NIH-funded study provides hope for aging adults

Age-related muscle loss is inevitable


The year-long randomized, double-blind, placebo-controlled study evaluated the effects of HMB in combination with Vitamin D3 on muscle health in older adults with and without exercise training.


Researchers found HMB and Vitamin D3 improved muscle function in older adults, even without exercise.

HMB boosts muscle health in older adults by both stimulating protein synthesis and reducing muscle breakdown. Higher Vitamin D3 levels are associated with greater strength and superior muscle function, especially in older adults. The study indicated that the proper ratio of HMB and Vitamin D3 can boost effects, helping improve muscle function in an entire generation of people.

The study was supported by a grant from the National Institutes of Health and published in The Journals of Gerontology.

Study Abstract

The primary aim of this study was to determine whether supplementation with calcium β-hydroxy-β-methylbutyrate (HMB) and Vitamin D3 (D) would enhance muscle function and strength in older adults. Older adults over 60 years of age with insufficient circulating 25-hydroxy-Vitamin D (25OH-D) levels were enrolled in a double-blinded controlled 12-month study.

Long-term Effects of Calcium β-Hydroxy-β-methylbutyrate (HMB) and Vitamin D3 Supplementation on Muscular Function in Older Adults with and without Resistance Training: A Randomized, Double-blind, Controlled Study
The Journals of Gerontology

  • John Rathmacher, Ph.D.
    Principal Investigator

    "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.”

  • John Rathmacher, Ph.D.
    Principal Investigator

    "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.”

Study FAQ

What is HMB?

HMB stands for β-hydroxy β-methylbutyrate, which is naturally produced in our bodies during the metabolism of the essential amino acid leucine. Leucine is a part of the food chain – we eat it every day in soybeans, beef, alfalfa, and fish.

How does HMB work?

HMB aids in increasing muscle protein in two ways:

  1. Decreases protein breakdown from hard workouts. HMB disrupts protein breakdown by decreasing the ubiquitin-proteasome proteolytic pathway.
  2. Increases protein synthesis for increased strength. Several studies indicate that HMB stimulates protein synthesis through multiple mechanisms including the mTOR pathway.
How many people participated in the study? What was measured?

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

What were the results?

The results indicated that HMB’s long-term functional benefits are fully realized among older adults when there is sufficient Vitamin D3 present:

  • Among non-exercisers, participants taking HMB+D experienced greater improvements in physical function and tended to have greater increases in strength than did participants taking the placebo supplement, and they sustained this improvement over one year.
  • Exercise was not needed to realize the muscle health benefits of HMB+D. Combining HMB+D and moderate resistance training did not provide any further benefit over either exercise or HMB+D alone. “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,” explains  principal investigator John Rathmacher.
  • HMB+D may also help people feel more energetic. In addition to physical benefits, HMB+D increased ‘high activation’ emotions.
Is consuming additional protein sufficient for maintaining muscle mass?

According to principal investigator John Rathmacher, Ph.D. “It is unrealistic to simply increase dietary protein because as we age, we begin to lose our ability to respond to certain signals such as how our body responds to ingesting protein or to exercise. As a result, we need more protein or exercise to achieve the same muscle growth responses.”

HMB can boost muscle health in older adults, as it uniquely both stimulates protein synthesis and reduces muscle breakdown. And, higher Vitamin D 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 Rathmacher.

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