hormone — was given nightly, often for years, to children with severe growth hormone deficiency. That is changing. Three once-weekly growth hormone analogues are now approved across major markets, two of them are already subsidised for Australian children, and daily somatropin is quietly becoming the comparator rather than the default.

The awkward part, and the reason this post exists: the weekly products have never been tested against each other. Every claim that one weekly hGH outgrows another comes from indirect statistics, not a randomised head-to-head. If you are researching human growth hormone in Australia and trying to work out what the evidence actually supports, that gap is the single most useful thing to understand.

What is long-acting growth hormone, and how is it different?

Daily somatropin is plain recombinant hGH. The weekly products are engineered to hang around longer:

  • Somatrogon (Ngenla) — hGH with three copies of the C-terminal peptide from the beta chain of hCG bolted on, which slows clearance. TGA-approved in Australia in November 2021.
  • Somapacitan (Sogroya) — hGH with a single amino acid substitution and an albumin-binding side chain, so it rides on circulating albumin.
  • Lonapegsomatropin (Skytrofa) — a prodrug that releases unmodified somatropin slowly from a carrier.

All three were approved for paediatric growth hormone deficiency on the back of phase 3 trials against daily somatropin — the shared control arm. None was trialled against another weekly. That design choice is entirely normal for regulatory purposes, but it means the clinical question families and endocrinologists actually ask ("which weekly?") has no direct answer.

The 2026 meta-analysis, and what it can and can't tell you

A network meta-analysis published in Endocrinology, Diabetes & Metabolism in 2026 (Abadi et al.) pooled 18 randomised controlled trials and 3,137 patients to try to rank the options statistically. Its reported findings: a weekly pegylated growth hormone (YPEG-rhGH, 0.1 mg/kg/week) showed significantly higher height velocity than daily somatropin, while somatrogon and somapacitan at 0.04 mg/kg/week did not come out ahead on that measure. It found no significant differences between treatments in progression of the bone-age-to-chronological-age ratio, or in serious adverse events.

Two caveats worth holding onto:

  1. Network meta-analysis is indirect. It compares A to C by way of their shared comparator B. That inference is only as good as the assumption that the trials were similar enough in age, severity, prior treatment and dose to be linked — an assumption that is rarely perfectly met in paediatric growth studies.
  2. Different analyses have reached different conclusions. An earlier systematic review and network meta-analysis in Advances in Therapy (2024) reported no differences at 52 weeks between somapacitan, somatrogon and lonapegsomatropin on growth outcomes, while a 2024 analysis in Scientific Reports ranked lonapegsomatropin first on annualised height velocity. Several of these analyses were produced with involvement from companies that market one of the products being ranked — always read the funding and conflict-of-interest statement before you read the conclusion.

The honest summary of the field in 2026: all three weeklies work, all three appear broadly comparable to daily somatropin over 52 weeks, injection-site pain has been reported more with somatrogon, and the differences between the weeklies are within the noise of indirect comparison. Long-term (final adult height, metabolic) data are still accumulating.

HGH in Australia: the PBS Growth Hormone Program is the real gatekeeper

Australia does not treat growth hormone as an ordinary prescription. It sits in its own Section 100 Growth Hormone Program under the National Health Act 1953, with its own eligibility criteria, its own application forms through Services Australia, and a requirement that treatment be under an endocrinologist. Authority approvals are granted by brand — the brand, form and strength must be specified on the prescription.

Where the weeklies sit:

  • Paediatric: the PBS subsidises somatropin, somatrogon and somapacitan for children with severe growth hormone deficiency. Ngenla was listed from 1 October 2022 as the first once-weekly growth hormone therapy funded for Australian children, at standard PBS co-payments rather than private cost.
  • Adult: the program subsidises somatropin for adults with severe childhood-onset or late-onset growth hormone deficiency, and for adults with Prader-Willi syndrome from age 18. Sogroya is TGA-registered for adult GHD in Australia; the adult side of the PBS program is the part to check against the current schedule rather than assume.

The Australian and New Zealand Society for Paediatric Endocrinology and Diabetes maintains a summary of growth hormone and IGF-1 PBS eligibility and prescribing rules, most recently updated in May 2026 — a useful indicator of how often the detail shifts.

Is HGH legal in Australia?

Growth hormone is Schedule 4 (prescription only) and border-controlled. Importing or possessing it without a valid Australian prescription is illegal, and it is on the WADA Prohibited List — the S2 peptide hormones class covers growth hormone and its analogues, in and out of competition. The weekly analogues change none of that; they are prescription medicines with a narrow set of approved indications, not a new consumer category.

It is also worth restating what the anti-ageing evidence shows, because the weeklies are sometimes marketed into that space by implication. Trials of growth hormone in healthy older adults have produced roughly 2 kg of lean mass — with oedema, joint pain and insulin resistance as recurring side effects, and no demonstrated benefit to function or longevity. None of the new formulations were studied for that purpose, and none is approved for it anywhere.

What to watch next

The trial that would settle the weekly-versus-weekly question — a properly powered, randomised, head-to-head study with final adult height as an endpoint — has no obvious commercial sponsor, because whoever funds it risks losing. Until one exists, treat any ranking of the weeklies as a statistical estimate with wide uncertainty, not a finding.

More background on the compound is in our HGH profile, and the full peptides library covers the wider space. For plain-English updates as the growth hormone evidence and PBS listings change, join the free list.

FAQ

Is weekly growth hormone better than daily somatropin?

Over 52 weeks, the approved weekly analogues have generally shown growth outcomes comparable to daily somatropin, with the main practical advantage being fewer injections. The 2026 network meta-analysis found one pegylated weekly product outperformed daily somatropin on height velocity, but not all weeklies did, and there are no head-to-head trials between the weeklies.

Is long-acting growth hormone available on the PBS in Australia?

Yes, for defined indications. The PBS Section 100 Growth Hormone Program subsidises somatropin, somatrogon and somapacitan for paediatric patients with severe growth hormone deficiency; Ngenla (somatrogon) was listed from 1 October 2022. Prescribing runs through an endocrinologist and is approved by brand.

Is HGH legal in Australia?

Growth hormone is a Schedule 4 prescription-only medicine and is border-controlled, so importing or possessing it without a valid prescription is illegal. It is also prohibited in sport at all times under the WADA Prohibited List.

Does HGH work for anti-ageing?

Trials in healthy older adults have shown only around 2 kg of lean mass gain, accompanied by oedema, joint pain and insulin resistance, with no demonstrated improvement in function or lifespan. No growth hormone product — daily or weekly — is approved for anti-ageing use in Australia.

Sources

This article is independent information, not medical advice. Somatropin and its long-acting analogues are TGA-approved, Schedule 4 prescription-only medicines subsidised for defined conditions through the PBS Growth Hormone Program; retatrutide.net.au is not affiliated with any manufacturer and does not sell or source any compound.