Is HICA Effective for Athletes? Examining the Scientific Evidence

January 8, 2026 •

4 min read

According to a 2010 study published in the Journal of the International Society of Sports Nutrition, soccer players supplementing with HICA experienced less muscle soreness and slightly greater lean body mass gains over a four-week period. These preliminary findings have fueled a growing interest among athletes, prompting the critical question: is HICA effective for athletes, and what does the wider body of evidence truly indicate?

Quick Summary

HICA is a leucine metabolite with purported anti-catabolic effects that may help reduce muscle soreness and preserve lean mass during periods of intense training, but the scientific evidence is limited and mixed.

Key Points

Limited Evidence: The scientific research on HICA's effectiveness for athletes is currently limited to a few small, short-term human studies.
Anti-Catabolic Function: HICA's primary proposed benefit is its anti-catabolic effect, meaning it may help reduce muscle protein breakdown, particularly during periods of intense training or dieting.
Reduces Muscle Soreness: Some studies suggest HICA supplementation can lead to reduced delayed onset muscle soreness (DOMS) in athletes.
Modest Muscle Gain: While some research indicates small increases in lean body mass, these effects appear modest and may only occur under specific, high-intensity training conditions.
Contextual Use: HICA may be most beneficial for athletes undergoing rigorous training phases or cutting cycles where muscle preservation is a key concern, rather than for general muscle growth.
Not for Strength Gains: Studies have not shown a significant improvement in strength or athletic performance with HICA supplementation.

What is HICA?

HICA, or alpha-hydroxyisocaproic acid (also known as leucic acid), is a natural metabolite of the branched-chain amino acid (BCAA) leucine. It is produced in small amounts within the body's muscle and connective tissues as part of the leucine degradation pathway. While leucine is renowned for its direct role in triggering muscle protein synthesis, HICA is thought to exert its benefits differently, primarily through its anti-catabolic properties. Traces of HICA can be found in fermented foods like wine, sake, and cheese, but not in sufficient quantities to elicit the effects seen in supplement studies.

The Proposed Mechanism of Action

Unlike its parent amino acid leucine, HICA's potential effectiveness for athletes is not primarily linked to stimulating muscle protein synthesis via the mTOR pathway. Instead, research points to a different function—one of protecting muscle tissue from breaking down, a process known as catabolism. Intensive exercise and periods of caloric restriction can increase catabolic activity, leading to muscle damage and soreness. The proposed mechanism for HICA involves:

Inhibiting Muscle Protein Breakdown: HICA is thought to interfere with proteolytic (protein-degrading) pathways, which can reduce the rate at which muscle tissue is broken down. By minimizing this breakdown, HICA could help maintain muscle mass, especially during demanding training blocks.
Reducing Muscle Soreness: Through its anti-catabolic action and potentially via anti-inflammatory effects, HICA has been linked to a reduction in delayed onset muscle soreness (DOMS). This could lead to faster recovery times and the ability to train more frequently and intensely.

Reviewing the Scientific Evidence: The Good and the Mixed

The body of scientific evidence on HICA is limited and not as robust as for other supplements like creatine or protein. What exists is largely based on a few small, short-term human studies and some animal research.

Supporting Research

The 2010 Soccer Player Study: The most frequently cited study involved male soccer players taking HICA daily for four weeks during an intensive training period. The HICA group saw a small but statistically significant increase in lean body mass, particularly in the legs, and reported less overall muscle soreness compared to the placebo group.
Animal Studies on Recovery: Some animal research has indicated that HICA may speed up muscle recovery after a period of atrophy (muscle wasting). This suggests its anti-catabolic effect might be most pronounced in states of physiological stress or disuse.

Contradictory Evidence

The 2025 Resistance Training Study: An 8-week randomized controlled trial, available on ResearchGate, found no significant difference in fat-free mass, muscle thickness, or performance between trained men supplementing with HICA or a placebo. This suggests HICA's effectiveness may be dependent on the training context and intensity.
In-Vitro Studies: Some cellular-level research has paradoxically shown that HICA might decrease basal protein synthesis under normal conditions but successfully attenuates muscle atrophy under catabolic conditions. This highlights the complexity of its mechanism and the need for more human-based research.

HICA vs. Leucine vs. HMB: A Comparison

To understand HICA's place in sports nutrition, it is useful to compare it with other well-known supplements, particularly its parent amino acid leucine and its fellow metabolite HMB (beta-hydroxy-beta-methylbutyrate).


Feature	HICA (Alpha-Hydroxyisocaproic Acid)	Leucine (L-Leucine)	HMB (Beta-Hydroxy-Beta-Methylbutyrate)
Primary Mechanism	Anti-catabolic (inhibits protein breakdown)	Anabolic (stimulates protein synthesis via mTOR)	Anti-catabolic (inhibits protein breakdown)
Primary Benefit	May preserve muscle mass and reduce DOMS during intense training	Maximizes muscle growth and recovery	May aid in muscle preservation and reduce catabolism
Evidence Strength	Weak to moderate; based on small, short-term human studies	Strong; extensive research supports its role in MPS	Stronger than HICA, especially for muscle preservation
Best For	Bodybuilders or athletes in intense, catabolic phases or cutting cycles	Most athletes aiming for muscle growth, strength, and recovery	Those looking to minimize muscle loss, especially during dieting

Practical Considerations for Athletes

Considering the mixed evidence, is HICA worth taking? Here are some points to consider:

Context is key: HICA's benefits appear most prominent during periods of high-intensity training or caloric deficits, when the body is more prone to catabolism. If you are bulking or training with moderate intensity, other supplements may be more effective.
Manage expectations: HICA is not a 'magical' muscle builder. The gains in lean mass observed in studies were modest. For significant muscle growth, focusing on overall protein intake, including adequate leucine, remains far more critical.
Consistency is important to see any potential benefits.
Safety profile: Short-term use of HICA appears safe, with no reported side effects in studies. However, long-term safety has not been thoroughly investigated, and more research is needed. Consult with a healthcare professional before starting any new supplement.

Conclusion

So, is HICA effective for athletes? The current scientific consensus is cautiously optimistic but reserved. While small studies suggest it may help reduce muscle soreness and preserve lean mass during intense, catabolic training periods, the evidence is not strong enough to recommend it as a primary muscle-building supplement. More research is needed to fully understand its mechanism and effectiveness, especially compared to its more extensively studied counterparts like leucine and HMB. For most athletes, prioritizing foundational sports nutrition, including a high-protein diet rich in leucine, will yield more reliable results. HICA may be a secondary consideration for those seeking a potential edge during specific, strenuous training cycles, with the understanding that its effects are likely modest. For deeper insights into the primary human study, refer to the research published in the Journal of the International Society of Sports Nutrition: Effects of alfa-hydroxy-isocaproic acid on body composition, DOMS and performance in athletes.

Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before starting any new supplement regimen.

Frequently Asked Questions

HICA, or alpha-hydroxyisocaproic acid, is a metabolite of the branched-chain amino acid (BCAA) leucine. It is naturally produced in the body during the breakdown of leucine and is available in supplement form.

Leucine is a primary trigger for muscle protein synthesis through the mTOR pathway. In contrast, HICA is thought to work primarily as an anti-catabolic agent, reducing muscle protein breakdown rather than directly stimulating new muscle growth.

Evidence for HICA directly building muscle is modest and mixed. While some small studies show slight increases in lean mass during intensive training, other research has found no significant benefit. Its primary function seems to be muscle preservation during stressful periods.

HMB is another leucine metabolite with a longer history of research, mainly focused on its anti-catabolic effects. HMB research is more extensive, and while both may have similar functions, more robust evidence supports HMB for muscle preservation. HICA research is still in its early stages.

Based on the most prominent human studies, HICA is often recommended to be taken with meals or around workouts. It is important to follow the product's instructions or consult a healthcare professional for guidance.

Short-term studies have not reported any significant adverse side effects associated with HICA supplementation at typical usage levels. However, long-term safety data is lacking, and more extensive research is needed. Always consult a healthcare professional about potential side effects.

HICA may be most relevant for athletes who are in a prolonged, intensive training phase or a dieting (cutting) phase where there is an increased risk of muscle protein breakdown and soreness. It is not recommended for general, less intense training where other supplements are more proven.