Lysine

amino acid
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Lysine is one of the nine essential amino acids necessary for human health. It serves as a fundamental building block for proteins and contributes to various physiological processes. Because the body cannot synthesize lysine, it must be acquired through dietary sources or supplements. Its functions include supporting healthy growth and development, facilitating the absorption of calcium, and aiding in the formation of collagen, a protein required for bones, skin, tendons, and cartilage. Lysine is also involved in the production of enzymes, hormones, and antibodies, which support immune function and physiological balance. Furthermore, lysine plays a role in energy production and fat metabolism and may help maintain blood vessel integrity. It is recognized for its potential to support the immune system, particularly when managing certain viral challenges, making it a useful component of a balanced nutritional approach.

Natural sources
Meat (beef, pork, chicken)Fish (cod, sardines)Dairy products (cheese, milk, yogurt)EggsLegumes (soybeans, lentils, chickpeas)QuinoaTofuNuts and seeds (pumpkin seeds, cashews)

Ingredient forms

No public comparison lists found.

Optimal Dosage
Minimum1000 mg
Maximum3000 mg
Safety & Toxicity
3 safety notes
  • Individuals with kidney or liver disease should consult a healthcare professional before taking lysine supplements.
  • Pregnant or breastfeeding women should seek medical advice prior to supplementation.
  • High doses might affect cholesterol levels in susceptible individuals.
Goals
Bone Health
Bone Health
Impact
High effect
Typical dose:500–2000 mg

Lysine supports bone health through calcium absorption and retention and through collagen cross-linking. These roles contribute to both the mineral strength and flexibility of bone.

Focuses on
Bone DensityCollagen Matrix
Most relevant for
Women looking to improve calcium utilization and maintain bone mineral density.

Potential benefits

  • Calcium Absorption Support.Clinical trials indicate that lysine can enhance how the intestines absorb calcium, especially in individuals with existing bone loss.
  • Renal Calcium Conservation.Lysine may help the kidneys retain calcium that has already been absorbed, which helps support a more positive mineral balance in the body.
  • Collagen Matrix Support.Unconfirmed. Lysine is structurally necessary for collagen cross-linking in bones, but it is unproven whether additional supplementation significantly impacts bone flexibility or strength.

Limitations

  • Indirect Markers.Current research tracks intermediate markers like calcium movement rather than definitive outcomes like long-term bone density gains or fracture prevention.
  • Dietary Confounding.Associations between lysine and bone health are often tied to total dietary protein intake, making it difficult to isolate the effect of lysine as a standalone supplement.
  • Population Specificity.Most human evidence for lysine's role in calcium metabolism and bone density is derived from studies focused specifically on women.

Study evidence

2 studies

Lysine may support calcium absorption, and higher dietary intake has been associated with greater bone density in women. The available evidence is limited and does not establish that taking Lysine supplements strengthens bones or reduces osteoporosis-related fractures.

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Hair Health
Hair Health
Impact
High effect
Typical dose:500–1500 mg

L-Lysine plays a significant role in hair health by facilitating the absorption of iron and zinc, two critical minerals for hair growth. Studies suggest that adding L-Lysine to an iron supplement can be more effective at reversing shedding in women with low ferritin than taking iron alone.

Focuses on
Hair StrengthHair Shedding
Most relevant for
Women experiencing persistent hair shedding linked to low iron levels or inadequate dietary protein.

Potential benefits

  • Support for nutritional shedding.Correcting suboptimal lysine intake may help reduce persistent hair shedding when linked to specific nutritional imbalances.
  • Iron synergy.Unconfirmed. Lysine is thought to facilitate iron absorption, which is critical for hair follicle function, though its independent effect on hair is unproven.

Limitations

  • Dependent on iron status.Research suggests lysine's role is specifically tied to correcting iron deficiency; it is not established as a standalone hair growth stimulant for healthy individuals.
  • Not for genetic hair loss.There is no evidence that lysine supplementation addresses androgenetic alopecia or other forms of non-nutritional hair loss.
  • Limited clinical evidence.Evidence is primarily from narrative reviews discussing nutritional deficiencies rather than clinical trials isolating the effects of lysine alone.
Things to consider

Improving hair health through nutrition often requires several months of consistent intake and the simultaneous correction of iron or zinc deficiencies.

Study evidence

1 study

Lysine may be relevant to hair shedding when low intake accompanies depleted iron stores. The supplied evidence discusses correcting these nutritional imbalances, but does not establish that lysine alone improves hair growth or benefits people with adequate nutrition.

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Immunity
Immunity
Impact
Situational effect
Typical dose:1000–3000 mg

Lysine competes with arginine, an amino acid that the herpes virus requires to replicate. By increasing the lysine-to-arginine ratio, supplementation can reduce the frequency, duration, and severity of cold sore outbreaks. Its use is specific to this condition, not general immunity.

Focuses on
Immune NutrientsSeasonal Defense
Most relevant for
Individuals with recurrent herpes simplex outbreaks or those with limited protein diversity from wheat-heavy diets.

Potential benefits

  • Herpes Simplex Support.Research indicates lysine may reduce the frequency, severity, and healing time of outbreaks in individuals with recurrent herpes simplex infections.
  • Support for Lysine Deficiency.In cases of dietary lysine deficiency, supplementation has been shown to improve specific immune markers such as T-cell counts and antibody levels.
  • General Immunity.Unconfirmed. There is no confirmed evidence that lysine provides immune benefits or prevents infections in individuals who already consume adequate dietary protein.

Limitations

  • Context-Specific Benefits.Improved immune markers were only documented in populations with high wheat intake and existing nutritional gaps, not in well-nourished groups.
  • Narrow Viral Scope.Clinical evidence for viral defense is limited to Herpes Simplex Virus and does not support protection against other viruses or illnesses.
  • Limited Clinical Data.Findings are based on a small number of studies with specific populations, leaving broader application to general health uncertain.
Things to consider

Lysine competes with arginine, an amino acid required by the herpes virus to replicate, which is why its use is specific to managing HSV outbreaks.

Study evidence

2 studies

Lysine has shown benefits for selected immune indicators in people eating a heavily wheat-based diet and for recurrent herpes symptoms. These narrow findings do not establish that extra lysine broadly strengthens immunity or prevents infections in people whose diets already provide enough.

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Studies

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Sources

Up to five highest-ranked published examples per goal. Study counts and charts include all published studies for the connection.

  1. Amino Acid Intakes Are Associated With Bone Mineral Density and Prevalence of Low Bone Mass in Women: Evidence From Discordant Monozygotic Twins.
    Jennings A; MacGregor A; Spector T; Cassidy A · Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 2016
    Cross-sectional study135 participantsBone Health
  2. Dietary L-lysine and calcium metabolism in humans.
    Civitelli R; Villareal DT; Agnusdei D; Nardi P; Avioli LV; Gennari C · Nutrition (Burbank, Los Angeles County, Calif.) · 1993
    Clinical trial75 participantsBone Health
  3. Causes of hair loss and the developments in hair rejuvenation.
    Rushton DH; Norris MJ; Dover R; Busuttil N · International journal of cosmetic science · 2010
    Narrative reviewHair Health
  4. Lysine-fortified wheat flour improves the nutritional and immunological status of wheat-eating families in northern China.
    Zhao W; Zhai F; Zhang D; An Y; Liu Y; He Y; Ge K; Scrimshaw NS · Food and nutrition bulletin · 2004
    Clinical trial264 participantsImmunity
  5. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis
    R S Griffith, D E Walsh, K H Myrmel, R W Thompson, A Behforooz · Dermatologica · 1987
    Non-randomized trial52 participantsImmunity