MyHMB® (Calcium HMB)
Mechanism of Action +
### Leucine Metabolism and HMB Production Beta-hydroxy beta-methylbutyrate (HMB) is a downstream metabolite of the essential branched-chain amino acid (BCAA) L-leucine. In the human body, leucine is reversibly transaminated to alpha-ketoisocaproate (KIC). While the majority of KIC is metabolized into isovaleryl-CoA in the mitochondria, approximately 5% is oxidized in the cytosol by the enzyme KIC dioxygenase to produce HMB. Because only a tiny fraction of dietary leucine converts to HMB, achieving the clinically effective dose of 3 grams of HMB would require consuming roughly 60 grams of leucine daily—an impractical and potentially gastrointestinally distressing amount. This metabolic bottleneck necessitates direct HMB supplementation to achieve therapeutic intramuscular concentrations.
### Anticatabolic Action: The Ubiquitin-Proteasome System The primary and most well-documented mechanism of HMB is its profound anticatabolic effect. Muscle protein breakdown (MPB) is largely governed by the ubiquitin-proteasome system (UPS) and various caspases. During periods of physiological stress—such as intense resistance training, caloric restriction, illness, or aging (sarcopenia)—the expression of UPS components is upregulated, leading to the tagging and degradation of muscle proteins. HMB directly attenuates the expression and activity of the UPS, effectively putting the brakes on muscle wasting. This makes HMB up to 20 times more potent than leucine on a gram-for-gram basis at preventing muscle breakdown.
### Anabolic Action: mTORc1 Activation While HMB is primarily anticatabolic, it also exerts mild anabolic effects. Like its parent amino acid leucine, HMB stimulates the mammalian target of rapamycin complex 1 (mTORc1). Activation of mTORc1 initiates a cascade of signaling events (including the phosphorylation of p70S6k and 4E-BP1) that upregulate translation initiation, the rate-limiting step in muscle protein synthesis (MPS). However, clinical data indicates that while HMB can stimulate MPS, leucine is significantly more effective at this specific task. Therefore, HMB is best viewed as a muscle preserver rather than a primary muscle builder.
### Sarcolemma Repair: Cholesterol Synthesis Pathway A secondary, yet critical, mechanism of HMB involves its role as a precursor in the synthesis of cholesterol. HMB is converted into beta-hydroxy beta-methylglutaryl-CoA (HMG-CoA), which is a direct precursor for cholesterol synthesis via the mevalonate pathway. Skeletal muscle cells rely on localized cholesterol synthesis to maintain the structural integrity of the sarcolemma (the muscle cell membrane). During intense eccentric exercise, the sarcolemma experiences micro-tears. By providing an abundant pool of HMG-CoA, HMB facilitates rapid membrane repair, which clinically manifests as reduced markers of muscle damage (such as creatine kinase) and decreased delayed onset muscle soreness (DOMS).
### Pharmacokinetics of Calcium HMB MyHMB® is the calcium salt form of HMB (HMB-Ca). The addition of calcium stabilizes the molecule, making it highly suitable for powdered supplements and capsules. When ingested, HMB-Ca dissociates in the gut. Blood plasma levels of HMB peak approximately 60 to 120 minutes after ingestion of the calcium salt. The half-life of HMB in the blood is relatively short (roughly 2.5 hours), and approximately 50% of the ingested dose is excreted unchanged in the urine because the kidneys do not efficiently reabsorb it. This pharmacokinetic profile dictates the clinical dosing strategy: dividing the daily 3-gram dose into three 1-gram servings to maintain elevated plasma levels throughout the day.
Is there a downside to taking HMB? +
What does calcium HMB do for you? +
What is myHMB used for? +
What is the best HMB supplement on the market? +
Does HMB interact with anything? +
What are the negative side effects of HMB? +
Is HMB bad for high blood pressure? +
Should you take HMB at night or in the morning? +
How much HMB should I take daily? +
Can I get enough HMB from food? +
Is HMB better than Leucine? +
What is the difference between Calcium HMB and HMB Free Acid? +
Does HMB help with weight loss? +
Can older adults benefit from HMB? +
Do I need to cycle HMB? +
How long before a workout should I take Calcium HMB? +
Can I take HMB with creatine? +
Is HMB safe for women? +
Everything About MyHMB® (Calcium HMB) Article
## What is MyHMB® (Calcium HMB)?
MyHMB® is the patented, clinically researched form of Calcium Beta-Hydroxy Beta-Methylbutyrate (Calcium HMB). HMB is a naturally occurring substance in the human body, created when we metabolize the essential branched-chain amino acid (BCAA) L-leucine. While leucine is famous for its ability to trigger muscle growth, its metabolite, HMB, is the ultimate biological shield against muscle breakdown.
Despite being found in trace amounts in foods like grapefruit, alfalfa, and catfish, it is impossible to get a clinically effective dose of HMB from diet alone. Even consuming massive amounts of leucine is inefficient, as only about 5% of dietary leucine is converted into HMB. This is why direct supplementation with MyHMB® has become a staple in clinical nutrition, sports performance, and healthy aging protocols.
## How HMB Works: The Biochemistry of Muscle Preservation
To understand why HMB is so effective, you have to look at the continuous cycle of muscle turnover. Every day, your body is simultaneously building new muscle proteins (Muscle Protein Synthesis, or MPS) and breaking down old or damaged ones (Muscle Protein Breakdown, or MPB). Whether you gain, lose, or maintain muscle depends entirely on the balance between these two processes.
### 1. Inhibiting the Ubiquitin-Proteasome System (The Anticatabolic Effect) When you subject your body to stress—be it a grueling heavy lifting session, a marathon, a severe caloric deficit, or the natural aging process—your body upregulates a pathway known as the ubiquitin-proteasome system (UPS). The UPS acts like a cellular garbage disposal, tagging muscle proteins for destruction. HMB is a potent inhibitor of the UPS. By suppressing this pathway, HMB effectively puts the brakes on muscle wasting. Gram for gram, HMB is estimated to be 20 times more potent than leucine at preventing muscle breakdown.
### 2. Stimulating mTORc1 (The Anabolic Effect) While its primary role is defensive, HMB also plays an offensive role. Like leucine, HMB stimulates the mammalian target of rapamycin complex 1 (mTORc1). This is the master signaling pathway that tells your body to build new muscle tissue. While leucine is still the undisputed king of initiating MPS, HMB provides a complementary anabolic signal that helps shift the overall net protein balance into the positive.
### 3. Repairing the Sarcolemma (Cell Membrane Integrity) During intense eccentric exercise (the lowering phase of a lift), the outer membrane of your muscle cells, called the sarcolemma, sustains micro-tears. To repair these tears, the cell needs cholesterol. HMB is a direct precursor to HMG-CoA, a vital component in the localized synthesis of cholesterol within the muscle. By supplying this precursor, HMB accelerates the repair of the cell membrane, which drastically reduces markers of muscle damage (like creatine kinase) and minimizes delayed onset muscle soreness (DOMS).
## The Science and Benefits of MyHMB®
Backed by over 30 years of research, 28+ clinical studies, and multiple meta-analyses, MyHMB® is one of the most thoroughly vetted ingredients in sports nutrition.
### Mitigating Muscle Damage and Accelerating Recovery Examine.com gives HMB a 'Grade A' rating for reducing muscle damage. Studies, such as those by Nissen et al. (1996) and Knitter et al. (2000), demonstrate that athletes supplementing with HMB experience significantly less muscle damage and recover faster from both resistance and endurance training. This allows athletes to train harder, more frequently, without overtraining.
### Preserving Muscle During Caloric Restriction For bodybuilders cutting for a show or everyday individuals trying to lose weight, muscle loss is a constant threat. A caloric deficit is inherently catabolic. Park et al. (2013) demonstrated that HMB supplementation effectively attenuates muscle loss during sustained energy deficits, ensuring that the weight you lose is fat, not hard-earned muscle.
### Healthy Aging and Sarcopenia As we age, we naturally lose muscle mass and strength—a condition known as sarcopenia. This leads to frailty, loss of independence, and increased risk of falls. HMB has shown remarkable efficacy in older populations. Examine.com notes a 'Grade B' rating for improving walking ability in the elderly. By blunting the age-related increase in muscle protein breakdown, MyHMB® helps older adults maintain their strength and vitality.
## Dosing and Timing: How to Take MyHMB®
The clinical standard dose for MyHMB® is **3 grams per day** (or roughly 38mg per kg of body weight). Because HMB has a relatively short half-life in the blood (about 2.5 hours) and is excreted by the kidneys, taking the entire 3 grams at once is inefficient.
**The Optimal Protocol:** * Divide the 3g dose into three 1g servings taken throughout the day (e.g., morning, afternoon, evening). * **Pre-Workout Timing:** Because MyHMB® is a calcium salt, it takes longer to peak in the bloodstream compared to the free acid form. You should take your pre-workout dose of Calcium HMB **60 to 120 minutes before exercise** to ensure peak plasma levels during your training session. * **Loading Phase:** If you are preparing for a competition, a severe cutting phase, or a high-intensity training block, begin taking HMB 3 times daily at least 2 weeks prior to the event to allow the protective effects to build.
## Calcium HMB vs. HMB Free Acid
You may see two forms of HMB on the market: Calcium HMB (MyHMB®) and HMB Free Acid (MyHMB® Clear). * **Calcium HMB** is a powder where HMB is bound to calcium. It is highly stable, cost-effective, and has decades of safety data. Its absorption is slower, making it ideal for daily maintenance and sustained muscle protection. * **HMB Free Acid** is a liquid form that absorbs much faster, peaking in the blood in 30-60 minutes. It is more expensive but is excellent for acute, immediate pre-workout protection.
## Who Should Take MyHMB®?
1. **Athletes in Intense Training Blocks:** To reduce DOMS and recover faster. 2. **Individuals on a Diet:** To preserve lean muscle mass while in a caloric deficit. 3. **Older Adults:** To combat sarcopenia, maintain mobility, and preserve independence. 4. **Those Recovering from Injury/Surgery:** To prevent muscle atrophy during periods of bed rest or inactivity.