does hmb break a fast

Does HMB Break A Fast? When & How To Take HMB During A Fast?

Fasting and intermittent fasting have gained significant popularity in the wellness community. One common question is whether HMB, or β-Hydroxy β-methylbutyrate, breaks a fast. HMB is a supplement frequently used by athletes and individuals who fast to preserve muscle mass and enhance performance. This article will explore the answer to "Does HMB break a fast?", its impact on the fasting process, and provide best practices for incorporating HMB while fasting.


What Is Fasting And Intermittent Fasting?

Fasting is a dietary practice that involves refraining from or reducing food intake for a specific period.

Intermittent fasting, a widely practiced method of fasting, entails alternating between designated periods of eating and fasting on a regular schedule. Several forms of intermittent fasting include daily, whole-day, and time-restricted feeding.

These methods improve body composition and overall health by allowing the body to use its stored energy during fasting.

Does HMB Break A Fast?

Externships yet to be has not investigated whether HMB interrupts the fasting process.

However, it's known that HMB doesn't significantly influence insulin levels, a critical consideration when determining if a substance breaks a fast. If a sense triggers a significant insulin response, it could break a fast.

Given that HMB doesn't appear to affect insulin levels, it's generally considered safe to consume during a fast, especially for those fasting for weight loss or blood sugar management.

HMB doesn't break a fast

Does Taking HMB During A Fast Make You Lose Muscle?

Contrary to causing muscle loss, HMB is known for its potential role in preserving muscle mass.

This compound helps slow down protein breakdown, a process directly linked to muscle atrophy. It achieves this by regulating the ubiquitin-proteasome and caspase protease systems. These systems are associated with muscle wasting and bone loss [3].

Hence, incorporating HMB supplementation during a fast can potentially prevent muscle loss caused by the limited energy intake associated with the fasting regimen.

How Does HMB Help With Fasting And Intermittent Fasting?

Maintains Muscle Mass

Fasting or intermittent fasting can sometimes result in muscle loss due to an insufficient supply of energy to the body.

Nevertheless, HMB can aid in mitigating this process by enhancing muscle protein synthesis and diminishing protein breakdown, thereby effectively safeguarding muscle mass. The mTOR signaling pathway, which HMB stimulates, plays a vital role in this preservation.

Even when calorie intake is restricted, the protein synthesis process crucial for maintaining muscle mass continues, thanks to the influence of HMB.

Therefore, supplementing with HMB during fasting can be a beneficial strategy for those aiming to preserve and potentially enhance their muscle mass while still enjoying the benefits of their fasting regimen [2].

hmb supplement mantains muscle mass

Improves Exercise Performance

While the influence of HMB on exercise performance during a fasting state hasn't been directly researched, multiple studies have identified its role in improving exercise adaptation.

HMB aids in reducing exercise-induced muscle damage, promoting faster recovery, and enhancing the body's capability to endure strenuous workouts.

When fasting or in an intermittent fasting phase, these benefits help maintain or improve exercise performance despite the body's calorie-restricted state.

However, it is advised for individuals to monitor their body's response to HMB intake during fasting or intermittent fasting, as reactions can vary across individuals.

Supports Weight Loss

hmb supports weight loss

HMB is thought to support weight loss efforts, particularly during fasting periods. Fasting aims to shift the body's energy source to stored reserves, often resulting in fat loss.

However, the body may also break down muscle proteins for energy, leading to potential muscle loss. HMB, known for its muscle-preserving characteristics, can help prevent this muscle loss.

By preserving lean muscle mass during fasting, HMB indirectly supports sustainable weight loss. Maintaining muscle mass during fasting can help prevent overeating or binge eating once the fasting period ends, thus preventing potential fat reaccumulation [3].

Therefore, HMB supplementation during fasting not only aids in maintaining muscle mass but also supports a more sustainable and healthier weight loss journey.

When And How Should You Take HMB During A Fast?

In a trial involving participants aged 18-50 who were in overall good health, followed a non-meat diet, and practiced intermittent fasting, the participants were supplemented with 1g of HMB per meal, reporting no side effects [3].

However, taking a supplement of 3g of HMB at least 60 minutes before your workout is highly recommended to maximize your results.

This allows ample time for your body to absorb and utilize the HMB, promoting muscle preservation and enhancing performance. You can consume HMB in capsule form or as a powder, allowing you to choose your preferred method.

However, it's noticeable that some users have reported potential discomfort in the digestive system when using HMB during a fast. Therefore, monitoring your body's response and adjusting your HMB usage is crucial.

If you are building your muscles using HMB, this video will provide comprehensive instructions on how to take HMB for muscle growth:


Does HMB break a fast? The answer is appropriately no. HMB does not break a fast and can be a beneficial supplement during fasting or intermittent fasting. It helps preserve muscle mass, improve exercise performance and support sustainable weight loss. However, individual responses to HMB can vary, and it's always best to monitor your body's reaction when incorporating it into your fasting regimen.


[1] Arazi, H., Taati, B., & Suzuki, K. (2018). A Review of the Effects of Leucine Metabolite (β-Hydroxy-β-methylbutyrate) Supplementation and Resistance Training on Inflammatory Markers: A New Approach to Oxidative Stress and Cardiovascular Risk Factors. Antioxidants, 7(10), 148.
[2] Park, B.-S., Henning, P. C., Grant, S. C., Lee, W. J., Lee, S.-R., Arjmandi, B. H., & Kim, J.-S. (2013). HMB attenuates muscle loss during sustained energy deficit induced by calorie restriction and endurance exercise. Metabolism, 62(12), 1718–1729.
[3] Tinsley, G. M., Givan, A. H., Graybeal, A. J., Villarreal, M. I., & Cross, A. G. (2018). β-Hydroxyβ-methylbutyrate free acid alters cortisol responses, but not myofibrillar proteolysis, during a 24-h fast. British Journal of Nutrition, 119(5), 517–526.
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Ralph S. Albert, with over 10 years of expertise in nutrition and research, now heads the Research division at Vinatura Supplements. His dedication and extensive knowledge ensure top-quality articles on nutrition and health, collaborating with a skilled team. He has successfully completed The VINATURA Expertise Research Training Program, underscoring his commitment to Vinatura's mission. Ralph has also published numerous articles and conducted valuable research in the field, making him a trusted resource for individuals on their wellness journey.

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