How can I stimulate Insulin-like Growth Factor 1 (IGF-1) production in myself?

How to Stimulate IGF-1 Production

The most effective methods to increase IGF-1 levels are resistance/strength training combined with adequate nutrition, growth hormone therapy, or direct recombinant human IGF-1 (rhIGF-1) administration, though the latter two carry significant risks and are only indicated for specific medical conditions. 1, 2, 3

Non-Pharmacological Approaches (Safest and First-Line)

Resistance Training and Exercise

• Strength training selectively increases fat-free mass by stimulating protein synthesis via IGF-1 or targets downstream of IGF-1 signaling. 1
• Whole body exercise training for 8 weeks increases body weight through modest increases in fat-free mass, mediated by IGF-1 pathways. 1
• Aerobic training combined with strength training for 12 weeks enhances muscle cross-sectional area through IGF-1-dependent mechanisms. 1

Nutritional Optimization

• Adequate protein intake is crucial for stimulation of protein synthesis and IGF-1 production to maintain or restore fat-free mass. 1
• IGF-I production signals the availability of nutrients needed for its anabolic actions, with serum concentrations falling in malnutrition and responding promptly to refeeding. 4
• Caloric supplementation combined with supervised exercise training increases body weight and fat-free mass through IGF-1 mediated pathways. 1
• Energy-dense supplements and adaptation of dietary habits optimize IGF-1 production when combined with physical activity. 1

Pharmacological Approaches (Medical Supervision Required)

Growth Hormone Therapy

• Growth hormone is a potent stimulator of systemic IGF-1 levels and has been shown to increase lean body mass in clinical studies. 1, 2
• Growth hormone activates cardiac cell growth and induces physiological ventricular remodeling through IGF-1 mediated mechanisms. 2
• Studies are ongoing to investigate growth hormone-releasing factors that work by stimulating endogenous IGF-1 production. 2

Critical Warning: Growth hormone therapy is expensive and associated with undesirable side effects including salt and water retention, impairment in glucose metabolism, and chronic excess can result in biventricular cardiac hypertrophy progressing to dilated cardiomyopathy. 1, 2

Direct IGF-1 Replacement

• Recombinant human IGF-1 (rhIGF-1) administration directly increases IGF-1 levels and bone formation markers. 1, 2
• In clinical trials, rhIGF-1 combined with estrogen led to a 2.8% significant increase in bone mineral density. 1, 2
• Treatment with rhIGF-1 stimulates linear growth in children with severe IGF-1 deficiency, with height velocity increasing from 2.8 cm/yr to 8.0 cm/yr during the first year. 3

Critical Warning: The most common adverse event with rhIGF-1 is hypoglycemia (reported by 49% of subjects), followed by injection site lipohypertrophy (32%) and tonsillar/adenoidal hypertrophy (22%). 3

Anabolic Steroids

• Low-dose anabolic steroids increase fat-free mass through mechanisms that include modulation of the IGF-1 system and regulation of the myostatin gene. 1, 2
• Anabolic steroids may improve outcomes through stimulation of protein synthesis either directly or indirectly by interaction with the IGF-1 system. 1, 2
• In male patients with low testosterone levels, testosterone administration increases muscle mass, with effects augmented by concomitant resistance training. 1

Factors That Suppress IGF-1 (Avoid These)

Oral Estrogen

• Oral estrogen suppresses hepatic IGF-1 production through first-pass liver metabolism, upregulating synthesis of IGF-1 binding proteins (IGFBP-1) that further reduce IGF-1 bioavailability. 1, 2
• This suppression is particularly problematic in individuals who already have low endogenous IGF-1 concentrations. 1, 2
• Transdermal estradiol circumvents hepatic first-pass metabolism and therefore does not suppress IGF-1 production like oral estrogen. 2

Nutritional Deficiencies

• Severe hypothyroidism, malnutrition, or low energy states suppress IGF-1 generation. 1, 5
• Hepatic or renal failure may affect IGF-1 measurements and production. 1, 5

Clinical Monitoring Considerations

• IGF-1 must be interpreted against age-matched, sex-matched reference ranges because levels decline substantially with aging. 5
• Inter-assay variability is substantial for IGF-1 measurements, requiring the use of laboratory-specific reference ranges. 5
• Poorly controlled diabetes mellitus can cause falsely elevated IGF-1 levels. 1, 5