Fasting and HGH

Fasting can raise growth hormone (HGH), but a higher level does not necessarily mean a greater growth-hormone effect; sleep and meal timing matter too.

• Fasting and ghrelin: Fasting can roughly double waking growth-hormone levels. Hunger-related ghrelin can activate the receptor normally used by growth-hormone-releasing hormone, stimulating growth-hormone release. 1
• Food before bed: Avoiding food for about two hours before sleep may support the normal overnight growth-hormone pulse. 2
• Prolonged fasting: Although fasting raises growth hormone, receptor sensitivity and downstream signaling may be reduced, so extended fasting specifically to optimize growth hormone may not deliver the expected benefit. 3
• Sleep and meal timing: Growth hormone is released during early-night deep sleep. Quality sleep and avoiding food close to bedtime may support that release; carbohydrate-heavy meals can blunt the overnight peak. 4
• Intermittent fasting: Intermittent fasting may increase growth hormone and IGF-1, with a potentially greater benefit in older adults. The overnight pulse still occurs with a relatively short pre-sleep fast, while longer fasting brings diminishing returns. 5