Natural and artificial flavor. Targeted, specialized nutrition. No. 1 doctor recommended brand. Revigor to help rebuild muscle and strength naturally lost over time. Amino acid metabolite. 13 g protein. 24 vitamins & minerals. Targeted nutrition to help rebuild muscle and strength naturally lost over time. You can lose 8% of your muscle every 10 years after you turn 40. Ensure Muscle Health has Revigor (source of HMB, an amino acid metabolite) and also is an excellent source of protein to help rebuild muscle and strength naturally lost over time. Gluten-free; suitable for lactose intolerance.