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MK-677 (Ibutamoren) vs Somatropin (HGH)

Updated 13 sources

Key differences

  1. 1MK-677 makes the pituitary release its own GH; somatropin is GH itself and bypasses the pituitary.
  2. 2Guides say stopping MK-677 does not leave a rebound GH shortfall.
  3. 3MK-677 is an oral non-peptide pill that stimulates GH release; HGH is an injected protein.
  4. 4In one trial MK-677 25 mg a day raised IGF-1 from 141 to 265 ug/L over four weeks, per a guide's summary.

Side by side

Facts from each record, in the same words as their own pages.
MK-677 (Ibutamoren) and Somatropin (HGH) side by side
MK-677 (Ibutamoren)Somatropin (HGH)
Category
  • GH axis
  • GH axis
Evidence
  • Some human trials
  • Strong human trials
FDA status
  • FDA 503A Category 2Regulatory
  • FDA approved as Genotropin +7Regulatory
WADA
  • Prohibited
  • Prohibited
Half-life
  • About 4 to 6 hours, measured in beagles; no human plasma half-life in the sources.Reference work
  • About 24 hours, per most guides. That figure tracks how long the effect lasts more than plasma levels.Competitor guide
  • About 3 hours after a subcutaneous dose in adults with GH deficiency; 0.4 hours when given IV. The longer SC figure reflects slow absorption.Regulatory
  • 3.8 hours after a subcutaneous dose in healthy adults (Humatrope).Regulatory
  • 2.5 to 2.8 hours after a subcutaneous dose in healthy adults (Omnitrope).Regulatory
Routes
  • Oral
  • Subcutaneous injection
Forms
  • Capsule, Oral solution
  • Vial (powder), Prefilled pen
Reported doses
  • 2 to 25 mg (oral)
  • 0.8 to 3.2 mg/kg (oral)
  • 0.15 to 0.3 mg (subcutaneous injection)
  • 0.004 to 0.1 mg/kg (subcutaneous injection)
  • 1 to 8 IU (subcutaneous injection)
Most cited frequency
  • Once daily
  • Once daily; raise by about 0.1 to 0.2 mg/day every 1 to 2 months
Vial sizesNot reported
  • 5.8 mg, 5 mg, 10 mg, 4 IU, 10 IU, 12 IURegulatory
Mixed vial keepsNot reported
  • Genotropin cartridge after mixing: fridge at 2 to 8 C for up to 28 days, protected from light.Regulatory
Protocols on file
  • 16
  • 10

Doses shown are what sources report, labelled by origin. Not medical advice.

Read each in full

Sources

13 sources, each checked by date. Record updated Oct 24, 2026. Numbers are restated in our own words and labelled by where they came from.

Regulatory7

  1. Genotropin (somatropin) prescribing informationDailyMed · checked Oct 24, 2026
  2. Humatrope (somatropin) prescribing informationDailyMed · checked Oct 24, 2026
  3. Omnitrope (somatropin) prescribing informationDailyMed · checked Oct 24, 2026
  4. Certain bulk drug substances that may present significant safety risksFDA · checked Oct 24, 2026

Reference work1

  1. IbutamorenWikipedia · checked Oct 24, 2026

Competitor guide5

  1. MK-677PeptidesExplorer · checked Oct 24, 2026
  2. HGH vs Peptidespeptidesexplorer.com · checked Oct 24, 2026
  3. MK-677 (Ibutamoren) protocol guidePathToPeptides · checked Oct 24, 2026
  4. MK-677 (Ibutamoren) dosage guideBodyHackGuide · checked Oct 24, 2026