What is the practical difference between binding the receptor and the ligand?

The labels state the mechanisms without ranking them: Aimovig antagonizes the CGRP receptor, Emgality intercepts the CGRP molecule before it reaches the receptor. Neither document claims an advantage for its approach.

Which one needs a loading dose?

Emgality: 240 mg to start, as two 120 mg injections, then 120 mg monthly. Aimovig starts directly at 70 mg monthly.

Are they interchangeable?

They are separate products with separate labels, trials and mechanisms. Whether one can substitute for the other in any person's treatment is a prescribing question this page does not answer.

MigraineTwo labels compared

Aimovig vs Emgality

Aimovig and Emgality are both monthly injections for the preventive treatment of migraine, and they attack opposite ends of the same signal: Aimovig binds the CGRP receptor, Emgality binds the CGRP molecule. One human antibody, one humanized; one with a loading dose, one without; and one of them also covers cluster headache. This page compares the two labels.

Aimovig

Ingredient: Erenumab
Approved for: Preventive treatment of migrainecovers migraine
Supply: Prescription
Boxed warning: None
Pharmacy cost: $753.41 per milliliter, brandwhat pharmacies pay to buy it, not the price at the counter

Amgen, Inc. Label version 25, effective 14 July 2026.

Emgality

Ingredient: Galcanezumab
Approved for: Preventive treatment of migraine, and episodic cluster headachecovers migraine
Supply: Prescription
Boxed warning: None
Pharmacy cost: $734.41 per milliliter, brandwhat pharmacies pay to buy it, not the price at the counter

Eli Lilly and Company. Label version 17, effective 5 June 2026.

01From the FDA label

Side by side, straight from the labels

Generated from the two source labels, not typed out by hand, so it cannot drift from what the regulator approved. Rows where both labels say exactly the same thing are marked.

Label section	AimovigErenumab	EmgalityGalcanezumab
Active ingredient	AimovigErenumabCGRP receptor antibody	EmgalityGalcanezumabCGRP ligand antibody
Approved for	AimovigPreventive treatment of migraine	EmgalityPreventive treatment of migraine, and episodic cluster headache
Supplysame in both	AimovigPrescription	EmgalityPrescription
What pharmacies payAcquisition cost, not retail	Aimovig$753.41 per milliliter, brand	Emgality$734.41 per milliliter, brand
Boxed warningsame in both	AimovigNone	EmgalityNone
What the FDA approved it for	Aimovig AIMOVIG is indicated for the preventive treatment of migraine in adults. AIMOVIG is a calcitonin gene-related peptide receptor antagonist indicated for the preventive treatment of migraine in adults.	Emgality EMGALITY ® is a calcitonin-gene related peptide antagonist indicated in adults for the: preventive treatment of migraine. treatment of episodic cluster headache.
Forms and strengths	Aimovig AIMOVIG is a sterile, clear to opalescent, colorless to light yellow solution available as follows: Injection: 70 mg/mL in a single-dose prefilled SureClick ® autoinjector Injection: 140 mg/mL in a single-dose prefilled SureClick ® autoinjector Injection: 70 mg/mL in a single-dose prefilled syringe Injection: 140 mg/mL in a single-dose prefilled syringe Injection: 70 mg/mL solution in a single-dose prefilled SureClick ® autoinjector Injection: 70 mg/mL solution in a single-dose prefilled syringe Injection: 140 mg/mL solution in a single-dose prefilled syringe	Emgality EMGALITY is a sterile clear to opalescent, colorless to slightly yellow to slightly brown solution available as follows: Injection: 120 mg/mL in a single-dose prefilled pen Injection: 120 mg/mL in a single-dose prefilled syringe Injection: 100 mg/mL in a single-dose prefilled syringe Injection: 120 mg/mL solution in a single-dose prefilled pen Injection: 120 mg/mL solution in a single-dose prefilled syringe Injection: 100 mg/mL solution in a single-dose prefilled syringe
How the label says it is taken	Aimovig For subcutaneous use only Recommended dosage is 70 mg once monthly; some patients may benefit from a dosage of 140 mg once monthly Administer in the abdomen, thigh, or upper arm subcutaneously See Dosage and Administration for important administration instructions	Emgality For subcutaneous use only. Migraine recommended dosage: 240 mg loading dose (administered as two consecutive injections of 120 mg each), followed by monthly doses of 120 mg. Episodic cluster headache recommended dosage: 300 mg (administered as three consecutive injections of 100 mg each) at the onset of the cluster period, and then monthly until the end of the cluster period. Administer in the abdomen, thigh, back of the upper arm, or buttocks subcutaneously.
Most common adverse reactions	Aimovig most common adverse reactions in AIMOVIG clinical studies (occurring in at least 3% of treated patients and more often than placebo) are injection site reactions and constipation. most common adverse reactions (incidence ≥ 3% and more often than placebo) in the migraine studies were injection site reactions and constipation.	Emgality most common adverse reactions (incidence ≥2% and at least 2% greater than placebo) in EMGALITY clinical studies were injection site reactions. most common adverse reaction was injection site reactions. In Studies 1, 2, and 3, 1.8% of patients discontinued double-blind treatment because of adverse events.
Warnings and precautions	Aimovig Hypersensitivity Reactions: If a serious hypersensitivity reaction occurs, discontinue administration of AIMOVIG and initiate appropriate therapy. Hypersensitivity reactions can occur within hours to more than one week after administration. Constipation with Serious Complications: Serious complications of constipation may occur. Hypertension: New-onset or worsening of pre-existing hypertension may occur. Raynaud's Phenomenon: New-onset or worsening of pre-existing Raynaud's phenomenon may occur.	Emgality Hypersensitivity Reactions: If a serious hypersensitivity reaction occurs, discontinue administration of EMGALITY and initiate appropriate therapy. Hypersensitivity reactions can occur days after administration, and may be prolonged. Constipation with Serious Complications: Serious complications of constipation may occur. Hypertension: New-onset or worsening of pre-existing hypertension may occur. Raynaud's Phenomenon: New-onset or worsening of pre-existing Raynaud's phenomenon may occur.
Contraindications	Aimovig AIMOVIG is contraindicated in patients with serious hypersensitivity to erenumab-aooe or to any of the excipients. Reactions have included anaphylaxis and angioedema.	Emgality EMGALITY is contraindicated in patients with serious hypersensitivity to galcanezumab-gnlm or to any of the excipients.
Label version	Aimovig14 July 2026	Emgality5 June 2026

02Written by us

Opposite ends of one signal

The Aimovig label describes a human monoclonal antibody that binds to the CGRP receptor and antagonizes its function. The Emgality label describes a humanized monoclonal antibody that binds the CGRP ligand and blocks it from reaching that receptor. The signal being interrupted is the same; the point of interruption is not.

03Written by us

Dosing: straight in against loading first

Aimovig starts at its maintenance dose: 70 mg once monthly, with a note that some patients may benefit from 140 mg. Emgality begins with a 240 mg loading dose - two consecutive 120 mg injections - then 120 mg monthly. Both are for subcutaneous use only, in the abdomen, thigh or upper arm.

04Written by us

One indication against two

Aimovig's label covers the preventive treatment of migraine in adults, full stop. Emgality's adds treatment of episodic cluster headache with its own separate regimen. Neither label carries a boxed warning, and neither treats an attack in progress.

05Written by us

What this page does not tell you

It does not say whether binding the receptor or the ligand is better - the labels themselves make no such comparison, and the two products were approved on separate trials. That question, like the choice of any preventive treatment, belongs to a clinician.

06Written by us

Common questions

What is the practical difference between binding the receptor and the ligand?: The labels state the mechanisms without ranking them: Aimovig antagonizes the CGRP receptor, Emgality intercepts the CGRP molecule before it reaches the receptor. Neither document claims an advantage for its approach.
Which one needs a loading dose?: Emgality: 240 mg to start, as two 120 mg injections, then 120 mg monthly. Aimovig starts directly at 70 mg monthly.
Are they interchangeable?: They are separate products with separate labels, trials and mechanisms. Whether one can substitute for the other in any person's treatment is a prescribing question this page does not answer.

Sources

Every fact above comes from one of these documents. The date is the effective date of the label version this page was built from.

FDA prescribing information for Aimovig
Amgen, Inc. Label version 25, effective 14 July 2026.
Full label on DailyMed Approval record BLA761077
FDA prescribing information for Emgality
Eli Lilly and Company. Label version 17, effective 5 June 2026.
Full label on DailyMed Approval record BLA761063

Each stripe is one section of the label, each division in a stripe one entry in that section.

Other comparisons in this category

Page last updated 29 August 2026

Compiled by the HealthyStudy editorial team from FDA source documents. No medical reviewer is credited on this page, because none reviewed it.