What it does in the body
- Collagen synthesis and crosslinking
- Carnitine biosynthesis for fatty acid oxidation
- Calcium absorption enhancement
- Antiviral defense (HSV competition with arginine)
- Growth hormone secretion support
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 30mg/kg/day (~2.1g for 70kg) | WHO/FAO/UNU |
| Adult female | 30mg/kg/day (~1.8g for 60kg) | WHO/FAO/UNU |
| Pregnancy | 38mg/kg/day | WHO |
| Children | 35-58mg/kg/day depending on age | WHO |
| Older adults | 30mg/kg/day | WHO |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Beef (lean, cooked) | 2.5g per 100g | global |
| Chicken breast (cooked) | 2.3g per 100g | global |
| Cod (cooked) | 2.2g per 100g | global |
| Tofu (firm) | 1.0g per 100g | east-asia |
| Lentils (cooked) | 0.6g per 100g | south-asia |
| Parmesan cheese | 3.3g per 100g | europe |
| Sardines (canned) | 1.9g per 100g | mediterranean |
| Black-eyed peas (cooked) | 0.5g per 100g | west-africa |
If you don't get enough
Mild: Fatigue, poor concentration, reduced appetite, slow wound healing
Moderate: Impaired growth in children, reproductive disorders, anemia, immunodeficiency
Severe: Severe growth retardation, fatty acid oxidation defects (carnitine deficiency), connective tissue disorders
Time to onset: Growth effects in children within weeks; adults may tolerate suboptimal intake longer (4-8 weeks before clinical signs)
Too much
Upper limit: No established UL; doses up to 6g/day used therapeutically without major adverse effects
High doses may cause GI distress, diarrhea, abdominal cramps. Theoretical risk of increased calcium absorption causing hypercalcemia in susceptible individuals
How well you absorb it
90-95% from animal proteins; 70-85% from plant sources
Helped by: Vitamin C (required for lysine hydroxylation in collagen synthesis), Iron and vitamin B6, Adequate caloric intake
Hindered by: Maillard reaction products (lysine reacts with reducing sugars during browning), High arginine intake (competitive), Phytates
Cooking & storage
Lysine is the amino acid most susceptible to Maillard reaction damage. Toasting bread, baking, and browning reactions can reduce available lysine by 10-40%. Gentle cooking methods preserve it best.
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