3) MRPs PLUS HMBMeal-replacement products (MRPs) allow you to have some flexibility in reaching your daily nutrition goals. Although MRPs include high-quality proteins such as whey and casein, adding two grams of beta-hydroxy beta-methylbutyrate (HMB) to an MRP can help you make greater gains in growth by preventing potential muscle loss. Closely related to BCAAs, as little as 1.5 grams of HMB daily could accentuate mass gains by slowing the muscle breakdown associated with hardcore training sessions. It's a good idea to boost the muscle-building potential of your MRP by adding 1.5 to 2 grams of HMB to the mix. FLEX.