We train hard in the gym to gain muscle, strength, speed, endurance, and whatever else have you. But for anyone that spends countless hours in the gym, losing your gains can be detrimental.

Whether you’re off the gym for a few weeks or you’re training in a fasted state, we do whatever is necessary to protect ourselves against muscle loss.

While a solid nutrition plan and good lifestyle habits can help safeguard you against muscle degradation, a well-thought-out supplement plan can, too. And of all the options you have, HMB is one that needs to be on the top of the list.

HMB is a leucine metabolite that is known to protect against muscle loss, but what happens when you pair it with one of the most well-known vitamins out there—vitamin D?

We’re here to give you everything you need to know about the benefits of supplementing with HMB and why it may be wise to throw in some of the sunshine vitamin.

What You Need To Know About HMB

Where performance supplements are concerned, HMB isn’t one that often comes to the forefront—but it should. For anyone looking to enhance overall athleticism, HMB is gold.

Before we can get into the nitty-gritty of HMB, we first have to talk about something most fitness enthusiasts and athletes are familiar with—leucine. Of the amino acids, leucine takes the cake for being the most anabolic.

Of the three branched-chain amino acids, leucine exhibits the highest oxidation rates, which is the primary reason why it’s so thoroughly investigated.

Studies show that consuming BCAAs with a minimum of 30-35% leucine before or during endurance exercise may help to reduce the net rate of protein degradation, improve mental and physical performance, and may exhibit glycogen sparing effect to prevent muscle glycogen degradation and depletion of muscle glycogen stores 1.

All of these equates to better muscle growth and preservation and drastically reduces the chance of muscle loss. So, there’s no denying that leucine offers quite the list of benefits for athletes, but what does it have to do with HMB?

It’s been suggested that the anti-catabolic effects of leucine may be attributed to a specific compound called beta-hydroxy-beta-methylbutyrate, more commonly known as HMB, that is a metabolic by-product of leucine breakdown.

When leucine is metabolized, roughly 80% is shunted towards muscle protein synthesis (that’s why we love leucine), while the remaining 20% is divided up between two metabolites: alpha-ketoisocaproate (a-KIC) and HMB.

Leucine breakdown yields about 15% a-KIC and out 5% HMB 2. However, while the metabolite may only make up a small proportion of leucine breakdown, the effects it has on performance and recovery are anything but small.

Benefits of HMB

For anyone that trains in a fasted state, HMB may be your key to preserving muscle gains. HMB has been shown to exert powerful effects on increasing lean body mass and strength during exercise. This is based on two proposed mechanisms 3:

  1. HMB may slow or suppress muscle proteolysis that increases during exercise.
  2. HMB is a precursor of muscle-cell cholesterol; increases in muscle hypertrophy during resistance training may result in a local deficiency in cholesterol in muscle cells, which leads to insufficient amounts of cholesterol for membrane synthesis and, therefore, slower cell growth or suboptimal function of cell membranes due to low levels of membrane cholesterol. Increasing amounts of cholesterol in muscle would theoretically allow the muscle to maintain and synthesize new muscle plasma membranes.

Although HMB exhibits powerful effects on muscle preservation for people in a fasted state (or any other catabolic state), it can also offer major benefits for everyone else.

On top of the mechanisms that we just mentioned, the anti-catabolic effects of HMB are also because of its ability to stimulate muscle protein synthesis via increasing the mTOR and phosphorylation of p70S6K 4.

What’s more, it’s also postulated to stimulate MPS through the growth hormone/IGF‐1 axis, which promotes positive effects for resistance-trained athletes: improvements in strength, body fat levels, and muscle mass, along with better anaerobic performance and power output 5, 6.

Vitamin D For Athletic Performance

On the other end of the spectrum, we have one of the most popular—but also the most deficient—nutritional supplements around, vitamin D. Of the many roles vitamin D plays in maintaining health, its role in bone metabolism and immune function often top the charts. But where vitamin D is concerned, there’s more.

Most people aren’t aware that sufficient vitamin D levels are actually needed to maintain optimal athletic performance. That’s because it plays critical roles in immune function and the inflammatory response, protein synthesis, muscle function, cardiovascular function, cell growth, and musculoskeletal regulation 7.

Studies consistently show links between low vitamin D status and poor athletic outcomes, but boosting levels through supplementation can improve muscle strength, reduce rates of injury, and better sports performance.


Vitamin D exerts its actions through two pathways: endocrine and autocrine functions 6, 7.

The endocrine mechanism is responsible for what we typically know vitamin D for—bone metabolism via calcium regulation. Vitamin D promotes calcium uptake from the gut and enhances osteoclastic activity, thereby supporting bone growth, bone mineral density, and bone remodeling.

When vitamin D concentrations fall below the normal threshold, parathyroid hormone (PTH) increases bone resorption to meet the body’s demand for calcium.

As a result, bone turnover increases along with the risk of bone injury. For athletes or anyone participating in sports with high physical demand, this can be a significant red zone.

The other pathway vitamin D walks is the autocrine pathway. It is essential for a number of vital metabolic processes, some of which include 7:

  • Signaling processes
  • Expression and genetic response
  • Hormone protein synthesis
  • Immune function and inflammatory response
  • Cell synthesis

While vitamin D has powerful health benefits on its own, it also serves a unique role when combined with HMB.

HMB And Vitamin D: What’s The Connection?

Pairing other vitamins has the potential to enhance their biological activities. For example, vitamin D is needed to support the role of calcium in bone health; vitamin C can help regenerate vitamin E to support antioxidant activity.

But where HMB is concerned, adding in the sunshine vitamin may brighten up its role in muscle growth and preservation.

There’s no denying that HMB offers some great benefits for muscle mass, strength, function, and protein kinetics, but the extent of those benefits may be dependent on circulating levels of vitamin D 8.

Here’s some of the research to prove it.

  • A 2020 study published in the Journal of Gerontology Medicine Sciences looked at the effect of HMB supplementation combined with vitamin D on muscle strength in adults over 60 with low vitamin D status 9. Results found HMB+D3 supplementation offered significant benefits for lean body mass in the non-exercise group at six months. They concluded that HMB+D3 supplementation may enhance muscle strength and physical functionality in older adults regardless of exercise regimens.
  • A 2016 study published in Nutrition in Clinical Practice investigated the effects of calcium, HMB, vitamin D, and protein supplementation on wound healing, immobilization period, muscle strength, and laboratory parameters in older adults with hip fractures 10. Researchers found that the combination accelerated wound healing, reduced immobilization period, and increased muscle strength without altering BMI.

However, it is important to note that most studies about HMB+D3 are conducted in older populations, so results may differ.

Regardless, evidence shows a connection between HMB and D3, so it may be wise to take them together.

Where To Find HMB+D3

It’s easy enough to get your hands on HMB and vitamin D3 supplements alone, but why not take them in two killer supplements to elevate your performance to new heights?

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Pre Lab Pro® uses a combination of five powerful ingredients + NutriGenesis vitamins and minerals to help you shatter your limits. It’s designed to reach beyond strength and stamina to unleash your inner beast most.

Sparking a 2X muscle-pumping nitric oxide (NOx) turbocharge + afterburn, Pre Lab Pro® helps you crush your workout with an exhilarating blood flow boost to provide physical and mental energy, peak muscle power and efficiency, and extended endurance with laser intensity and calm clarity.

When you stack it with Burn Lab Pro®, you’re also getting fat burn and muscle growth to the extreme. Burn Lab Pro® also stacks five power-packed ingredients—including HMB—to ignite your metabolic fire and torch calories, build muscle, and burn fat.

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  3. E Jówko, P Ostaszewski, M Jank, et al. Creatine and beta-hydroxy-beta-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program. 2001;17(7-8):558-566.
  4. JM Wilson, PJ Fitschen, B Campbell, et al. International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB). J Int Soc Sports Nutr. 2013;10(1):6.
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  7. M de la Puente Yagüe, L Collado Yurrita, MJ Ciudad Cabañas, MA Cuadrado Cenzual. Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends.  2020;12(2):579.
  8. JC Fuller Jr, S Baier, P Flakoll, SL Nissen, NN Abumrad, JA Vitamin D status affects strength gains in older adults supplemented with a combination of β-hydroxy-β-methylbutyrate, arginine, and lysine: a cohort study.JPEN J Parenter Enteral Nutr. 2011;35(6):757-762.
  9. JA Rathmacher, LM Pitchford, P Khoo, et al. Long-term Effects of Calcium β-Hydroxy-β-Methylbutyrate and Vitamin D3 Supplementation on Muscular Function in Older Adults With and Without Resistance Training: A Randomized, Double-blind, Controlled Study.J Gerontol A Biol Sci Med Sci. 2020;75(11):2089-2097.
  10. O Ekinci, S Yanık, B Terzioğlu Bebitoğlu, E Yılmaz Akyüz, A Dokuyucu, S Erdem. Effect of Calcium β-Hydroxy-β-Methylbutyrate (CaHMB), Vitamin D, and Protein Supplementation on Postoperative Immobilization in Malnourished Older Adult Patients With Hip Fracture: A Randomized Controlled Study.Nutr Clin Pract. 2016;31(6):829-835.