Essential amino acid • Collagen & bone health • Immune support. Educational profile — independent, evidence-informed overview. This content is not medical advice. Please consult your healthcare provider for personalised guidance.
🔑 Core Function
- Collagen synthesis: Vital for bone, skin, and connective tissue integrity.
- Carnitine production: Needed to make carnitine, which transports fatty acids into mitochondria for energy.
- ️ Immune support: Contributes to antibody and enzyme production.
- ⚖️ Calcium balance: Helps improve calcium absorption and may reduce urinary calcium loss.
🧬 Family & Essentiality
ClassEssential amino acid
EssentialityMust be obtained from diet
Special noteLimiting amino acid in cereal-based diets (important in vegetarian/vegan nutrition)
🌿 Plain-Language Summary
Lysine is one of the body’s core building blocks for proteins. Think of it as a structural specialist: it’s essential for collagen (skin, joints, bones) and for making carnitine, which moves fats into mitochondria for energy. It also supports immunity and calcium balance.
⚗️ Molecular & Chemical IDs
- Abbreviation: Lys / K
- Chemical formula: C₆H₁₄N₂O₂
- Structure: Basic amino acid with positively charged side chain
⚡ Functions
- ️ Structural: Collagen and elastin formation for skin, cartilage, and bone.
- Energy metabolism: Via carnitine synthesis → fatty acid transport into mitochondria.
- ️ Immune health: Supports antibody, enzyme, and hormone synthesis.
- ⚖️ Calcium handling: Enhances calcium absorption and retention.
🍽️ Absorption & Bioavailability
AbsorptionHighly bioavailable from animal proteins
NotePlant-based diets may need planning — lysine is lower in grains but rich in legumes/soy
🇦🇺 Australian NRVs (NHMRC)
- Adults (≥19 yrs) EAR: ~30 mg/kg/day
- RDI: ~38 mg/kg/day
Values based on NHMRC/FAO/WHO amino-acid requirement data, expressed per kilogram body weight.
🥗 Food Sources
- Meat, poultry, fish
- Dairy (milk, cheese, yoghurt)
- Eggs
- Legumes (beans, lentils, soy), quinoa, amaranth
Tip: Combining grains + legumes improves lysine adequacy in vegetarian diets.
🧪 Testing & Monitoring
- Plasma amino acid profiling (specialist labs).
- ❌ Not part of routine GP pathology testing.
🔄 Interactions
- ➕ Works with vitamin C for collagen formation.
- ➕ Requires adequate iron, zinc, and vitamin B6 for protein metabolism.
- ⚠️ Deficiency risk in cereal-based diets → may contribute to growth delays, fatigue, anaemia.
🚨 Deficiency & Evidence
Deficiency
Possible in poorly diversified cereal-based diets; may affect growth, immune resilience, and protein quality.
Evidence Snapshot
- ✅ Established: Essential for protein synthesis, collagen, and carnitine production.
- ⚖️ Mixed/conditional: Supplemental lysine studied for reducing herpes simplex outbreaks; evidence inconsistent.
