The lender said it was making the move as it sought to innovate and expand the market to help advisers give customers good outcomes.
Loans are available from £7,500 to a maximum of £100,000 inclusive of fees, with a full valuation required on each case.
The minimum valuation is £85,000 and loan terms are available from three years to 30 years.
The new offering is available on Optimum’s variable rate loan and fixed rate loans from two to five years.
Optimum Credit commercial director Simon Mules said: “This is a high-quality product for borrowers with a track record of sound financial management, and we have a robust affordability assessment to ensure that our customers have the means to repay their loans without difficulty.
“We have an unrivalled track record in originating prime second charge mortgages, and we have the full backing of our funders in the launch of this new product.”