| Analysis | Description | Test Method |
| Assay (dry basis) | 99.0～101.0% | HPLC |
| Loss on drying | Not More Than 0.20% | Dryer |
| Residue on ignition | Not More Than 0.10% | Ph. Eur. |
| Related substances | Not More Than 0.5% | Ph. Eur. |
| Endotoxin* | Less Than 6.0 EU/g | Ph. Eur. |
| State of solution(Transmittance) | Not Less Than 98.0% | Ph. Eur. |
| PH | 5.5～6.5 | Ph. Eur. |
| Specific rotation[α]20D | +14.9～+16.0° | Ph. Eur. |
| Specific rotation[α]25D | +14.9～+17.3° | Ph. Eur. |
| Ammonium (NH4) | Not More Than 0.020% | Ph. Eur. |
| Chloride (Cl) | Not More Than 0.020% | Ph. Eur. |
| Sulfate (SO4) | Not More Than 0.020% | Ph. Eur. |
| Iron (Fe) | Not More Than 10 ppm | ICP-MS/AOAC 993.14 |
| Arsenic (As) | < 1 ppm | ICP-MS/AOAC 993.14 |
| Cadmium (Cd) | < 2 ppm | ICP-MS/AOAC 993.14 |
| Heavy metals (Pb) | Not More Than 10 ppm | ICP-MS/AOAC 993.14 |
| Mercury (Hg) | < 0.5 ppm | ICP-MS/AOAC 993.14 |
| Total Plate Count | < 3,000 cfu/g | AOAC 990.12 |
| Total Yeast & Mold | < 300 cfu/g | AOAC 997.02 |
| E. Coli | < 10 cfu/g | AOAC 991.14 |
| Coliforms | < 10 cfu/g | AOAC 991.14 |
| Salmonella | Negative | ELFA-AOAC |
| Staphylococcus | < 10 cfu/g | AOAC 2003.07 |
Leucine is an essential amino acid for protein synthesis. Additionally, similarly to other amino acids, the carbon skeleton of leucine can be used to generate ATP. However, leucine can also regulate several cellular processes such as protein synthesis, tissue regeneration, and metabolism.