Since GH is released into the blood in pulses throughout the day, it is difficult to interpret
the results from a single GH test. IGF-1 mirrors GH excesses and deficiencies, but unlike GH,
its level is stable throughout the day. This makes IGF-1 a useful indicator of average GH
levels. The IGF-1 test is therefore often used to help evaluate for GH deficiency or GH excess.
High IGF-1 can be caused by:
• GH-producing pituitary tumor (usually benign) [R]
• Pregnancy (this is normal) [R]
Symptoms of high IGF-1 associated with GH-producing tumors (acromegaly), include
[R]:
• Headache
• Sweating
• Carpal tunnel syndrome
• Joint pain
• Deepening of the voice
If the condition is caused by an underlying disorder, seek medical attention.
Fasting and calorie restriction can help lower IGF-1 levels [R, R, R].
Increase the proportion of carbs in your diet. A higher proportion of carbohydrates is
associated with lower IGF-1 [R].
Restrict the amount of protein in your diet [R].
Lycopene found in tomatoes, guava, rosehip, watermelon, papaya, apricot, and pink
grapefruit can help decrease IGF-1 levels [R].
Supplements that can help:
• Royal jelly [R]
• Glucosamine [R]
• Luteolin [R]
• Curcumin [R]
• Resveratrol [R]
• Genistein [R]
• Apigenin [R, R]
• Lycopene [R]
• EGCG [R]
• Boron [R]