Many people assume that if two medications have the same name, they must be identical.
In reality, medications with the same active ingredient can contain different inactive ingredients, depending on the manufacturer, dosage form, or formulation.
This difference is often invisible to patients — until something changes.
The Active Ingredient Is the Same — by Law
For FDA-approved medications, brand-name and generic versions must contain:
- The same active ingredient
- The same strength
- The same dosage form
- The same route of administration
This ensures the medication treats the condition in the same way.
For example, all aspirin products contain acetylsalicylic acid as the active ingredient.
Where Differences Begin: Inactive Ingredients
Inactive ingredients (also called excipients) are added to medications for reasons such as:
- Holding tablets together
- Improving stability or shelf life
- Controlling how the medication dissolves
- Adding color or coating
- Forming capsules or liquids
These ingredients do not treat symptoms, but they can differ widely between products.
Why Inactive Ingredients Vary
Inactive ingredients may change due to:
Different Manufacturers
Each manufacturer can choose its own formulation, as long as FDA requirements are met.
Two generic versions of the same medication may be chemically identical in effect — but made with different fillers, binders, or coatings.
Dosage Form Differences
A medication may be available as:
- Tablet
- Capsule
- Delayed-release tablet
- Chewable
- Liquid
- Injection
Each form requires different inactive ingredients to function properly.
Supply Chain Changes
Manufacturers may change inactive ingredient sources over time due to:
- Availability
- Cost
- Manufacturing updates
- Regulatory changes
This can happen without changing the medication name.
Why This Matters to Patients
Most people never notice inactive ingredients — until they do.
Differences in inactive ingredients may explain why:
- A refill looks different than before
- A medication suddenly causes discomfort
- One generic works better for you than another
- A medication previously tolerated becomes problematic
This is especially relevant for people sensitive to certain fillers, dyes, or capsule materials.
Example: Aspirin Is Not Always “Just Aspirin”
Aspirin products may contain inactive ingredients such as:
- Corn starch
- Lactose
- Dyes
- Cellulose
- Coatings or polish agents
Two aspirin tablets with the same strength can have very different ingredient lists, even though the active ingredient is identical.
Why Pharmacies May Switch Products
Pharmacies may dispense different manufacturers’ products based on:
- Availability
- Insurance contracts
- Cost
- Supply shortages
Unless specifically requested, the manufacturer may change between refills.
How to Check What’s Actually in Your Medication
The most reliable way to understand what you’re taking is to review the ingredient list for that specific product — not just the medication name.
PillParser helps by:
- Displaying active and inactive ingredients from medication labels
- Organizing ingredient information clearly
- Linking to educational pages that explain what common ingredients are and why they’re used
This allows you to research ingredients in one place instead of searching multiple sources.
What PillParser Does — and Does Not Do
PillParser:
- Shows ingredient lists as published in labeling sources
- Helps organize and explain ingredient terminology
- Provides educational reference information
PillParser does not:
- Make medical recommendations
- Judge safety or suitability
- Replace advice from a pharmacist or healthcare professional
Key Takeaway
Medications with the same name can be chemically equivalent — but not always compositionally identical.
Understanding inactive ingredients helps explain why medications may differ from one manufacturer to another and why paying attention to ingredient lists matters.
To keep PillParser free, anonymous scans are limited.
Educational Note
This page is provided for educational purposes only and does not make medical claims. Always confirm medication details with a pharmacist or healthcare professional.