Mechanism of Action
Lysine is incorporated into polypeptide chains during protein translation. Once integrated into collagen, it undergoes hydroxylation (addition of a hydroxyl group) catalysed by vitamin C. The resulting hydroxylysine residues enable glycosylation and cross-linking of fibres, two processes that give collagen its mechanical strength.
In a parallel pathway, lysine is converted to trimethyllysine and then to carnitine through a series of reactions involving iron, vitamin C and vitamin B6. Carnitine shuttles long-chain fatty acids into the mitochondrial matrix, where they are oxidised to produce ATP (the cell's energy currency).
At the intestinal level, lysine promotes active calcium transport across the mucosa. It also reduces renal calcium excretion. These two mechanisms converge to maintain a positive calcium balance, supporting bone tissue integrity.
Key Benefits
- Moderate
Indispensable amino acid for muscle protein synthesis. As a non-synthesisable essential component, its intake directly determines protein anabolism, particularly in the context of ageing where protein synthesis slows down.
- Moderate
Obligatory metabolic precursor of carnitine, a molecule that transports fatty acids to mitochondria for energy production. Insufficient lysine intake can limit endogenous carnitine synthesis.
- Moderate
Provides a key residue for collagen cross-linking. Hydroxylysine, formed after post-translational modification of lysine, stabilises the collagen triple helix and gives connective tissues their mechanical strength.
- Moderate
A controlled trial in 108 adults shows that co-supplementation of L-lysine and L-arginine (2.64 g/day each for one week) significantly reduces salivary cortisol levels and self-reported anxiety.
- Moderate
A randomised trial in adult women demonstrates that L-lysine supplementation increases intestinal calcium absorption and reduces urinary calcium excretion, contributing to a positive calcium balance.
- Moderate
An interventional study in Ghana shows that dietary lysine fortification reduces morbidity and improves several nutritional status markers in poor peri-urban households in Accra.
Dosage & Forms
Several oral forms exist: free-base L-lysine, L-lysine hydrochloride (HCl) and, less commonly, acetyl-L-lysine. The HCl form contains approximately 80% active lysine and offers markedly higher solubility than the free base, promoting rapid dissolution in the digestive tract.
Dosages studied in clinical trials range from 500 mg to 3,000 mg per day depending on the objective. Stress-related studies use doses of 2,640 mg/day in co-supplementation with L-arginine. Research on calcium metabolism uses 400 to 800 mg/day. No upper safety limit (UL) has been defined by European authorities for dietary lysine, but doses up to 3 g/day are well tolerated in the literature.
Singular selects the HCl form for its oral bioavailability and compatibility with the powder matrix. The dosage is individually calibrated according to the user's nutritional profile.
In the Singular Formula
Inclusion rationale
Essential amino acid that the body cannot synthesize. L-lysine is a structural constituent of collagen, where it participates in the cross-links that stabilize the triple helix, the molecular architecture responsible for collagen's mechanical strength. In the formula, it forms part of a coherent collagen support network alongside type I collagen peptides, glycine and vitamin C (an indispensable cofactor for the hydroxylation of lysine and proline in the collagen matrix). Beyond its structural role, lysine is a precursor of carnitine, a molecule involved in the transport of fatty acids to mitochondria for energy production from fats. It also facilitates intestinal calcium absorption and reduces urinary calcium excretion, indirectly contributing to the maintenance of bone mineral density. Vegetarian and vegan diets may present a risk of insufficient lysine intake, as cereals are relatively low in this amino acid.
Selected form
Vegan-grade L-Lysine HCl, obtained through microbial fermentation from corn. Lysine is an essential amino acid: the body cannot synthesise it, so it must be obtained from the diet. The hydrochloride (HCl) form ensures superior stability and solubility compared to free-base L-lysine. The plant-based fermentation process avoids any animal source and guarantees high purity. Quality: vegan, non-GMO.
Formula dosage
0 to 500 mg.
Synergies in the formula
Linked Biomarkers
Safety & Precautions
L-Lysine benefits from several decades of dietary use. Doses up to 3 g per day are well tolerated in healthy adults. Mild digestive discomfort (nausea, abdominal cramps, diarrhoea) may occur at high doses, generally above 10 g/day.
Lysine promotes calcium absorption. Individuals with a history of calcium-based kidney stones should consult a healthcare professional before supplementing. No significant interactions with common nutrients have been reported.
Supplementation is not recommended during pregnancy and breastfeeding due to insufficient data. Children under 18 should be supervised by a healthcare professional.
Scientific Studies
| Authors | Year | Type | Journal | |
|---|---|---|---|---|
| Smriga M et al. | 2007 | Randomised Controlled Trial | Biomedical Research | View on PubMed |
Oral treatment with L-lysine and L-arginine reduces anxiety and basal cortisol levels in healthy humans Controlled trial in 108 healthy Japanese adults. Lysine-arginine co-supplementation (2.64 g/day each for 7 days) reduces salivary cortisol and anxiety scores compared to placebo. | ||||
| Smriga M et al. | 2004 | Randomised Controlled Trial | Proceedings of the National Academy of Sciences | View on PubMed |
Lysine fortification reduces anxiety and lessens stress in family members in economically weak communities in Northwest Syria Randomised interventional trial in 93 Syrian families. Lysine fortification of cereals reduces chronic anxiety and cortisol levels in a population with insufficient lysine intake. | ||||
| Civitelli R et al. | 1992 | Randomised Controlled Trial | Nutrition | View on PubMed |
Dietary L-lysine and calcium metabolism in humans Controlled trial evaluating the effect of L-lysine (400 mg/day) on calcium absorption and excretion in adult women. Supplementation increases intestinal absorption and reduces renal calcium excretion. | ||||
| Ghosh S et al. | 2010 | Cohort Study | American Journal of Clinical Nutrition | View on PubMed |
Effect of lysine supplementation on health and morbidity in subjects belonging to poor peri-urban households in Accra, Ghana Interventional study in Ghana showing that lysine fortification (2 g/day for 12 weeks) reduces the frequency of infectious episodes and improves immune status in populations with low protein intake. | ||||
| Flodin NW | 1997 | Systematic Review | Journal of the American College of Nutrition | View on PubMed |
The metabolic roles, pharmacology, and toxicology of lysine Comprehensive review of lysine metabolic roles: collagen synthesis, carnitine biosynthesis, calcium absorption and safety profile. Foundational reference on the nutritional pharmacology of this amino acid. | ||||
| Hussain T et al. | 2004 | Randomised Controlled Trial | Food and Nutrition Bulletin | View on PubMed |
Lysine fortification of wheat flour improves selected indices of the nutritional status of predominantly cereal-eating families in Pakistan Lysine fortification trial of wheat flour in Pakistani families. Supplementation improves weight, height and protein status markers in children and adults. | ||||