Source: Laferrère B. et al., The Journal of Clinical Endocrinology & Metabolism, 2005, PMC2824650
The aim of the study is to evaluate whether GHRP-2 (Growth Hormone-Releasing Peptide-2), a synthetic agonist of the ghrelin receptor GHS-R1a, can affect appetite and actual food intake in healthy individuals.
Ghrelin is a peripheral hormone produced mainly in the stomach, which participates in the regulation of hunger and energy balance. In addition, activation of GHS-R1a receptors stimulates the release of growth hormone (GH).
The researchers examine whether GHRP-2, which activates the same receptor system, can cause a measurable increase in appetite and spontaneous caloric intake in humans.
Type: double-blind, placebo-controlled, crossover clinical study.
Participants: 7 healthy men with a mean age of approximately 26 years and a mean BMI of 22.8 kg/m².
Interventions:
infusion of GHRP-2 at 1 µg/kg/hour for 270 minutes;
control session with placebo – 0.9% NaCl – of the same duration.
Feeding Test: after the infusion, participants receive free access to a buffet, allowing spontaneous energy intake to be measured.
Monitored Parameters:
total caloric intake and macronutrient distribution;
GH, glucose and insulin concentrations;
subjective feeling of hunger and desire to eat via visual analog scales.
Food Intake
During the GHRP-2 session, a significant increase in spontaneously ingested energy was reported compared to placebo.
an increase of approximately 35.9%;
GHRP-2: 136.0 ± 13.0 kJ/kg;
placebo: 101.3 ± 10.5 kJ/kg (p = 0.008).
No significant change was found in the relative distribution of proteins, carbohydrates and fats.
Participants demonstrated a stronger urge to start eating after exposure to GHRP-2.
Hormonal Response
GHRP-2 caused a clearly pronounced increase in growth hormone secretion compared to placebo.
GHRP-2: 5550 ± 1090 µg/L/240 min;
placebo: 412 ± 161 µg/L/240 min (p = 0.003).
Within the observation period, no significant changes in plasma glucose or insulin were found.
In this small and short-term study, no significant adverse reactions were reported.
Subjective Sensations
Participants reported increased feelings of hunger and a stronger desire to eat during exposure to GHRP-2.
The effect is transient and gradually diminishes after cessation of the infusion.
GHRP-2 shows the ability to increase spontaneous food intake in healthy participants under controlled experimental conditions.
The results support the role of the GHS-R1a receptor system in regulating appetite in humans.
At the same time, a strongly pronounced GH response was observed, confirming the characteristic activity of GHRP-2 on pituitary secretion.
The study provides a basis for further research into conditions characterized by reduced appetite and loss of body mass.
The results do not allow conclusions to be drawn regarding long-term anabolic, recovery, or clinical effects.
a very small number of participants – only 7 individuals;
only young men with normal body weight are included;
a short-term intravenous infusion was studied, not prolonged exposure;
the study does not evaluate long-term changes in body weight or body composition;
the results cannot be directly transferred to people with obesity, cachexia, or other diseases.
The study shows that activation of GHS-R1a via GHRP-2 can lead to a measurable increase in hunger and food intake in humans.
The observed effect on GH confirms that the molecule simultaneously affects pituitary GH secretion and mechanisms related to appetite.
The data are of interest for further clinical research into conditions with impaired appetite, but do not alone prove therapeutic efficacy.
Due to the small size and short duration of the study, significantly larger controlled studies are needed before conclusions can be drawn regarding clinical application.
The information presents the results of a specific scientific study and is for educational and informational purposes only. It does not constitute medical advice, a treatment recommendation, instructions for use, or dosing guidance.