Last update: Oct. 20, 2016


Very Low Risk for breastfeeding

Not risky for breastfeeding or infant.

Lysine is an essential amino acid that is not produced by the body and must be taken from the diet.
It is found in large amount in legumes, cereals, red meat, sea fish, cheese and eggs. It is crucial for the synthesis of proteins in the body and multiple metabolic functions.
Often used as a dietary supplement without scientific evidence that would support any benefit of it.

Breastmilk contains it naturally with a highest concentration in the colostrum followed by a decrease within the first month after birth (Harper 1984, 1986 Janas, Spevacek 2015).
The concentration of lysine together with other amino acids and proteins is higher in the milk of mothers of preterm infants than in mothers of term infants (Atkinson 1980).
Pasteurization slightly decreases the concentration of lysine and other amino acids (Silvestre 2006, Valentine 2010) but increases the amount of bioavailable lysine (Baro 2011).

It is excreted into breast milk in clinically non-significant amount (0.5% of the administered dose) and as a part of proteins (Irving 1988, Thomas 1991).
When used as a supplementation is considered to be safe during breastfeeding (Amir 2011, The Royal Women's Hospital Fact Sheet 2013)


We do not have alternatives for Lysine since it is relatively safe.

Suggestions made at e-lactancia are done by APILAM´s pediatricians and pharmacists, and are based on updated scientific publications.
It is not intended to replace the relationship you have with your doctor but to compound it.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Lysine is also known as

Lysine in other languages or writings:


Main tradenames from several countries containing Lysine in its composition:


Variable Value Unit
Bioavailability 83 %
Molecular weight 146 daltons
T1/2 3,7 hours
M/P ratio 1,4 -


  1. Spevacek AR, Smilowitz JT, Chin EL, Underwood MA, German JB, Slupsky CM. Infant Maturity at Birth Reveals Minor Differences in the Maternal Milk Metabolome in the First Month of Lactation. J Nutr. 2015 Abstract
  2. The Royal Women’s Hospital Victoria Australia. Herbal and Traditional Medicines in Breasfeeding. Fact Sheet. 2013 Full text (link to original source) Full text (in our servers)
  3. Baro C, Giribaldi M, Arslanoglu S, Giuffrida MG, Dellavalle G, Conti A, Tonetto P, Biasini A, Coscia A, Fabris C, Moro GE, Cavallarin L, Bertino E. Effect of two pasteurization methods on the protein content of human milk. Front Biosci (Elite Ed). 2011 Abstract
  4. Amir LH, Pirotta MV, Raval M. Breastfeeding--evidence based guidelines for the use of medicines. Aust Fam Physician. 2011 Abstract Full text (link to original source) Full text (in our servers)
  5. Valentine CJ, Morrow G, Fernandez S, Gulati P, Bartholomew D, Long D, Welty SE, Morrow AL, Rogers LK. Docosahexaenoic Acid and Amino Acid Contents in Pasteurized Donor Milk are Low for Preterm Infants. J Pediatr. 2010 Abstract
  6. Silvestre D, Ferrer E, Gayá J, Jareño E, Miranda M, Muriach M, Romero FJ. Available lysine content in human milk: stability during manipulation prior to ingestion. Biofactors. 2006 Abstract
  7. Thomas MR, Irving CS, Reeds PJ, Malphus EW, Wong WW, Boutton TW, Klein PD. Lysine and protein metabolism in the young lactating woman. Eur J Clin Nutr. 1991 Abstract
  8. Irving CS, Malphus EW, Thomas MR, Marks L, Klein PD. Infused and ingested labeled lysines: appearance in human-milk proteins. Am J Clin Nutr. 1988 Abstract
  9. Janas LM, Picciano MF. Quantities of amino acids ingested by human milk-fed infants. J Pediatr. 1986 Abstract
  10. Harzer G, Franzke V, Bindels JG. Human milk nonprotein nitrogen components: changing patterns of free amino acids and urea in the course of early lactation. Am J Clin Nutr. 1984 Abstract
  11. Atkinson SA, Anderson GH, Bryan MH. Human milk: comparison of the nitrogen composition in milk from mothers of premature and full-term infants. Am J Clin Nutr. 1980 Abstract

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e-lactancia is a resource recommended by Academy of Breastfeeding Medicine from United States of America

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