Tier 1 and Tier 2 drugs are the lowest-cost categories on your health insurance formulary, which is the list of medications your plan agrees to cover. Tier 1 almost always means generic drugs with the smallest copayment, often under $10 for a 30-day supply. Tier 2 typically includes preferred brand-name drugs or sometimes higher-cost generics, with moderately higher copays. The distinction matters because a drug’s tier assignment directly determines what you pay at the pharmacy counter, and those costs shape whether people actually take their medications consistently.
How Formulary Tiers Work
A formulary is essentially a menu of covered drugs organized into cost-sharing levels. Most insurance plans today use between three and six tiers, with Tier 1 at the bottom (cheapest for you) and higher tiers costing progressively more. The system did not always work this way. Plans historically used simpler structures, but over time shifted to multi-tier designs that sort drugs by cost and therapeutic value. Research tracking this evolution found plans moving from one-tier or two-tier formularies to three-tier structures, with each added tier creating a new cost-sharing level for enrollees.1PubMed. The effect of incentive-based formularies on prescription-drug utilization and spending
Tier 1 drugs are the workhorses of any formulary. They are overwhelmingly generics, and they carry the lowest out-of-pocket cost. In Medicare Part D plans, Tiers 1 and 2 typically cover generics with an average copayment below $10.2Schaeffer Center White Paper Series. What Are Tier 1 and Tier 2 Drugs? Coverage and Costs Tier 2 sits just above, usually covering preferred brand-name medications or generics that cost slightly more to produce or distribute. The jump from Tier 1 to Tier 2 might mean a copay of $15 to $40 instead of $5 to $10, though every plan sets its own numbers.
Beyond Tier 2, the landscape shifts. Tier 3 commonly holds non-preferred brand-name drugs, with copays that can reach $60 to $100 or more. Tier 4 is often reserved for specialty medications that treat complex conditions and can cost hundreds per fill. Some plans add a Tier 5 for the most expensive specialty drugs, where you might owe a percentage of the drug’s price (coinsurance) rather than a flat copay. The practical effect is that a drug on Tier 1 could cost you $5 a month, while the same therapeutic class of medication on Tier 4 might cost $200 or more.
What Decides Which Tier a Drug Lands On
Drug tier placement is not random. Insurers and their pharmacy benefit managers (PBMs) evaluate medications based on clinical effectiveness, safety, and cost. A committee of pharmacists and physicians reviews available evidence and decides which drugs within a therapeutic class deserve preferred status. When two drugs treat the same condition equally well, the cheaper one (or the one whose manufacturer offers a larger rebate) gets the lower tier.
Rebates play a larger role than most people realize. Drug manufacturers compete to have their branded products placed on lower, more favorable tiers by offering financial rebates to PBMs. Research examining how PBMs use tier placement as a negotiating tool found that the ability to move branded drugs between preferred and non-preferred tiers substantially increases the rebate payments manufacturers are willing to offer.3Econometrica. Fisher–Schultz Lecture: Contracting Over Pharmaceutical Formularies and Rebates In plain terms, the threat of putting a drug on a higher tier (where fewer patients will use it because of cost) gives PBMs leverage to negotiate lower net prices. That is good for the plan’s overall spending, though the savings do not always flow directly to you at the pharmacy counter.
Generic availability is the single biggest factor pushing a drug to Tier 1. An analysis of Medicare Part D found that in 2019, about 84 percent of plan-product combinations provided generic-only coverage, meaning the brand-name version was not covered at all once a generic existed.4Health Affairs. Medicare Part D Plans Rarely Cover Brand-Name Drugs When Generics Are Available For the small share of products where a brand was still covered alongside its generic, prices for both tended to be low. The bottom line is that once a drug goes generic, it almost always lands on Tier 1 or Tier 2 and stays there.
Medicare Advantage Plans Versus Standalone Drug Plans
If you are comparing Medicare options, the plan type you choose can affect which drugs sit on the lowest tiers. Medicare Advantage Prescription Drug plans (MA-PDs) commonly cover a larger number of drugs on Tiers 1 and 2 compared to standalone Prescription Drug Plans (PDPs).2Schaeffer Center White Paper Series. What Are Tier 1 and Tier 2 Drugs? Coverage and Costs In some cases, a drug that has a generic available and sits on Tier 1 or 2 in an MA-PD may be covered only as a branded product on Tier 3 by a PDP, leading to higher potential out-of-pocket costs for the PDP enrollee.
This difference is worth paying attention to during open enrollment. Two plans might both “cover” the same medication, but one charges you $8 because it places the generic on Tier 1, while the other charges $45 because it lists the brand on Tier 3. Checking the specific formulary for each plan you are considering, rather than relying on general coverage descriptions, is one of the most practical things you can do to manage prescription costs.
Not All Generics Cost the Same
People tend to think of generics as a single category, but there are meaningful cost differences even within Tier 1. Authorized generics (AGs) are produced by or licensed from the original brand-name manufacturer, while independent generics (IGs) come from separate companies that developed their own formulations after the brand’s patent expired. Both are FDA-approved and therapeutically equivalent, but they do not always cost the same.
A study of Medicare beneficiaries from 2012 to 2020 found that authorized generics consistently cost more out of pocket than independent generics. The median cost per 30-day supply was about $3.19 for authorized generics compared to roughly $2 for independent generics. After adjusting for other factors, independent generics ran about $6.49 less per 30-day supply on average.5PubMed Central. Analysis of the Utilization and Out-of-Pocket Costs of Authorized Generics and Independent Generics Among Medicare Beneficiaries These differences are small per fill, but over a year of monthly prescriptions for multiple medications, they add up. If your pharmacy offers a choice, asking whether an independent generic is available could shave dollars off your annual drug spending.
Why Your Tier Assignment Affects More Than Your Wallet
Tier placement is not just a billing detail. The copay you face at the pharmacy shapes whether you fill the prescription at all, whether you refill it consistently, and ultimately whether the medication does its job. A large systematic review covering multiple disease areas found that higher cost-sharing was consistently associated with worse medication adherence, and the bigger the cost-sharing increase, the worse the adherence got.6PubMed Central. Cost-sharing and adherence, clinical outcomes, health care utilization, and costs: A systematic literature review People do not necessarily make a conscious decision to stop taking a medication. They skip a refill because the copay is tight that month, then another, and gradually drift away from treatment.
This means that a drug’s tier assignment has downstream health consequences. A medication on Tier 1 at $5 a month is far more likely to be taken consistently than the same medication on Tier 3 at $60. For chronic conditions like diabetes, heart disease, or depression, where steady medication use is the whole point, higher copays translate into more emergency room visits, more hospitalizations, and worse long-term outcomes. The relationship is not subtle; it shows up across nearly every disease area that researchers have examined.
Utilization Management on Top of Tiers
Even when a drug is on a covered tier, you may still face hurdles before your plan pays its share. Insurers layer utilization management tools on top of the tier system to control spending and steer patients toward lower-cost alternatives. The most common tools are prior authorization, step therapy, and quantity limits.
Prior authorization requires your doctor to get approval from the insurer before the prescription is filled. The insurer wants documentation that the drug is medically necessary for your condition. Step therapy, sometimes called “fail first,” takes this further: you must try and fail on certain lower-cost medications before the insurer will cover a more expensive drug for the same condition.7PubMed Central. What Are Tier 1 and Tier 2 Drugs? Coverage and Costs – Section: Step Therapy: “Fail-First” Protocols In practice, this often means starting on a Tier 1 generic and working your way up through the tiers only if cheaper options do not work or cause unacceptable side effects.
These requirements are generally applied to drugs on higher tiers, so Tier 1 medications rarely have utilization management barriers. That is another practical advantage of being on the lowest tier: not only is the copay small, but the prescription goes through without delays or paperwork. If your doctor prescribes something on Tier 3 or above, expect the possibility of prior authorization or a step therapy requirement, and be prepared for the process to take days or sometimes weeks.
When Your Drug Changes Tiers Mid-Year
A common and frustrating experience is going to the pharmacy and finding that a medication you have been filling for months now costs more because your plan moved it to a higher tier. Plans can change their formulary during the year, and the rules allow more flexibility than most people expect. Under Medicare Part D, for example, a plan can make formulary changes as long as it notifies the Centers for Medicare and Medicaid Services (CMS) and all affected beneficiaries 60 days before the change takes effect. The plan may post the notice on its website, though most also send letters to affected enrollees. If CMS does not disapprove the change within 30 days of the notice, approval is automatic.8Drug Topics. Formulary changes and transition policies
If your medication gets moved to a higher tier or removed from the formulary entirely, you have a few options. You can ask your doctor to submit an exception request arguing that the drug is medically necessary for you. You can switch to whatever alternative the plan now prefers on a lower tier. Or, during the next open enrollment period, you can switch to a plan that still covers your medication favorably. The key is paying attention to those notices rather than ignoring them, since the 60-day window is your heads-up to plan ahead.
Value-Based Insurance Design
A growing approach to formulary design flips the usual logic. Instead of assigning tiers purely by drug cost, value-based insurance design (VBID) sets copays based on how much clinical benefit a medication delivers. The idea is straightforward: the more valuable a therapy is for a patient’s health, the lower the copay should be, even if the drug itself is expensive.9PubMed Central. A controlled trial of value-based insurance design – the MHealthy: Focus on Diabetes (FOD) trial
Real-world experiments with VBID have shown promising results. When the corporation Pitney Bowes eliminated copayments for cholesterol-lowering statins and reduced copays for the blood-clot inhibitor clopidogrel, statin adherence jumped nearly 3 percent immediately compared to a control group and held steady over the following year. For clopidogrel, the reduced copay stabilized adherence that had been declining, producing a four-percentage-point gap between the intervention group and controls after a year.10PubMed. At Pitney Bowes, value-based insurance design cut copayments and increased drug adherence Those percentage points translate into fewer heart attacks and strokes, which in turn reduce the plan’s spending on hospitalizations.
VBID has gained traction in Medicare as well, with CMS running demonstration programs that allow participating plans to reduce cost-sharing for high-value services. The concept essentially argues that Tier 1 should not just mean “cheapest drug” but “drug that delivers the most health for the dollar.” Whether that principle gets widely adopted remains an open question, but the early evidence suggests it improves outcomes without increasing overall costs.
State Laws That Cap What You Pay
Several states have passed laws capping out-of-pocket spending on certain drug categories, and these caps interact with the tier system in important ways. The most prominent examples involve insulin and specialty drugs, where even a Tier 2 or Tier 3 copay can be financially devastating for patients who need the medication indefinitely.
A study of state insulin copayment caps found that for basal insulins, the policy was associated with a roughly 33 percent drop in mean monthly out-of-pocket spending per prescription. Adherence to bolus insulins improved by about 3.3 percentage points, representing a 5 percent increase. The researchers noted that improvements in health outcomes depended on how the cap level was set, meaning caps that are too generous relative to existing copays may not change behavior, while tighter caps produce measurable gains.11JAMA Network Open. Health Outcome Changes in Individuals With Type 1 Diabetes After a State-Level Insulin Copayment Cap
For specialty drugs more broadly, state caps have shown even larger dollar-amount effects among the highest spenders. One analysis found that caps were associated with a reduction of about $351 per month for specialty-drug users at the 95th percentile of spending, a 32 percent cut.12PubMed. Patient and Plan Spending after State Specialty-Drug Out-of-Pocket Spending Caps These laws effectively override the tier system for targeted drug categories, guaranteeing that your copay will not exceed a set amount regardless of which tier the plan assigns the drug to. If you take an expensive chronic medication, checking whether your state has enacted a relevant cap is worth the effort.
How the United States Compares
The tiered formulary system is largely an American phenomenon, born from a healthcare structure that relies heavily on private insurance and market-based drug pricing. In many other countries, governments negotiate drug prices directly and set uniform cost-sharing rules. A comparison of pharmaceutical access between the US and the UK found that cost-sharing in the US was significantly higher than in the UK, with much wider variation across plans.13PubMed. Comparing patient access to pharmaceuticals in the UK and US In the UK’s National Health Service, prescription charges are a flat rate per item (or free entirely for many patient groups), with no tier system to navigate.
This does not mean every aspect of the US system is worse. The multi-tier approach, for all its complexity, does create competitive pressure among drug manufacturers through rebate negotiations, which can lower net prices for plans. And the US formulary system generally provides faster access to newly approved drugs than systems that require centralized cost-effectiveness evaluations before coverage decisions. But the tradeoff is that individual patients bear more of the cost burden and face considerably more complexity in figuring out what they owe.
Practical Steps for Managing Your Tier Costs
Understanding tiers is useful, but knowing how to work within the system is more useful still. A few strategies can meaningfully reduce what you pay.
- Check the formulary before choosing a plan: During open enrollment, look up your specific medications on each plan’s drug list. A plan with a lower monthly premium might place your drugs on higher tiers, costing you more overall.
- Ask about therapeutic alternatives: If your medication is on Tier 3 or higher, ask your doctor whether a Tier 1 or Tier 2 drug in the same class would work for your condition. Often there is a cheaper option that is clinically equivalent.
- Request a tier exception: If your doctor believes you need a specific higher-tier drug, they can file an exception request with your insurer. Approval is not guaranteed, but insurers are required to have an exception process, and medical necessity arguments do succeed.
- Use mail-order pharmacies: Many plans offer lower copays for 90-day supplies through mail-order, which can reduce per-month costs for chronic medications.
- Watch for mid-year changes: Read those formulary change notices. If your drug is moving up a tier, you have time to talk to your doctor about alternatives or plan for the cost increase.
The tier system is designed to steer you toward cheaper drugs, and honestly, that steering works in your favor most of the time. Tier 1 generics are clinically equivalent to their brand-name counterparts for the vast majority of conditions. Where the system fails is when it places a drug you genuinely need on a high tier with no adequate lower-tier alternative, forcing you into a cost-versus-health tradeoff that no formulary committee intended but that real patients face every day.