Leucic acid (HICA)
Summary
HICA is a breakdown product of the amino acid leucine marketed for muscle gain. One 4-week trial in 15 soccer players found slightly more lean mass and less soreness with 1.5 g a day, but a later 8-week trial in trained men found no body-composition benefit (grade D). Long-term safety has not been studied.
Key facts
- Two small trials: one positive (15 soccer players), one null (20 men in the HICA and placebo arms)[1][2]
- 1.5 g/day (500 mg three times a day) for 4 weeks[1]
- 500 mg per tablet; 3–6 tablets a day (1.5–3 g) by body weight[4]
- In mouse muscle cells, HICA lowered basal protein synthesis but limited breakdown under inflammatory stress[3]
- Authors of the positive trial held a HICA patent[1]
- 2 graded human outcomes on this page
- October 13, 2026
How it works
ProposedHICA is an end product of leucine metabolism in muscle and connective tissue and has been described as anti-catabolic. In mouse muscle cells it lowered basal protein synthesis but reduced protein breakdown and cell shrinkage under inflammatory stress, so whether it helps muscle in people is unclear.[1][3]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Fat-free mass and performance during resistance training | No effect | Grade D | RCT · n = 20 · 2019 Resistance-trained young men Form: Off-the-shelf α-HICA supplement (HMB arms also tested) · Dose: As labelled on the commercial product (amount not given in the abstract) · Duration: 8 weeks α-HICA did not improve body composition more than placebo; no between-group differences. | 30588860 (opens PubMed)Source [2] |
| Lean body mass, muscle soreness, strength and running speed | Improved | Grade D | RCT · n = 15 · 2010 Male soccer players during an intensive training period Form: Sodium salt of HICA mixed in liquid · Dose: 583 mg sodium HICA (500 mg HICA) three times a day (1.5 g/day) · Duration: 4 weeks Whole-body lean mass rose and leg lean mass rose 400 g (vs a 150 g fall with placebo); muscle soreness was lower in week 4. Strength and running speed did not differ. | 20051111 (opens PubMed)Source [1] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Sodium HICA (powder or tablets) | 86%[1] | No human absorption data.[1] | The 4-week trial abstract does not report adverse effects, and long-term data are lacking.[1] | Lean mass and muscle soreness in athletes |
Compound weight → elemental active
500 mg sodium hica (powder or tablets) ≈ 430 mg elemental active
Studied doses
Doses studied in human trials ranged from 1.5 g a day for 4 weeks in soccer players to an off-the-shelf α-HICA product for 8 weeks in trained men (amount not reported in the abstract).[1][2]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Anyone expecting long-term use
- The longest human trial lasted 8 weeks, so long-term safety is unknown.[2]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
- Per tablet vs per dayOne label lists 500 mg of HICA per tablet with 3 tablets (1.5 g) a day up to 150 lb and 6 tablets (3 g) above that; the only positive trial used 1.5 g a day.[4][1]
- Salt formThe trial dose was given as sodium HICA, where 583 mg supplies 500 mg of HICA; check whether a label states the salt or the acid.[1]
Cost per studied dose, without the sales pitch
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Cost per studied dose
Enter the price, servings and the amount per serving from your label.
Frequently asked questions
What is HICA?
Alpha-hydroxyisocaproic acid, also called leucic acid, is an end product of leucine metabolism in muscle and connective tissue.[1]
Does HICA build muscle?
One 4-week trial of 15 soccer players found a small lean-mass gain with 1.5 g a day, but an 8-week trial in trained men found no benefit over placebo.[1][2]
Does HICA reduce muscle soreness?
The 2010 soccer trial reported lower whole-body soreness in week 4; no other trial has tested this.[1]
How much HICA is in a typical product?
One label lists 500 mg per tablet and 3–6 tablets a day depending on body weight.[4]
Sources
- [1]Effects of alfa-hydroxy-isocaproic acid on body composition, DOMS and performance in athletes.. J Int Soc Sports Nutr, 2010. RCT
- [2]No effect of HMB or α-HICA supplementation on training-induced changes in body composition.. Eur J Sport Sci, 2019. RCT
- [3]α-Hydroxyisocaproic Acid Decreases Protein Synthesis but Attenuates TNFα/IFNγ Co-Exposure-Induced Protein Degradation and Myotube Atrophy via Suppression of iNOS and IL-6 in Murine C2C12 Myotube.. Nutrients, 2021. animal-study
- [4]HICA-Max Muscle Growth Support (Labrada Nutrition), DSLD label 62514: 500 mg HICA per chewable tablet; 3 tablets (1.5 g) daily up to 150 lb body weight, 6 tablets (3 g) over 150 lb. NIH Office of Dietary Supplements, Dietary Supplement Label Database, 2016. label
What changed
- Strict adversarial pass: PMIDs re-checked; randomisation, salt form and patent conflicts of the 2010 trial confirmed in the PMC full text. Grade D for both trials; DSLD label verified as 500 mg per tablet, 3–6 tablets a day.
- First draft rebuilt from scratch after the earlier draft files were lost. Every PMID checked against NCBI esummary and abstracts read for each row; randomisation, dose form and competing interests of the 2010 trial confirmed in the PMC full text. Label re-read from the DSLD API: 500 mg HICA is per tablet, with 3–6 tablets per day.