The merchant accounts you will need are called high-risk merchant accounts as banks classify online product sales like vitamins as high risk now. You'll sign up for 2 separate accounts because the banks won't want you to generate a large sales volume in the first 90 days. Having 2 accounts makes that a non-issue. Plus, you'll have to stay below 3% chargebacks which means sometimes you'll have to reach out to customers so they can turn their chargeback into a regular cancel. Staying under 3% chargebacks with 2 merchant accounts and 20 sales a month each account is easy.