Leucic acid

Amino-acidLeucine metabolite

What is it

Leucic acid is another name for alpha-hydroxyisocaproic acid (HICA), the end metabolite of leucine catabolism, marketed as a sport supplement for muscle recovery and lean mass.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Muscle recovery/lean mass

Limited Evidence

One small RCT in athletes; not robustly replicated.

How it works

Leucic acid is formed from leucine via transamination to alpha-ketoisocaproate and reduction. It may provide substrate for muscle protein synthesis and modestly inhibit muscle protein breakdown. A small Finnish trial in soccer players (Mero 2010) reported reductions in soreness and small lean-mass increases at 1.5 g/day; replication is sparse and overall evidence is limited compared with leucine, HMB, or whole-protein supplementation.

Dosage

No RDA. Studied at 1.5 g/day split into three 500 mg doses.

When and how to take it

Studied in divided doses around training; specific timing relative to exercise not well established.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Calcium HICA salt

Powder or capsule.

Most studied form.

Safety

Generally well tolerated at studied doses. Long-term safety data are limited.

Who should be cautious

No specific cautions. People with severe kidney or liver disease should consult a clinician before any amino acid metabolite supplement.

Interactions

No significant clinical interactions reported.

Frequently asked questions

Is leucic acid the same as HICA?⌄

Yes, both names refer to alpha-hydroxyisocaproic acid.

Is it better than leucine?⌄

Evidence is weaker. Leucine and whole-protein supplementation have stronger and more consistent data.

References

Leucic acid on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Leucic acid (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.