The combination of HMB (Calcium β-Hydroxy-β-methylbutyrate) and Vitamin D3 has the potential to enhance muscle strength and physical functionality in older adults, even without exercise, according to research published in The Journals of Gerontology. The year-long randomized, double-blind, placebo-controlled study indicates was supported by a grant from the National Institutes of Health (NIH).

A press release from TSI USA, LLC, which produces and markets the branded ingredient myHMB, discussed the science, explaining that HMB stimulates protein synthesis and reduces muscle breakdown, while higher vitamin D3 levels are associated with greater strength and superior muscle function, especially in older adults. “With this study, we now understand HMB and vitamin D3 can have a synergistic effect in older adults, superior to what either can do individually,” said lead researcher John Rathmacher, Ph.D., in the release. Dr. Rathmacher serves as Director of Clinical Research and Laboratory Services at Metabolic Technologies, LLC, the company that discovered HMB and is now owned by TSI.

In the study, 117 healthy adults ages 60 and older were assigned to take HMB + Vitamin D3 or a placebo. Half of the subjects in each group participated in a mild resistance training program consisting of 60-minute supervised progressive resistance training sessions, three days a week; the other half did not exercise. Physical function, muscle strength, and body composition were measured at three-month intervals.

The results, as outlined in the release:



  • Among non-exercisers, participants taking HMB+D experienced greater improvements in physical function and tended to have greater increases in strength compared to participants taking the placebo. Improvements were sustained over one year.
  • Combining HMB+D and moderate resistance training did not provide any further benefit over either exercise or HMB+D alone. Dr. Rathmacher noted: “This indicates that HMB+D may uniquely protect muscle strength and physical function in those who are unable or unwilling to exercise such as older adults who are frail or have age-related muscle loss."

  • HMB+D may help people feel more energetic. “In addition to physical benefits, HMB+D increased ‘high activation’ emotions,” Dr. Rathmacher explained.

Dr. Rathmacher added in the release:  “The most exciting thing about this study is that with HMB+D, there was a significant improvement in muscle function in the non-exercise group specifically. That is very powerful given the percentage of our older adult population who are unable or unwilling to exercise. While the benefits of exercise are much broader than muscle mass or muscle strength, the improvement of physical function is potentially very powerful for the health of this population. I am unaware of any other nutrient capable of doing this.”

TSI also pointed to the broad reach, noting that involuntary age-related muscle loss affects 100% of the population, with muscle mass declining at a rate of about 1% per year after age 70, increasing risk of falls. “We should all be using something to stem the problem of muscle loss, because once we notice it, it may be way too late,” said Larry Kolb, President of TSI, in the release. He added, “There is a large population who either know they need exercise to maintain their muscle mass but don’t do it; or, they don’t do it to a sufficient level to maintain muscle health. Others, especially among the older population, may be too frail or have other limitations prohibiting exercise." 

While HMB generally works best with higher intensity exercise than used in this study, Dr. Rathmacher said, "the likelihood of this age group starting and following such an intensive exercise regimen is in the single digits at best. The number willing to consistently do resistance training to maintain muscle mass is even smaller. HMB may be an incredible alternative.”