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Limited evidencePhysical performance

HICA (Alpha-Hydroxyisocaproic Acid)

A minor leucine metabolite sold for lean mass and reduced soreness. One small positive trial in soccer players was not confirmed by later, better-controlled resistance-training studies.

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What the science says

  • Lean mass in trained athletes Limited evidence

    A single 4-week randomized trial in 15 soccer players reported about 0.4 kg more lean mass with 1.5 g/day of HICA than placebo. The sample was very small and the finding has not been replicated.

  • No effect with resistance training Limited evidence

    A 10-week randomized trial in resistance-trained men found no effect of HICA (or HMB) on body composition, and a companion report found no effect on strength or muscle thickness. These are the largest and best-controlled data available, and they are negative.

  • Muscle soreness Limited evidence

    Reduced delayed-onset muscle soreness was a secondary outcome in the same small soccer trial, with no independent confirmation. Treat it as a hypothesis rather than a result.

Dosage & safety

Studied doseTrials used 1.5 g/day, split into three 500 mg doses with meals, for 4–10 weeks.
SafetyWell tolerated in trials lasting up to 10 weeks, with no notable adverse effects reported. There are no long-term safety data, and no data in adolescents, pregnancy or breastfeeding.

How to take it

TimingSplit it into three 500 mg doses across the day, as the trials did.
With food?Take each dose with a meal.
Worth knowingThe whole case for HICA rests on one small trial in soccer players, so treat any product's claims as far ahead of the evidence.

Frequently asked questions

Does HICA build muscle?

HICA has limited evidence for muscle: one 4-week trial in 15 soccer players reported about 0.4 kg more lean mass, but a larger 10-week trial in resistance-trained men found no effect of HICA on body composition, strength or muscle thickness. The best-controlled HICA data are negative.

Does HICA reduce muscle soreness?

Reduced muscle soreness with HICA was only a secondary outcome in one small soccer trial, with no independent confirmation. Treat the HICA soreness claim as a hypothesis, not a result.

How much HICA should I take?

HICA trials used 1.5 g/day, split into three 500 mg doses with meals, for 4–10 weeks. HICA was well tolerated for up to 10 weeks, but there are no long-term safety data.

Scientific references

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