(Reuters) -UnitedHealth's pharmacy benefit manager unit said on Thursday it was adding eight insulin products to its reimbursement list that would limit out-of-pocket spend to $35 or less.

The unit, Optum Rx, will move eight products, including all short- and rapid-acting insulin, to tier one, or preferred status, which offers the lowest price for consumers and is effective Jan. 1.

Eli Lilly, Novo Nordisk and Sanofi will have their insulin products added to the preferred status.

The companies, which together control 90% of the U.S. insulin market, earlier this year pledged to lower the list prices of many of their insulin products by 70%-78% later this year or in 2024.

The Biden administration and some lawmakers have continued to press insulin makers as well as pharmacy benefit managers to lower high prices of the life-saving drug.

Pharmacy benefit managers act as middlemen and negotiate rebates and fees with drug manufacturers, create lists of medications that are covered by insurance and reimburse pharmacies for patients' prescriptions.

Americans with insurance typically pay a fraction of the list prices for prescription drugs, but uninsured people sometimes have to pay the full price, forcing some to ration or skip taking their medicine.

(Reporting by Sriparna Roy in Bengaluru; Editing by Anil D'Silva and Shounak Dasgupta)