How Growth Hormone Affects Blood Glucose

Growth hormone (GH) exerts potent anti-insulin effects through several mechanisms:

1. Hepatic gluconeogenesis: GH stimulates the liver to produce glucose from non-carbohydrate substrates (amino acids, lactate, glycerol), increasing hepatic glucose output.
2. Peripheral insulin resistance: GH reduces glucose uptake in skeletal muscle and adipose tissue by impairing insulin signalling (specifically, reducing IRS-1 phosphorylation and GLUT4 translocation).
3. Lipolysis: GH promotes fat breakdown, releasing free fatty acids (FFAs). Elevated FFAs further impair insulin sensitivity through the Randle cycle (fatty acid-glucose competition for oxidation).
4. Pancreatic beta-cell stress: Chronic insulin resistance from sustained GH use forces the pancreas to produce more insulin (hyperinsulinemia). Over time, this can exhaust beta-cell capacity.

These effects are physiologically intentional: GH is a "fasting hormone" that mobilises energy stores. However, when exogenous GH is used chronically, these mechanisms push glucose metabolism toward diabetic territory.

Low-dose (1-3 IU/day):

• Fasting glucose may rise 5-15 mg/dL above baseline
• Most users remain in the normal range (below 100 mg/dL)
• Insulin sensitivity mildly impaired but generally manageable

Moderate doses (4-6 IU/day):

• Fasting glucose commonly rises to 95-115 mg/dL
• Some users enter the pre-diabetic range (100-125 mg/dL)
• HbA1c may rise to 5.5-5.9%
• Fasting insulin levels increase as the pancreas compensates

High doses (8-15+ IU/day):

• Fasting glucose frequently exceeds 110-130 mg/dL
• HbA1c can rise above 6.0%
• Frank insulin resistance develops in many users
• Some users develop type 2 diabetes, especially with concurrent insulin use or poor diet

Timeline: Glucose elevation begins within 1-2 weeks of starting GH. The effect is cumulative; the longer the duration, the more pronounced the insulin resistance.

Baseline: Obtain fasting glucose, fasting insulin, and HbA1c before starting GH. If HbA1c is already above 5.6%, GH use will likely push you into pre-diabetic territory.

During use:

• Fasting glucose: monthly for the first 3 months, then every 3 months
• HbA1c: every 3 months (reflects average glucose over 2-3 months)
• Fasting insulin: every 3-6 months (early indicator of compensatory hyperinsulinemia)
• Consider a glucose tolerance test (OGTT) if fasting glucose is borderline

Warning signs that warrant dose reduction or cessation:

• Fasting glucose consistently above 110 mg/dL
• HbA1c above 5.7%
• Fasting insulin above 15-20 mIU/L
• Symptoms: excessive thirst, frequent urination, fatigue after meals

Diet optimisation:

• Reduce simple carbohydrates and focus on complex, low-glycemic sources
• Increase fibre intake (30-40 g/day) to slow glucose absorption
• Time carbohydrate intake around training when insulin sensitivity is highest
• Consider carb-cycling: lower carbs on rest days, higher around workouts

Supplements that support glucose metabolism:

• Berberine 500 mg 2-3x daily with meals (evidence-based insulin sensitiser)
• Chromium picolinate 200-1000 mcg/day
• Alpha-lipoic acid 300-600 mg/day
• Cinnamon extract (Ceylon) 1-3 g/day

Timing strategies:

• Some users inject GH at night to minimise daytime glucose disruption
• Fasted morning injection may worsen morning glucose (dawn phenomenon + GH effect)
• Splitting the dose (half AM, half PM) may reduce peak glucose impact

If glucose becomes problematic:

• Reduce GH dose by 25-50%
• Metformin 500-1000 mg/day (prescription) is the most effective pharmaceutical intervention for GH-induced insulin resistance
• Do not add exogenous insulin to "offset" GH glucose effects unless under close medical supervision; this is a high-risk strategy