Amino Acids & Peptides
REACH
L-leucine
CAS Number
61-90-5
EC Number
200-522-0
FEMA Number
FEMA 3297
What is L-leucine?
L-Leucine (CAS 61-90-5), also identified as E641 in food additive contexts, is an essential branched-chain amino acid.
Where is L-leucine used?
- Sports nutrition and dietary supplements: core component of BCAA blends
- Pharmaceuticals: dry powder inhaler excipient
- Food: flavor enhancer in savory applications and broths
- Cosmetics and personal care: amino acid-based moisturizing systems
- It supports muscle protein synthesis signaling and drives product label claims in protein powders.
Commercial specifications
- Food-grade, USP, Ph. Eur. and FCC grades
- Bulk bags and smaller packaged quantities
Other Names (Synonyms)
Leucine|L-α-aminoisocaproic acid|L-Leu|L-alpha-Aminoisocaproic acid|4-methyl-L-norvaline|2-amino-4-methylvaleric acid|(S)-leucine|(S)-2-amino-4-methylvaleric acid|E641
What are the physical properties of L-leucine?
Melting Point 293 °C
Boiling Point 295 °C (approx)
Density 1.32 g/cm³
Flash Point 145-148°C
Appearance White crystalline powder
Color White to Off-white
Odor Odorless
Form powder
Water Solubility 22.4 g/L (20 C)
Vapor Pressure <1 hPa (20 °C)
Refractive Index 1.4630 (estimate)
pH 5.5-6.5 (20g/l, H2O, 20℃)
Log P 0.80
Which trade and regulatory codes apply to L-leucine?
HS Code 29224995
Storage Class 11 - Combustible Solids
WGK (Germany) 3