Supplements do promise revolutionary results, but few have stood the test of scientific scrutiny like β-Hydroxy β-Methylbutyrate (HMB). Whether you're a competitive athlete pushing your limits, an older adult looking to maintain strength, or someone recovering from injury, HMB is uniquely positioned to help.
Today, we’ll explore what HMB is, how it works, and why it might be the missing piece in your journey to live a fit, healthy, and vibrant life.
What is HMB?
HMB is a naturally occurring metabolite of leucine, one of the branched-chain amino acids (BCAAs) required for protein synthesis. While the body can produce HMB from leucine found in protein-rich foods like fish, poultry, red meat, and whey protein, only about 5% of dietary leucine is converted into HMB. Typically, our bodies produce ~0.3 grams per day…but this is an entire order of magnitude lower than the amount shown in research to support lean muscle mass.
Further complicating the matter is that HMB is not abundant in foods. It’s only found in small amounts in certain foods like catfish, grapefruit, and alfalfa (among others).
What this means is that if you want to get the full benefits of HMB, then supplementation is necessary.
How Does HMB Work?
Leucine is renowned for its anabolic (muscle building) properties. This is due to the fact that leucine is that “trigger” that activates mTOR, which subsequently stimulates protein synthesis -- the biological process that fuels muscle recovery and growth.
As a metabolite (by-product) of leucine, you might think it has a similar effect in the body, but that’s not exactly true. You see, HMB isn’t as effective as leucine at stimulating protein synthesis.
However, it is a more effective anticatabolic agent than leucine.
You see, building lean muscle is a matter of protein synthesis (anabolism) outpacing protein breakdown (catabolism).
By limiting protein breakdown, HMB can help your muscles spend more time in an anabolic state, which supports greater lean muscle gains.
HMB also supports muscle cell proliferation and differentiation by influencing factors like MyoD and myogenin, and it may enhance cell membrane integrity through cholesterol synthesis.[1]
Basically, HMB helps limit muscle breakdown and increase protein synthesis, making it particularly useful during periods of high stress, such as intense training or calorie restriction (dieting).
Benefits for Muscle Preservation and Growth
HMB shines in scenarios where muscle loss is a risk, such as[2,3]:
- Periods of aggressive dieting
- Injury (and you can’t engage in resistance training)
- Middle-aged to older adults dealing with sarcopenia
- In-season competitive athletes
HMB helps reduce exercise-induced muscle damage, soreness, and biomarkers like creatine kinase, allowing for faster recovery and potentially better performance over time. Due to its anticatabolic properties, it can also limit the amount of muscle loss during periods when you won’t be able to train consistently, such as rehabbing an injury or battling a prolonged illness.
For individuals looking to build lean muscle (not just retain it), pairing HMB with creatine monohydrate (alongside progressive resistance training) has been shown to be beneficial.[4,5] To top things off, HMB increases mitochondrial biogenesis, which, in turn, boosts oxidative function, increasing aerobic capacity.[6]
Scientific Evidence: What Do the Studies Say?
HMB has been investigated quite thoroughly over the past few decades and continues today. This is great news as many supplements are only ever studied a handful of times. The benefit of having a larger body of scientific literature is that it allows researchers to conduct systematic reviews and meta-analyses (a study of studies).
Most recently, a meta-analysis is Nutrients (a highly respected scientific journal) concluded that “HMB supplementation combined with RT may yield modest improvements in functional performance, particularly handgrip strength and overall physical function…”[3]
Another recent scientific review stated that HMB enhances protein synthesis by up to 70% and reduces breakdown (up to 57%).[7]
What’s the Research-Backed Dosage?
The standard dosage backed by research is 3 grams per day, typically divided into two 1.5 gram doses.
A “loading” phase is not needed for HMB, unlike other supplements. Instead, we would suggest taking a dose of HMB before your workout and the second dose after your workout (or before bed).
Conclusion
HMB is a metabolite of leucine, the “king” of amino acids. Its power lies in protecting muscles from breakdown and promoting a favorable environment for lean muscle gain, especially for those dieting and/or older adults.
1UP Creatine + Tone & Define supplies a 1.5g of HMB in each serving along with a full 5g of creatine monohydrate and CaloriBurn GP. As we mentioned above, the combination of HMB + creatine has been well-studied and shown to support exercise performance and lean mass gains.
Creatine + Tone & Define can be used standalone, and it can be stacked with our other creatine products for additional benefits, depending on your goals (fat loss, muscle gain, body recomposition, etc.).
- For increased workout performance, we suggest having a serving of 1UP Pre Women or Pre-Workout Tone & Define (which contains a full gram of HMB), and having a serving of Creatine + Tone & Define post workout.
References
- Kaczka P, Michalczyk MM, Jastrząb R, Gawelczyk M, Kubicka K. Mechanism of Action and the Effect of Beta-Hydroxy-Beta-Methylbutyrate (HMB) Supplementation on Different Types of Physical Performance - A Systematic Review. J Hum Kinet. 2019 Aug 21;68:211-222. doi: 10.2478/hukin-2019-0070. PMID: 31531146; PMCID: PMC6724588.
- Bear, D. E., Langan, A., Dimidi, E., Wandrag, L., Harridge, S. D. R., Hart, N., Connolly, B., & Whelan, K. (2019). β-Hydroxy-β-methylbutyrate and its impact on skeletal muscle mass and physical function in clinical practice: a systematic review and meta-analysis. The American Journal of Clinical Nutrition, 109(4), 1119–1132. https://doi.org/10.1093/ajcn/nqy373
- García-Alonso A, Sánchez-González JL, Navarro-López V, Méndez-Sánchez R, Polo-Ferrero L. The Role of HMB Supplementation in Enhancing the Effects of Resistance Training in Older Adults: A Systematic Review and Meta-Analysis on Muscle Quality, Body Composition, and Physical Function. Nutrients. 2025 Nov 20;17(22):3624. doi: 10.3390/nu17223624. PMID: 41305674; PMCID: PMC12655442.
- Fernández-Landa J, Calleja-González J, León-Guereño P, Caballero-García A, Córdova A, Mielgo-Ayuso J. Effect of the Combination of Creatine Monohydrate Plus HMB Supplementation on Sports Performance, Body Composition, Markers of Muscle Damage and Hormone Status: A Systematic Review. Nutrients. 2019 Oct 20;11(10):2528. doi: 10.3390/nu11102528. PMID: 31635165; PMCID: PMC6835217.
- Fernández-Landa, J., Fernández-Lázaro, D., Calleja-González, J., Caballero-García, A., Córdova, A., León-Guereño, P., & Mielgo-Ayuso, J. (2020). Long-Term Effect of Combination of Creatine Monohydrate Plus β-Hydroxy β-Methylbutyrate (HMB) on Exercise-Induced Muscle Damage and Anabolic/Catabolic Hormones in Elite Male Endurance Athletes. Biomolecules, 10(1), 140. https://doi.org/10.3390/biom10010140
- Bideshki MV, Behzadi M, Jamali M, Jamilian P, Zarezadeh M, Gargari BP. Ergogenic Benefits of β-Hydroxy-β-Methyl Butyrate (HMB) Supplementation on Body Composition and Muscle Strength: An Umbrella Review of Meta-Analyses. J Cachexia Sarcopenia Muscle. 2025 Feb;16(1):e13671. doi: 10.1002/jcsm.13671. PMID: 39797501; PMCID: PMC11724150.
- Sadeghi B, Bahari H, Jozi H, Hasanzadeh MA, Hashemi D, Bideshki MV. Effects of β-hydroxy-β-methylbutyrate (HMB) supplementation on lipid profile in adults: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials. Front Nutr. 2024 Sep 25;11:1451282. doi: 10.3389/fnut.2024.1451282. PMID: 39385778; PMCID: PMC11462179.
