GHRP-2 can stimulate appetite and food intake in healthy men, according to scientific research data.

Source: Laferrère B. et al., The Journal of Clinical Endocrinology & Metabolism, 2005, PMC2824650


Study Objective

To evaluate whether the peptide GHRP-2 (Growth Hormone Releasing Peptide-2) – a synthetic analog of the hormone ghrelin – can increase appetite and food intake in healthy individuals.

Ghrelin is the first peripheral hormone that directly stimulates hunger. It is mainly produced in the stomach and acts through GHS-R1a receptors, increasing growth hormone (GH) levels and stimulating feeding.

The aim of this study is to investigate whether GHRP-2, which shares the same receptor, can mimic the effects of ghrelin in humans.



Study Design

  • Type: double-blind, placebo-controlled, crossover

  • Participants: 7 healthy men (mean age 26 y, BMI 22.8 kg/m²)

  • Interventions:


    • GHRP-2 infusion (1 µg/kg/hour) for 270 minutes

    • Control session: placebo (0.9% NaCl) of the same duration


  • Feeding test: after the end of the infusion, participants had access to a buffet with free choice, to measure spontaneous energy intake

  • Measurements:


    • Energy intake (total caloric intake, macronutrients)

    • GH, glucose, insulin levels

    • Subjective feeling of hunger (visual scales)


Key Findings

Food intake


  • GHRP-2 led to a significant increase in energy intake:


    • +35.9% compared to placebo

    • GHRP-2: 136.0 ± 13.0 kJ/kg

    • Placebo: 101.3 ± 10.5 kJ/kg (p = 0.008)


  • Food composition (proteins, carbohydrates, fats) did not differ significantly.

  • Participants started eating earlier after GHRP-2 infusion.



Hormonal response

  • GH sharply increased during infusion:

    • GHRP-2: 5550 ± 1090 µg/L/240 min

    • Placebo: 412 ± 161 µg/L/240 min (p = 0.003)


  • Insulin and glucose remained stable.

  • No side effects were observed.



Subjective sensations

  • Feelings of hunger and desire to eat increased synchronously with the rise in GH.

  • The effect was temporary and disappeared 1–2 hours after stopping the infusion.



Conclusions

  • GHRP-2 stimulates food intake in healthy individuals.

  • This is the first evidence that a peptide activating the GHS-R1a receptor can induce real hunger and increased caloric intake.

  • It acts centrally (in the hypothalamus) and peripherally, activating neural pathways related to appetite.

  • It has potential use in conditions with reduced appetite (anorexia, cachexia, sarcopenia).

  • The effect on GH indicates a possible dual benefit – appetite stimulation and anabolism.



Limitations

  • Small number of participants (n=7)

  • Only men with normal weight

  • Single infusion – does not show long-term effect

  • Not studied in overweight individuals



Practical Implications

  • GHRP-2 could be used in clinical conditions with reduced appetite.

  • It increases GH and may support recovery and muscle growth.

  • Its action is short-lived and controllable, suitable for research purposes.