Growth Hormone

Somatropin

HGH · rhGH · recombinant human growth hormone · Omnitrope · Genotropin · Humatrope

191-amino-acid recombinant human growth hormone. FDA-approved for GHD and other labeled indications (Omnitrope, Genotropin, Humatrope, Saizen). This is the hormone itself - not a secretagogue. Labels use 1 mg = 3 IU. WADA S2 at all times. Lyophilized research vials need IU reconstitution math; branded pens are already liquid.

WADA (S2) - prohibited in sport at all times

Quick answer

What it is: 191-amino-acid recombinant human growth hormone.

Typical research dose: Prescription is weight/indication-based; research vials often 1-4 IU/day. Conversion: 1 mg = 3 IU (WHO somatropin standard)

Reconstitution calculator ↓Sermorelin online: providers and cost →Telehealth clinics that prescribe peptides →

Research summary, not medical advice.

Reviewed by Kymata Health Editorial Team

·Last updated: August 2026·Evidence: High·1 peer-reviewed citation

Typical research dose

Prescription is weight/indication-based; research vials often 1-4 IU/day. Conversion: 1 mg = 3 IU (WHO somatropin standard)

Frequency

1× daily (evening SC) on labeled products

Half-life

~3 hours SC; ~0.4 hours IV (Omnitrope PI)

Common vials

10 IU / 15 IU / 30 IU

CAS

12629-01-5

Molecular weight

~22 kDa

Use-case scores

0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.

Muscle / recomp8/10
Approved rhGH with decades of labeled GHD/other indications. Ceiling 9; haircut because abuse/research vials are not Omnitrope and WADA S2 is not optional.

Compound card

Sequence: 191-aa recombinant human GH
Class: Prescription somatropin (not a secretagogue)
Formula: Recombinant 191-aa GH
Status: FDA-approved

Dose it

10 IU + 1 mL BAC water → 10 IU/mL · 1 IU ≈ 10.0 units (U-100)

Open in calculator

How it works

Somatropin is 191-aa recombinant human GH. FDA-approved products (Omnitrope, Genotropin, Humatrope, Saizen, Norditropin, etc.) are calibrated at 1 mg = 3 IU against the WHO somatropin standard.

IV t½ is ~0.4 hours; SC t½ is ~3 hours because of depot absorption. This page is for lyophilized vials labeled in IU. Brand pens are already in solution - do not force pen math through a powder calculator.

Source: Omnitrope PI (1 mg = 3 IU; SC t½ ~3 h); FDA somatropin class labeling

1 mg = 3 IU. Calculator is in IU.

A 10 IU vial + 1 mL is 10 IU/mL. On a U-100 syringe, 1 unit = 0.1 IU, so 2 IU is 20 units. If your vial is labeled in mg, multiply mg × 3 to get IU, then use IU mode. Do not treat 5 mg as “5” in this calculator unless you converted.

Research Use Cases

✓Documented GHD / labeled indications: High
✓Secretagogue alternative: Low

Dosing

Phase	Dose	Frequency	Notes
Labeled adult/pediatric GHD	Weight- and indication-based (PI)	Daily SC on most products	Do not copy forum IU numbers onto a labeled deficiency diagnosis.
Lyophilized research vial (IU math only)	1–4 IU/day is a common unlabeled range	Once daily	Unapproved use. IGF-1, glucose, and fluid retention monitoring belong with a clinician.

Administration

Route / form

Subcutaneous (labeled). Rotate sites (lipoatrophy).

Timing

Evening on many labeled schedules to mimic nocturnal GH.

Empty stomach?

No - Food timing is not critical.

Somatropin: Lyophilized IU vial vs Branded liquid pen

Lyophilized IU vial

Bioavailability

SC absorption stretches apparent t½ to about 3 hours versus ~0.4 h IV (Omnitrope PI class). That is labeled somatropin, not a secretagogue. Conversion is 1 mg = 3 IU (WHO somatropin standard).

Dose note

Reconstitute the IU-labeled cake. Example: 10 IU + 1 mL → 10 IU/mL; 2 IU = 0.20 mL = 20 units on a U-100. If the vial is in mg, multiply mg × 3 to get IU first. Do not treat “5 mg” as “5” in IU mode.

Advantages

This is the column the reconstitution calculator is for.
IU math is checkable when the bottle is actually lyophilized somatropin.

Considerations

Research cakes are not Omnitrope. WADA S2 at all times.
Labeled GHD doses are not forum 2–4 IU “anti-aging.”
IU ≠ mcg. Do not paste a BPC unit chart onto GH.

Branded liquid pen

Bioavailability

Norditropin FlexPro, Genotropin MiniQuick, and similar pens are already in solution. Label PK is for that finished product. It is still somatropin. It is not a 10 IU cake.

Dose note

Follow the pen click-chart. Do not add BAC water. Do not force pen math through a powder calculator. If you switched from a cake, restart from the insert, not from leftover unit arithmetic.

Advantages

No reconstitution. Device dosing is the labeled job.
Pharmacovigilance and fill belong to the brand, not a gray-market lyophilized lot.

Considerations

Pens do not get BAC recon charts. Putting a FlexPro in the powder calculator is the bug.
Still prescription GH. Still WADA S2. Still a malignancy contraindication class.

Recommendation: Somatropin is the hormone. Lyophilized IU vials get recon math (1 mg = 3 IU). Branded pens are already liquid and do not get BAC charts. Secretagogues are a different aisle. IU ≠ mcg.

Timeline

Days–weeks

IGF-1 rise, fluid retention, joint stiffness possible.

Months

Body-composition and (in GHD) clinical endpoints are labeled trial results - not this calculator.

Who it is for

Documented GHD / labeled indications

High

This is a prescription biologic with decades of PI data.

Secretagogue alternative

Low

CJC/ipa and sermorelin try to pulse endogenous GH. Somatropin is exogenous hormone. Different suppression and IGF-1 profiles.

Reconstitution

Vial	Water	Concentration	Example dose
10 IU lyophilized	1.0 mL BAC/sterile per product	10 IU/mL	2 IU = 0.20 mL = 20 units on a U-100. Convert mg × 3 if the vial is in mg.

Change vial size or water volume? Open the reconstitution calculator.

Safety & Considerations

Prescription GH. Contraindications include active malignancy. Adverse effects include edema, arthralgia, carpal-tunnel symptoms, insulin resistance. WADA S2. Never share pens or vials.

Regulatory & Legal Status

FDA Status (US)

Approved

FDA-approved recombinant GH (Omnitrope®, Genotropin®, Humatrope®, Saizen®, others). 1 mg = 3 IU

WADA Status (2026)

Prohibited (S2)

Competitive athletes subject to anti-doping controls should not use Somatropin.

Classification

Prescription Drug

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Limits of current evidence

Labeled GHD doses are not forum 2–4 IU “anti-aging.”
This calculator is for IU-labeled lyophilized vials, not branded pens.
Active malignancy is a class contraindication. This page is not a prescription.

Verdict

Somatropin is the hormone. Secretagogues try to make you pulse your own. IU math is 1 mg = 3 IU. Pens are already liquid. WADA S2.

Interactions & Contraindications

Prescription GH. Contraindications include active malignancy. Adverse effects include edema, arthralgia, carpal-tunnel symptoms, insulin resistance. WADA S2. Never share pens or vials.

Somatropin vs. CJC-1295 (no DAC)

Canonical comparison: Somatropin vs CJC-1295 (no DAC)

Attribute	Somatropin	CJC-1295 (no DAC)
What it is	Exogenous 191-aa GH	GHRH analog (secretagogue)
Units	IU (1 mg = 3 IU)	mcg
FDA	Approved (multiple brands)	Research / compounding
WADA	S2	S2
Feedback	Can suppress endogenous GH	Intended to pulse endogenous GH

Verdict: Somatropin is the hormone. CJC is a releasing-hormone analog. Different calculator units, different endocrine consequences.

Frequently Asked Questions

Pen or lyophilized IU vial?▼

Lyophilized vials are labeled in IU (1 mg = 3 IU) and belong in the reconstitution calculator. Branded pens are already liquid. Do not BAC-reconstitute a FlexPro. IU ≠ mcg. This is the hormone, not a secretagogue.

How do I convert a 5 mg vial to IU?▼

5 mg × 3 = 15 IU. Then reconstitute 15 IU with your chosen mL and dose in IU.

Is this the same as CJC-1295?▼

No. CJC is a GHRH analog (secretagogue). Somatropin is GH itself.

Can I use the mcg calculator?▼

Not for IU-labeled vials. mcg mode multiplies mass by 1,000 and will print a wrong draw.