Amino acids are the “building blocks” the body uses to build protein. The most noteworthy among these amino acids is leucine.
Leucine (aka the “king” of amino acids) serves as the “anabolic trigger” of muscle protein synthesis (MPS) since it activates the mechanistic target of rapamycin (mTOR), the pathway that fuels muscle growth (anabolism).
But, that’s not all.
Not only does leucine ignite muscle growth and repair, it also helps limit protein breakdown (catabolism)
Given the prominence of leucine regarding both its anabolic and anti-catabolic properties, it’s no wonder that protein researchers and sports scientists have investigated the amino acids’ two primary metabolites (breakdown products) -- β-hydroxy-β-methylbutyrate (HMB) and α-hydroxyisocaproic acid (α-HICA).
Today, we discuss what HMB and HICA is as well as what benefits are to be had from supplementing with these two compounds.
Let’s get started.
HICA
HICA stands for Alpha-Hydroxy-Isocaproic Acid and, as we just mentioned above, it is a metabolite of the branched-chain amino acid (BCAA), leucine -- the “anabolic trigger” of protein synthesis in the body.
You may also see HICA referred to at times as leucic acid.
As a metabolite of leucine, HICA helps protect against muscle breakdown due to its anti-catabolic properties (meaning it inhibits protein breakdown).[1]
The reason this is important is that prolonged bouts of exercise and/or periods of dieting on low calories places muscles at risk for increased breakdown.[2]
Supplementing with HICA may help protect against excessive muscle damage and protein breakdown, thereby reducing the duration and severity of muscle soreness. This ultimately allows you to train more frequently and with greater intensity, which is vital to seeing results in the gym.
Our New women's pre workout formula includes 500mg dose of HICA per serving
Women's Pre-Workout also includes performance boosting ingredients Citruline and Beta-Alaine (Carnosyn) and a synergistic combination of fast and slow-acting energy and full Stress Suppressing Matrix to sustain performance no matter how long or intense you train.
HMB
HMB stands for β-hydroxy-β-methylbutyrate. Similar to HICA, HMB is another derivative of leucine metabolism in the body.
As a metabolite of leucine, HMB is capable of activating mTOR and stimulating protein synthesis in the body.[3]
However, these mTOR-activating properties aren’t quite as powerful as leucine[4], which is why much of the focus on HMB centers around its anti-catabolic properties, which help reduce the rate of muscle breakdown.
In this sense, you can think of HMB as an indirect muscle building ingredient.
If you remember, building muscle ultimately boils down to muscle protein synthesis being greater than muscle protein breakdown over the long haul.
Therefore, anything that:
- Increases protein synthesis (i.e. leucine, BCAAs, EAAs, whey protein, etc.), or
- Reduces protein breakdown (HMB, HICA, BCAAs, leucine)
Tilts the muscle building balance in favor.
Beyond its ability to support muscle growth, supplementing with HMB may also be beneficial for those dieting.
Anytime the body is in a negative energy balance (hypocaloric diet), there is an increased risk of protein breakdown. To prevent muscle loss, it is recommended to consume a high-protein diet while cutting.
Supplementing with anti-catabolic agents like HMB or HICA may further help reduce the potential for muscle breakdown during prolonged periods of dieting.
1UP Pre Women Includes 1,000mg HMB along with an additional 500mg HICA to resist protein breakdown and support training performance.
References
- Mero, A., Ojala, T., Hulmi, J., Puurtinen, R., Karila, T., & Seppälä, T. (2010). Effects of alfa-hydroxy-isocaproic acid on body composition, DOMS and performance in athletes. Journal of the International Society of Sports Nutrition, 7, 1.
- Willoughby D, Hewlings S, Kalman D. Body Composition Changes in Weight Loss: Strategies and Supplementation for Maintaining Lean Body Mass, a Brief Review. Nutrients. 2018;10(12):1876. Published 2018 Dec 3. doi:10.3390/nu10121876
- Duan, Y., Li, F., Li, Y., Tang, Y., Kong, X., Feng, Z., Yin, Y. (2015). The role of leucine and its metabolites in protein and energy metabolism. Amino Acids, 48(1), 41-51. doi:10.1007/s00726-015-2067-1
- Wilkinson DJ, et al. Effects of Leucine and its metabolite, β-hydroxy-β-methylbutyrate (HMB) on human skeletal muscle protein metabolism. J Physiol. (2013)
