Somapacitan (Sogroya)_Dosage, benefits & legal status
Also known as Sogroya, somapacitan-beco, NN8640
Weekly because albumin holds onto it, not because it lasts a week.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Somapacitan (Sogroya)?
Plain language first. The technical label stays, but it never stands alone.Overview
This is lab-made growth hormone with a chemical handle attached so it sticks to a blood protein and hangs around long enough for weekly injections. It matters for two reasons. It is the only once-weekly growth hormone approved for children who are short without being growth hormone deficient, covering three separate conditions added in February 2026. It is also the clearest example of a trick worth understanding: the weekly schedule comes from the side chain parking the drug on albumin, not from the drug itself lasting a week. Its half-life is 2 to 3 days in adults and only about 34 to 37 hours in children.
Somapacitan is a growth hormone analog. The label describes a single substitution in the 191 amino acid backbone, L101C, with an albumin-binding side chain made of an albumin binder and a hydrophilic spacer attached at position 101. Total molecular weight is 23,305.10 g/mol, of which the albumin-binding moiety accounts for 1,191.39. Binding to albumin is reversible and non-covalent, so the molecule circulates as a complex and dissociates to act, and nothing converts it back into unmodified somatropin. It is approved for pediatric patients aged 2.5 years and older with growth hormone deficiency, short stature born small for gestational age, Noonan syndrome or idiopathic short stature, and for growth hormone replacement in adults.
What it's used for
Growth failure from growth hormone deficiency, short stature in children born small for gestational age with no catch-up growth by age 2, growth failure with Noonan syndrome, and idiopathic short stature, all in children aged 2.5 and older. Also growth hormone replacement in adults with a deficiency.
How does Somapacitan (Sogroya) work?
What it does in the body, and where.Three approved products reach once-weekly growth hormone three different ways. This one modifies the hormone permanently and leans on a blood protein to make it last.
- 01One residue changed, one handle addedHuman growth hormone is 191 amino acids. The label describes a single backbone substitution, L101C, meaning the leucine at position 101 becomes a cysteine. That new cysteine is the anchor point: an albumin-binding side chain, made of a fatty albumin binder plus a hydrophilic spacer, is attached there. Of the molecule's 23,305 daltons, about 1,191 is that side chain.
- 02Albumin as a parking lotAlbumin is the most abundant protein in blood. The side chain binds it reversibly, so most of an injected dose is held on albumin rather than circulating free, and only the unbound fraction reaches growth hormone receptors at any moment. Binding and release continue throughout the week, and that is what flattens the profile enough for weekly dosing.
- 03What it never doesThe side chain does not come off. Unlike the prodrug approach used by lonapegsomatropin, nothing in the body converts somapacitan into ordinary somatropin. Whatever binds the receptor is always the modified molecule. That is the central difference between these two products and it is worth holding onto, because it is why their doses are not comparable.
- 04The half-life surpriseA weekly injection suggests a drug that lasts a week. The label says otherwise: approximately 2 to 3 days in adults with growth hormone deficiency, and about 34 hours in children at the 0.16 mg/kg dose or 36 to 37 hours at 0.24 mg/kg. Those are not contradictory figures, they are different populations. Weekly dosing works because the albumin reservoir keeps enough drug available between injections, not because a dose survives for seven days.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
What changed in 2026
FDA-approved- RegulatoryThree efficacy supplements were approved together in February 2026, adding short stature born small for gestational age, Noonan syndrome and idiopathic short stature. The pediatric age floor on the current label is 2.5 years.
- RegulatoryThis makes it the only long-acting growth hormone approved for short stature in children who are not growth hormone deficient.
- No dataTurner syndrome was studied in the same program but is not a United States indication.
The half-life does not match the schedule
FDA-approved- RegulatoryApproximately 2 to 3 days in adults with growth hormone deficiency, per the label.
- RegulatoryAbout 34 hours in children at 0.16 mg/kg, and 36 to 37 hours in children at 0.24 mg/kg. These are different populations rather than conflicting measurements.
- No dataNo long-acting growth hormone product on this site has a one-week half-life. Weekly dosing is a schedule, not a duration.
Not a gray-market compound, and there is a reason
none- No dataWe found no research-peptide vendor offering somapacitan. It requires chemical conjugation of a side chain onto a 191-residue protein, so there is no solid-phase synthesis route of the kind that supplies short research peptides.
- RegulatoryNamed by name on the WADA 2026 Prohibited List among the growth hormone analogs. The United Kingdom's medicines regulator reported no post-marketing misuse reports for this product.
The first error is lumping this in with HGH. Ordinary somatropin is the unmodified 191-residue hormone injected daily with a half-life of hours; this is a permanently modified molecule with a fatty side chain, dosed weekly, and it never reverts to plain somatropin. The second is assuming a weekly injection means a week-long drug. The label says 2 to 3 days in adults and about 34 to 37 hours in children. The third, and the one most likely to mislead in practice, is comparing doses across the three long-acting growth hormones. The 0.16 and 0.24 mg/kg figures here count the whole somapacitan molecule including its side chain, Skytrofa's 0.24 counts only its somatropin portion and excludes the carrier, and Ngenla's 0.66 counts an entire fusion protein. Three numbers, three different things being weighed. Last, the two doses on this label are not a range to pick from: 0.16 is for growth hormone deficiency and 0.24 is for the short-stature indications.
The published record
Papers and trials about Somapacitan (Sogroya)
Searched: somapacitan, Sogroya, REAL 8.
Left out: growth hormone (tens of thousands of records spanning decades; the most important rejection on all three growth hormone rows); somatropin (the unmodified hormone, which has its own slug as HGH); long-acting growth hormone (a class term matching lonapegsomatropin and somatrogon, each with its own slug); REAL 9 (a different study: 47 participants, single-arm, no comparator, adverse-event primary outcomes. Easy to mistake for REAL 8 and it would misattribute results); short stature (a clinical descriptor with a very large pediatric endocrinology literature).
86 papers tagged human · 43 not reviews or lab · 27 clinical trial publications
21 registered trials · 8 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Somapacitan (Sogroya)
Evidence
FDA-approved
Category
Growth hormone
Common vial
Varies
Half-life
2 to 3 days in adults, about 34 to 37 hours in children
How much, and do you cycle it?
The range, and whether you take breaks.0.16 to 0.24 mg/kg weekly, once weekly. Continuous weekly dosing while growth plates are open, or indefinitely in adults FDA label
Growth hormone replacement is continuous treatment. In children it continues while the growth plates remain open; in adults it is ongoing replacement. No cycling scheme applies.
How long does it stay in the body?
The half-life, and where the figure comes from.2 to 3 days in adults, about 34 to 37 hours in childrenFDA label
The label gives two separate figures for two populations, not one disputed figure. Adults with growth hormone deficiency: approximately 2 to 3 days. Children: about 34 hours at the 0.16 mg/kg dose and 36 to 37 hours at 0.24 mg/kg. Neither is close to a week, and weekly dosing rests on the albumin reservoir rather than on the molecule surviving seven days.
Source: Sogroya prescribing information, section 12.3
You can compare this against the whole library to see where it sits.
How is it given?
Dosing context and source notes.Supplied as a pen or prefilled syringe, so there is nothing to mix.
Label range: 0.16 up to 0.24 mg/kg per week.
The label gives 0.16 mg/kg once weekly for growth hormone deficiency and 0.24 mg/kg once weekly for short stature born small for gestational age, Noonan syndrome and idiopathic short stature, both on actual body weight. A missed dose may be given within 3 days. These figures count the mass of the somapacitan molecule including its side chain, so they cannot be set beside the other long-acting growth hormones' numbers. Recorded as a prescribing fact, not as guidance.
How do you store it?
Before mixing, and after.Follow the storage on the product label.
Somapacitan (Sogroya) is supplied as a finished product, so its label sets the storage. Pens, prefilled syringes, implants, tablets and ready-made solutions are used as supplied. Kits that include a powder are mixed just before the dose and usually used straight away, not kept for weeks. Many injectable products go in the fridge and must not be frozen, while others are kept at room temperature, so check the pack or ask the pharmacist.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Any use outside a prescription: this is a prescription biologic, not a research peptide, and we found no vendor offering it
- Comparing its mg/kg dose against the other long-acting growth hormones, since each counts a different molecular mass
Stop and get help
- Signs of raised pressure inside the skull, such as persistent headache with vision changes or vomiting
- Signs of an allergic reaction to the injection
Common effects
- Injection-site reactions, headache and joint pain, as with growth hormone treatment generally
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Somapacitan (Sogroya) approved?
And where the numbers on this page come from.Yes. Somapacitan (Sogroya) is FDA approved and available on prescription in the United States. It is also approved in the European Union and Japan.
- Approval statusFDA-approved
- RouteUnder the skin (weekly injection)
- Checked30 October 2026
- Approved outside the USEuropean Union, Japan.This does not change the United States position above.
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
What has happened recently
FDA-approved under BLA 761156, originally in August 2020 for adult growth hormone deficiency, with pediatric growth hormone deficiency added in 2023. In February 2026 three efficacy supplements were approved together, adding short stature born small for gestational age, Noonan syndrome and idiopathic short stature, and the current label sets the pediatric floor at 2.5 years. That February 2026 expansion is the newest regulatory development among the three long-acting growth hormones on this site and the reason this one leads. Note that Turner syndrome was studied in the same trial program but is not a United States indication. The 2026 WADA Prohibited List names somapacitan by name in section S2.2.3 as a growth hormone analog, in the same clause as lonapegsomatropin and somatrogon. The United Kingdom's Advisory Council on the Misuse of Drugs assessed all three in 2025 and recommended control, and the medicines regulator reported no post-marketing misuse reports for this product.
Banned in drug-tested sport. Most research peptides are prohibited under WADA's S0 category, which covers any substance with no approval from any regulatory authority for human use. That means a compound can be banned without ever being named on the prohibited list. Check with your own anti-doping authority rather than assuming absence from the list means permitted.
You can compare this against the whole library, or read how to check a seller.
What else is like Somapacitan (Sogroya)?
Others in Growth hormone peptides, side by side.If you're weighing Somapacitan (Sogroya), it's worth reading Somatostatin, Somatrogon (Ngenla), and Tesamorelin in the same class.
Weekly because albumin holds onto it, not because it lasts a week.
- Dose
- 0.16 to 0.24 mg/kg weekly
- How often
- Once weekly
A hormone that works, with a half-life too short to be practical.
- Dose
- 3.5 mcg/kg/hour
- How often
- Continuous infusion, 48 to 120 hours
Weekly because it is wrapped in carbohydrate, not because it is modified cleverly.
- Dose
- 0.66 mg/kg weekly
- How often
- Once weekly
An approved shot proven to shrink stubborn belly fat.
- Dose
- 1.28 up to 2 mg per day, depending on which product you have
- How often
- Daily
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
Sources
- Sogroya (somapacitan-beco) prescribing information(2026)The label, read through the FDA's own label API. Describes a human growth hormone analog with a single substitution in the amino acid backbone, L101C, an albumin-binding side chain consisting of an albumin binder and a hydrophilic spacer, attached to position 101 of the protein, a protein part of 191 amino acids, and a molecular weight of 23,305.10 g/mol of which the albumin-binding moiety is 1,191.39. Indications: pediatric patients aged 2.5 years and older with growth hormone deficiency, short stature born small for gestational age with no catch-up growth by 2 years of age, growth failure associated with Noonan syndrome, and idiopathic short stature; plus replacement of endogenous growth hormone in adults with growth hormone deficiency. Dosage 0.16 mg/kg once weekly for deficiency and 0.24 mg/kg once weekly for the other three. Half-life approximately 2 to 3 days in adults with growth hormone deficiency, about 34 hours in pediatric deficiency at 0.16 mg/kg, and 36 to 37 hours in pediatric small-for-gestational-age, Noonan and idiopathic short stature at 0.24 mg/kg. No boxed warning appears.
- WADA 2026 Prohibited List, section S2.2.3(2026)Read in an official government reproduction of the list. Section S2.2.3 is the clause covering growth hormone together with its analogs and fragments. It names lonapegsomatropin, somapacitan and somatrogon among the analogs, and AOD-9604 and hGH 176-191 among the fragments. Section S2.2.4 separately names tesamorelin, sermorelin, CJC-1295, ipamorelin and ibutamoren, also called MK-677. All five of those already have pages on this site, so this is the clause that ties the long-acting products to the compounds readers already know.
Beyond these, 140 records are indexed. Browse the records