HGH (Somatropin)

FDA Approved

Human Growth Hormone | Somatropin

Weight: 22,124 Da
Half-life: 3-4 hours (SC), 20-30 minutes (IV)
Chain: 191 amino acids
4 studies
2022 latest
2 recent
FDA Approved
Dose 1-4 IU daily (0.33-1.33mg); start low and titrate up
Frequency Once daily or split into 2 doses (morning and evening)
Cycle 3-6+ months or ongoing for medical GHD
Storage Lyophilized: Room temperature. Reconstituted: 2-8°C, use within 14-28 days

Community Research

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Human Growth Hormone (HGH/Somatropin) is a 191-amino acid polypeptide hormone FDA-approved for pediatric and adult growth hormone deficiency, HIV-associated wasting, and other conditions. It provides both direct and indirect (IGF-1 mediated) anabolic effects.

Mechanism of Action

Binds to GH receptors on target tissues, triggering JAK2-STAT5 signaling pathway. Direct effects include lipolysis, protein synthesis, and metabolic regulation. Indirect effects via IGF-1 promote growth and anabolism. Half-life ~3 hours subcutaneously.

01 Improved body composition (increased lean mass, decreased fat)
02 Enhanced bone mineral density
03 Improved lipid profile
04 Increased exercise capacity
05 Better quality of life and mood
06 Skin, hair, and nail improvements
07 Enhanced recovery and healing

Molecular Data

Molecular Weight
22,124 Da
Chain Length
191 amino acids
Type
Single-chain polypeptide with two disulfide bridges
Peak 0.0 mcg
Trough 0.0 mcg
SS Peak 0.0 mcg
SS Trough 0.0 mcg

Research Indications

Growth Hormone Deficiency
Pediatric GH Deficiency most effective

FDA-approved for idiopathic and organic causes, Turner syndrome, Prader-Willi syndrome, SGA, Noonan syndrome, SHOX deficiency.

Adult GH Deficiency most effective

FDA-approved for childhood-onset or adult-onset causes (pituitary tumors, surgery, radiation, trauma).

HIV-Associated Wasting effective

FDA-approved to increase lean body mass and body weight in cachexia.

Body Composition
Fat Loss effective

Significant fat loss especially abdominal/visceral fat over 1-3 months.

Lean Mass effective

Increased muscle mass and improved body composition.

Recovery Enhancement effective

Enhanced exercise recovery and tissue healing.

Anti-Aging
Skin and Hair Quality moderate

Improved skin elasticity, texture, and hair/nail growth.

Energy and Well-being moderate

Improved energy, sleep, and quality of life.

Dosing Protocols

Subcutaneous injection is the only effective route. Morning fasted injection maximizes fat-burning potential; evening mimics natural nocturnal GH pulse.

GoalDoseFrequencyRoute
Medical GHD (Starting)0.15-0.3mg/day (0.5-1 IU)Once dailySubQ
Medical GHD (Maintenance)0.4-0.8mg/day (1.2-2.4 IU)Once dailySubQ
Anti-Aging/Wellness1-2 IU/day (0.33-0.67mg)Once dailySubQ
Body Recomposition2-4 IU/day (0.67-1.33mg)Once or twice dailySubQ
Performance (Higher Risk)4-8 IU/day (1.33-2.67mg)Split twice dailySubQ

Reconstitution Instructions

Materials Needed:
  • HGH lyophilized powder vial (typically 10 IU or 36 IU)
  • Bacteriostatic water for injection
  • Insulin syringes (29-31 gauge)
  • Alcohol prep pads
  1. 1 Allow vial to reach room temperature (15-20 minutes)
  2. 2 Clean rubber stoppers with alcohol swab
  3. 3 Determine reconstitution volume (typical: 1mL BAC water per 10 IU)
  4. 4 Draw bacteriostatic water slowly, removing air bubbles
  5. 5 Insert needle at angle, aiming stream at vial wall - not directly on powder
  6. 6 Inject water slowly down inside wall, drop by drop
  7. 7 Remove needle and gently swirl in circular motion - never shake
  8. 8 Allow to sit if cloudy, then swirl again until crystal clear
  9. 9 Solution must be crystal clear; discard if cloudy or contains particles
  10. 10 Label with reconstitution date and concentration
  11. 11 Store refrigerated at 2-8°C; use within 14-28 days

Interactions

~
Insulin
HGH decreases insulin sensitivity; may require increased insulin doses in diabetics.
monitor
~
IGF-1/IGF-1 LR3
Synergistic but caution: enhanced effects with increased hypoglycemia and side effect risk.
monitor
~
Thyroid Hormones (T3/T4)
Increases T4 to T3 conversion; unmasks hypothyroidism in 36-47% of patients.
monitor
++
CJC-1295
GHRH analog can enhance effects though may be redundant with exogenous HGH.
synergistic
++
Ipamorelin
Ghrelin mimetic works via different pathway.
synergistic
++
GHRP-6/GHRP-2
Enhances natural pulsatile release.
synergistic
~
Cortisol/Hydrocortisone
Can unmask cortisol deficiency; replacement should precede HGH.
monitor
++
Testosterone
Commonly combined in hormone replacement therapy.
synergistic
~
Metformin
May manage insulin resistance; may reduce IGF-1 levels.
monitor
+
Semaglutide/Tirzepatide
GLP-1 agonists help manage insulin resistance during HGH therapy.
compatible

What to Expect

Week 1-2
Improved sleep quality, increased energy, possible water retention and joint stiffness
Week 2-4
Enhanced exercise recovery, skin improvement, possible carpal tunnel symptoms
Month 1-2
Noticeable fat loss (especially abdominal), improved skin elasticity and texture
Month 2-3
Continued fat loss, lean mass improvements, hair/nail growth, reduced recovery time
Month 3-6
Significant body composition changes, improved bone density, sustained energy/well-being
Long-term
Maintained benefits; effects diminish weeks-months after discontinuation

Side Effects & Safety

Common Side Effects

  • Water retention and fluid accumulation
  • Joint pain and stiffness
  • Carpal tunnel syndrome (usually resolves with dose reduction)
  • Headaches
  • Numbness/tingling in hands

Stop Signs - Discontinue if:

  • Severe or worsening carpal tunnel symptoms
  • Signs of diabetes (increased thirst, frequent urination, blurred vision)
  • Severe edema (facial, hand, or feet swelling)
  • Severe joint/muscle pain unresponsive to dose reduction
  • New lumps, masses, or rapidly growing moles
  • Severe headaches or vision changes
  • Signs of allergic reaction
  • Gynecomastia (breast tissue growth in males)
  • Hypothyroid symptoms (fatigue, weight gain, cold intolerance)

Contraindications

  • Active cancer (may accelerate tumor growth)
  • Acute critical illness (increased mortality in ICU patients)
  • Closed epiphyses in children (for growth promotion)
  • Pregnancy/breastfeeding

Quality Checklist

Good Signs

  • White to off-white lyophilized powder or solid cake (not liquid/collapsed)
  • Crystal clear reconstituted solution with no particles
  • Intact vacuum in sealed vial (resistance when inserting needle)
  • Pharmaceutical grade with certificate of analysis (Genotropin, Norditropin, Humatrope preferred)

Warning Signs

  • Generic/underground lab products have highly variable quality and potency
  • Common counterfeits exist; third-party testing recommended

Bad Signs

  • Cloudy, discolored, or particles visible indicates degradation
  • Powder appears melted or stuck to vial (improper storage)
  • Yellow/brown coloring

References

  • Long-term Safety of Growth Hormone in Adults With Growth Hormone Deficiency: Overview of 15,809 GH-Treated Patients
    Stochholm K, Kiess W, Gianetti E, et al.
    Journal of Clinical Endocrinology & Metabolism (2022)

    15,809 patients from the KIMS database, mean 5.3 years follow-up. Adverse events in 51.2% of patients, treatment-related in 18.8%. No correlation between GH dose and adverse event rate. Supports long-term safety of GH replacement in adults with GHD.

  • Efficacy and Safety of Growth Hormone Treatment in Adults with Growth Hormone Deficiency: A Systematic Review of Studies on Morbidity
    Defined a, Sääf M, et al.
    Clinical Endocrinology (2014)

    Systematic review demonstrating positive effects of GH treatment on cardiovascular disease and fracture risk, improvements in body composition, muscle strength, quality of life, bone mass/density, and lipoprotein patterns.

  • Cardiovascular Risk in Growth Hormone Deficiency: Beneficial Effects of Growth Hormone Replacement Therapy
    Gazzaruso C, Gola M, Karamouzis I, et al.
    Endocrine (2016)

    GH deficiency is associated with several cardiovascular risk factors that significantly increase cardiovascular morbidity and mortality. GH replacement improves cardiovascular risk factors.

  • Unmasking of Central Hypothyroidism Following Growth Hormone Replacement in Adult Hypopituitary Patients
    Agha A, Walker D, Perry L, et al.
    Clinical Endocrinology (2007)

    In 84 apparently euthyroid patients, 30 (36%) developed hypothyroidism requiring T4 therapy after starting GH. Highest risk in patients with organic pituitary disease or multiple pituitary hormone deficiencies.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.