Ghrelin

Ghrelin (Growth Hormone-Releasing Peptide, Endogenous)

Evidence & Status

  • Strong Human Evidence
  • Strong

At a Glance

The body's principal hunger-signaling hormone, a 28-amino-acid peptide secreted primarily by the stomach that simultaneously stimulates appetite and triggers growth hormone release. Widely studied in appetite regulation, energy balance, metabolic biology, and the neuroscience of hunger and reward.

Plain English

Researchers study Ghrelin because it is the primary signal the body uses to communicate hunger to the brain. Scientists are interested in how Ghrelin influences not only appetite but also metabolism, growth hormone secretion, and mood and reward pathways. Understanding how Ghrelin works is considered foundational to understanding obesity, eating disorders, and how the body regulates energy balance. It is also the natural ligand — the body's own molecule — for the receptor that compounds such as Ipamorelin, GHRP-6, and MK-677 are designed to activate.

Overview

The endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a), discovered in 1999. A 28-amino-acid acylated peptide produced primarily in gastric oxyntic cells. Acts as the primary endogenous stimulator of GH secretion and is the only known circulating hormone that promotes appetite. Also studied for gastric motility, cardioprotection, and energy homeostasis regulation.

Research Summary

Ghrelin was discovered as an acylated endogenous ligand for the growth-hormone secretagogue receptor. Its active form requires Ser3 octanoylation, and its established human evidence concerns endogenous appetite, growth-hormone, and energy-homeostasis physiology. Cardiovascular, gastrointestinal, and immune topics remain research areas and should not be represented as broad therapeutic efficacy. This strong physiology evidence does not establish a universal exogenous dosing, pharmacokinetic, safety, or therapeutic-efficacy profile.

Research Areas

  • GH secretion
  • Appetite regulation
  • Gastric motility
  • Energy homeostasis
  • Cardioprotection
  • Sleep regulation

Safety & Risks

Serious Risks

  • Safety of exogenous administration is not established for every population, dose, or condition
  • Supraphysiologic exposure may dysregulate appetite and metabolic homeostasis

Reported Side Effects

  • Hunger and increased appetite
  • Transient nausea
  • Mild cortisol elevation
  • Transient insulin resistance
United States
Research only
United Kingdom
Research only
Australia
Research only
Canada
Research only

Citations & Sources