How Does Medicare Cover Insulin and What Is the $35 Cap?

Medicare covers insulin in two different ways depending on how it is delivered. Part B covers insulin when it is used in certain durable medical equipment (DME) insulin pumps that meet Medicare's coverage criteria. In this case, the insulin is treated as a DME supply and billed under Part B rather than Part D.

Part D covers most other insulin — including insulin used with injection pens, syringes, inhaled insulin, and insulin used with non-DME pumps. If you use insulin by injection or with a device that does not qualify as DME under Medicare's rules, your coverage will almost certainly come through your Part D plan.

Under current federal law, your out-of-pocket cost for a covered insulin product is capped at $35 for a one-month supply — under both Part B and Part D. This cap applies even if you haven't met your Part D deductible. The deductible does not apply to insulin.

For a three-month supply, the cap is generally $105 total for each covered insulin. The $35 limit applies per insulin product, not per prescription, so if you use more than one type of insulin, the cap applies to each one separately.

The type of pump or delivery device you use affects which part of Medicare covers your insulin. Traditional external insulin pumps that qualify as DME are covered under Part B — and the insulin used in those pumps is also covered under Part B at the $35 cap. However, the pump device itself is subject to its own coverage rules and cost-sharing.

Insulin patch pumps, disposable pumps, and some newer delivery devices are treated as supplies under Part D rather than DME under Part B. In these cases, the insulin is covered under Part D with the $35 cap, but the device or supply may have separate cost-sharing. Understanding how your specific delivery method is classified under Medicare matters for knowing what you'll actually pay.

The $35 cap only applies to insulin products that are on your plan's formulary. If your specific insulin is not included in your Part D plan's drug list, you won't have access to the capped price through that plan. This is one reason why reviewing your plan's formulary each year — particularly during Annual Enrollment — is so important.

We help our clients review how their insulin is delivered, confirm that their Part D or Medicare Advantage plan covers the right products, and make sure they're getting access to the $35 cap they're entitled to. If you manage diabetes and take insulin, this is a conversation worth having before your next enrollment period.