What is L-Lysine (L-Lysine)?
L-lysine is an essential amino acid that cannot be synthesized in the body and must be obtained through diet. It is the first limiting amino acid in cereal-based diets. It plays a role in protein synthesis, collagen cross-linking, carnitine biosynthesis, and calcium metabolism.
- CAS number: 56-87-1
- Molecular formula: C₆H₁₄N₂O₂
What is L-Lysine Used For? Why is it Used?
L-lysine is an essential amino acid and the weakest link in cereal-based proteins; it plays a key role in food fortification and protein complementation. Its physiological roles in collagen cross-linking and carnitine synthesis are clear; however, there is no EFSA approval for specific health claims such as herpes, bone, and calcium, and clinical evidence is inconsistent.
Usage as Sports Nutrition
The following information is based on sports nutrition research (ISSN position stands, randomized controlled trials, and meta-analyses); the level of evidence is clearly stated for each item.
- Protein synthesis and collagen: As an essential amino acid, it is a building block of muscle protein synthesis and contributes to the cross-linking of collagen fibers (connective tissue durability). It completes the amino acid profile in sports protein blends.
- Progenitor of carnitine: Lysine is a precursor in the biosynthesis of carnitine, which plays a role in fatty acid metabolism; this pathway is associated with energy production (physiological role; ergogenic benefit is not proven).
- Stress/anxiety (limited evidence): It was reported that lysine fortification reduces anxiety in populations with cereal-based diets in a PNAS study (Smriga 2004). This is in the context of dietary deficiency; it cannot be generalized to athletes (honest).
Forms and Differences
L-Lysine is offered in different forms; form selection is made based on bioavailability, stability, and purpose of use:
- L-Lysine hydrochloride (L-Lysine HCl, food grade): The most common form in food and supplements is L-lysine monohydrochloride; it is produced by fermentation (Corynebacterium glutamicum) and is more stable and convenient than the hygroscopic free base. It is the standard for food fortification.
- L-Lysine sulfate / liquid lysine (feed grade): Lysine sulfate and concentrated liquid lysine HCl forms are used as animal feed additives (evaluated by EFSA FEEDAP).
Usage in Dietary Supplements
- Protein complementation: Cereal proteins are poor in lysine; lysine supplementation corrects the amino acid score, thereby increasing protein bioavailability. It is important in vegan/cereal-heavy diets.
- Herpes simplex (mixed evidence): There is one randomized crossover study reporting that 1,248 mg/day of L-lysine HCl reduces recurrent herpes attacks; however, other studies failed. The evidence is inconsistent — it is likely ineffective at doses below 1 g/day (honest).
Usage in the Food Industry
- Food fortification: Adding food-grade L-lysine to improve protein quality in cereal products and plant-based milk alternatives (oat/almond milk) is a common industrial practice.
- Animal feed additive: Lysine is the first limiting amino acid in pigs and the second in poultry; it is one of the most produced amino acids worldwide as a feed additive (fermentation).
Effects on Health
- Collagen cross-linking: Lysine and hydroxylysine residues are involved in the cross-linking of collagen and elastin fibers; this gives connective tissue tensile strength (established physiology).
- Calcium metabolism: Some data suggest that lysine increases intestinal calcium absorption and reduces renal excretion; however, EFSA has not authorized this calcium/bone claim.
- Protein and carnitine synthesis: It is required for general protein synthesis and carnitine production; deficiency negatively affects growth and tissue repair.
Status of Health Claims (EFSA) — Transparent Information
EFSA has NOT AUTHORIZED/REJECTED claims regarding L-lysine's immune defense against herpes virus, normal LDL cholesterol, increased appetite/energy intake, contribution to normal protein synthesis, normal bone maintenance, and increased calcium absorption (EFSA Journal 2011;9(4):2063) due to lack of cause-and-effect relationship. The expressions here are not claims but are based on established physiology and RCTs.
Usage Limits and Safety
- Typical usage dose: Typical 1-3 g/day in supplements; ~1.2-3 g/day in herpes studies
- Upper intake level (UL): No established UL; gastrointestinal discomfort may occur at high doses (honest: no definitive UL).
- Turkish legislation (Sports Foods / TETGK): Used as an essential amino acid in the Turkish Food Codex Dietary Supplements legislation; an official numerical upper limit for L-lysine could not be verified by me — the number is NOT FABRICATED; the manufacturer's Communiqué should be followed.
Individuals with kidney failure and those carrying lysinuric protein intolerance should consult a physician.
Technical Specifications
| Parameter | Value |
|---|---|
| Moisture | ≤5.0 % |
| Total Heavy Metals | ≤10 ppm |
| E. Coli | Negative in 10 g |
| Salmonella | Negative in 25 g |
| Solubility | Soluble in Water |
Scientific Studies
The following independent studies relate to this component's effect on sports performance, bioavailability, and efficacy (study types are specified):
- PubMed 6435961 — Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride
- PubMed 15159538 — Lysine enrichment reduces anxiety and relieves stress in economically disadvantaged communities in Northwest Syria
Technical Documents and Supply — Asuka Kimya
You can contact Asuka Kimya for SDS, TDS, CoA and supply conditions for L-Lysine.
References
The usage, sports nutrition, and health information on this page have been compiled from official legislation/institution sources (EFSA, NIH ODS, ISSN, Turkish Food Codex Sports Foods / Dietary Supplements Communiqué) and independent scientific publications (PubMed). The product is a food supplement/sports nutrition raw material; it does not aim to diagnose or treat disease.