galcanezumab
Emgality (galcanezumab) is a monoclonal antibody from Eli Lilly that binds and neutralizes calcitonin gene-related peptide (CGRP), a key signaling molecule in migraine. Given once monthly by injection, it prevents migraine in adults and treats episodic cluster headache.
This page is based on FDA prescribing information and the EMA medicine record for galcanezumab, cross-checked with DailyMed; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
During a migraine or cluster headache attack, the brain's pain system floods the surrounding nerves and blood vessels with a chemical called CGRP, like turning up the volume on a fire alarm. Galcanezumab acts like a sponge that soaks up that chemical before it can reach its receivers, keeping the volume down and preventing attacks.
In simple terms
Galcanezumab is an antibody that targets calcitonin gene-related peptide (CGRP), a small protein released during migraine and cluster headache attacks. CGRP causes blood vessels around the brain to widen and pain signals to intensify. By binding and neutralizing CGRP itself, galcanezumab reduces the frequency of migraine attacks and, in cluster headache, shortens the episode cycle. It is given as a monthly injection for prevention — it does not treat an attack that has already begun.
In depth
Galcanezumab is a humanized IgG1 monoclonal antibody that binds the CGRP ligand with high affinity, preventing it from engaging the CGRP receptor (CALCRL/RAMP1 complex). Unlike receptor-directed antibodies such as erenumab, galcanezumab neutralizes the ligand itself, blocking downstream Gs-protein signaling, cAMP production, and trigeminovascular activation in both migraine and cluster headache. The long half-life supports monthly subcutaneous dosing. In episodic cluster headache, neutralizing CGRP reduces the autonomic and pain features driven by hypothalamic–trigeminal activation.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How galcanezumab neutralises CGRP to prevent migraine and cluster headache
- During a migraine or cluster headache attack, the brain's pain system floods the surrounding nerves and blood vessels with a chemical called CGRP, like turning up the volume on a fire alarm.
- Galcanezumab is a humanized IgG1 monoclonal antibody that binds the CGRP ligand with high affinity, preventing it from engaging the CGRP receptor (CALCRL/RAMP1 complex).
- By binding and neutralizing CGRP itself, galcanezumab reduces the frequency of migraine attacks and, in cluster headache, shortens the episode cycle.
- In episodic cluster headache, neutralizing CGRP reduces the autonomic and pain features driven by hypothalamic–trigeminal activation.
Target: Calcitonin gene-related peptide (CGRP)
A 37-amino-acid neuropeptide released from trigeminal nerves during migraine and cluster headache attacks; it widens blood vessels and amplifies pain signaling. Neutralizing it dampens the attack cascade.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- Preventive treatment of migraine in adults
- Treatment of episodic cluster headache in adults
Approved uses in European Union
EMA- Prophylaxis of migraine in adults who have at least 4 migraine days per month
Official sources
The statements on this page trace back to these records.
- U.S. Food and Drug Administration: galcanezumab prescribing information
U.S. Food and Drug Administration
- Emgality (galcanezumab) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- DailyMed: Emgality (galcanezumab) prescribing information
DailyMed, U.S. National Library of Medicine
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.