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

Reviewed by CalcMyPeptide Editorial Team

·Last updated: April 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

Dose it

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

Open in calculator

Mechanism of Action

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.

Dosing Protocol

Typical 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 terminal; ~0.4 h IV)
Common Vial Sizes	10 IU, 15 IU, 30 IU

Dosing Protocols

Labeled adult/pediatric GHD

Dose

Weight- and indication-based (PI)

Frequency

Daily SC on most products

Note: Do not copy forum IU numbers onto a labeled deficiency diagnosis.

Lyophilized research vial (IU math only)

Dose

1–4 IU/day is a common unlabeled range

Frequency

Once daily

Note: Unapproved use. IGF-1, glucose, and fluid retention monitoring belong with a clinician.

Administration

Route

Subcutaneous (labeled). Rotate sites (lipoatrophy).

Timing

Evening on many labeled schedules to mimic nocturnal GH.

Fasting Required?

No — food timing not critical

Expected 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 Is It 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 Example

Vial

10 IU

Diluent

1 mL

Concentration

10 IU/mL

Per Unit (100u syringe)

0.1 IU

Dose of 1 IU = 10 units on a 100-unit insulin syringe · IU mode (no mg→mcg conversion)

🧮 Calculate Your Exact Somatropin Dose →

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.

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.

Dosing Quick Reference

Somatropin— Dosing Guide

Dose Range

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

Half-Life

~3 hours (SC terminal; ~0.4 h IV)

Frequency

1× daily (evening SC) on labeled products

Route

Subcutaneous

10 IU vial15 IU vial30 IU vial

💧 1 mL BAC water|📐 10 IU/mL|💉 0.1 IU/unit (100u syringe)

Growth Hormonecalcmypeptide.com

Frequently Asked Questions

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.

References

Sandoz “Omnitrope (somatropin) prescribing information — 1 mg = 3 IU; SC t½ ~3 h.” Product PI (current).

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