GHRP-2 may stimulate appetite and food intake in healthy men according to research data

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

Purpose of the study

To assess whether the peptide GHRP-2 (Growth Hormone Releasing Peptide-2) – a synthetic analogue of the hormone ghrelin – can increase appetite and food consumption in healthy people.

Ghrelin is the first peripheral hormone to directly stimulate hunger. It is produced primarily in the stomach and acts through GHS-R1a receptors to increase growth hormone (GH) levels and stimulate feeding.

The aim of this study was to test whether GHRP-2, which shares the same receptor, could mimic the effects of ghrelin in humans.

Study design

Type: double-blind, placebo-controlled, crossover
Participants: 7 healthy men (mean age 26 years, 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
Nutritional test: after the end of the infusion, participants are given access to a free-choice buffet to measure spontaneous energy intake
Measurements:
- Energy intake (total calorie intake, macronutrients)
- GH, glucose, insulin levels
- Subjective feeling of hunger (visual scales)

Main results

Food intake

GHRP-2 leads to a significant increase in energy intake:
- +35.9% vs. placebo
- GHRP-2: 136.0 ± 13.0 kJ/kg
- Placebo: 101.3 ± 10.5 kJ/kg ( p = 0.008 )
The composition of the food (proteins, carbohydrates, fats) does not differ significantly.
Participants began eating earlier after the GHRP-2 infusion.

Hormonal response

GH rises sharply during infusion:
- GHRP-2: 5550 ± 1090 µg/L/240 min
- Placebo: 412 ± 161 µg/L/240 min ( p = 0.003 )
Insulin and glucose remain stable.
No side effects were observed.

Subjective sensations

The feeling of hunger and desire to eat increases synchronously with the increase in GH.
The effect is temporary and disappears 1–2 hours after stopping the infusion.

Conclusions

GHRP-2 stimulates food intake in healthy people.
This is the first evidence that a peptide activating the GHS-R1a receptor can induce real hunger and increased calorie 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 – stimulation of appetite and anabolism.