What Is a Formulary?

A formulary is your insurance plan's approved list of prescription drugs. It determines what your insurance will cover and how much you'll pay at the pharmacy.

Tiers: How Drugs Are Categorized

Most formularies organize drugs into tiers. The lower the tier, the less you pay.

• Tier 1: Generic drugs — lowest cost
• Tier 2: Preferred brand-name drugs — moderate cost
• Tier 3: Non-preferred brand-name drugs — higher cost
• Tier 4–5: Specialty drugs — highest cost, often requires prior authorization

Why Your Drug Might Not Be Covered

If your medication isn't on the formulary, your insurance won't pay for it — you'll pay the full retail price. This happens more than people expect when plans change or during open enrollment transitions.

What You Can Do

• Ask for a generic: If a brand drug isn't covered, a generic version often is
• Request a formulary exception: Your doctor can write a letter of medical necessity asking the insurer to cover a non-formulary drug
• Use a discount card: GoodRx, Cost Plus Drugs, or similar can sometimes beat your insurance price entirely
• Appeal: If denied, you have the right to appeal the decision

Check the Formulary Before Open Enrollment

If you take regular prescriptions, look up your drugs in each plan's formulary before you pick a plan. What you pay monthly in premiums matters much less than what you'll pay at the pharmacy 12 times a year.