Lysine & Breastfeeding

Lysine, an essential amino acid, is found in protein-rich foods and dietary supplements. Although your body needs lysine, it is unable to produce it and must obtain the amino acid through dietary sources. While eating food sources that contain lysine is considered safe, research is lacking on the safety of taking lysine supplements while breastfeeding. Consult your physician before using lysine or other dietary supplements while breastfeeding.


Lysine plays a role in your body's development, calcium absorption and production of collagen, flexible tissue responsible for healthy cartilage and skin. The amino acid is found naturally in protein-rich foods such as red meat, soy protein, dairy products and legumes. Most people get enough lysine through a balanced diet; however, a lysine deficiency may require dietary supplements.

Proposed Benefits

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Lysine plays an important role in the body's production of carnitine, an essential amino acid responsible for converting fat into energy and lowering lipoprotein cholesterol levels. The University of Maryland Medical Center reports that lysine supplements may prevent or minimize an outbreak of genital or oral herpes. Lysine does not provide any benefits directly related to breastfeeding. Talk to your health care provider before using lysine supplements as oral or genital herpes treatment while breastfeeding.

Side Effects

Side effects may occur as a result of using lysine supplements while breastfeeding. High amounts of lysine may cause abdominal pain, gallstones or gastrointestinal issues in nursing mothers. A severe allergic reaction, though rare, may occur while using lysine supplements. If you or your infant experience symptoms such as facial swelling, hives or breathing problems, stop taking lysine immediately and seek medical attention. As of 2011, no scientific research exists on the safety of lysine and breastfed infants.


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Mothers who are breastfeeding should avoid using lysine supplements due to a lack of scientific evidence on the safety of the supplement. Do not use lysine supplements if you suffer from kidney or liver disease, high cholesterol or gallstones. Again, always consult your health care provider before taking lysine or any other supplement while nursing.