Last update July 6, 2022


Low Risk

Possibly safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.

Essential amino acid that is not produced by the body and must be taken from the diet. It is naturally found in many proteins of animal and plant origin (eggs, milk, cheese, soy, marine fish, nuts). It is a precursor of serotonin (George 1989, Yurcheshen 2015) through its metabolite 5-HTP or Oxitriptan and is credited with antioxidant properties (Tsopmo 2009). There is no conclusive scientific evidence that tryptophan supplements are effective on depression, insomnia, attention deficit, other diseases or improvement of physical performance (Yurcheshen 2015). Oral administration. It is also a component of total parenteral nutrition intravenous solutions.

Tryptophan is a natural component of breast milk, with higher concentration in colostrum than in mature milk (Zarando 1989, Kamimura 1991); it has a circadian rhythm that regulates the sleep pattern and behavior of the infant. (Italianer 2020, Heine 1995, Cubero 2005)

By taking tryptophan or alpha-lactalbumin (a high tryptophan-containing protein) tryptophan levels in breast milk is not increased (Dowlati 2015), but plasma prolactin concentration doest it. (Chaney 1982, Cowen 1985)

It has been associated to a serious outbreak of Eosinophilia-Myalgia Syndrome with more than 1,500 cases and 37 deaths occurring in the 1990s, possibly caused by contaminated or poorly prepared batches of tryptophan (Falk 2011, Allen 2011, Sachs 2013, Yurcheshen 2015, Mediine Plus 2015). The FDA has launched a precautionary measure by withdrawing it from the market for years.

At high doses it may cause side effects that are harmful to health. (Fernstrom 2012)

With a comprehensive diet, tryptophan supplements are not needed at all, as their effectiveness has not been proven yet in any disease or disorder. Whenever used, a moderate consumption is recommended, making sure a reliable source since poisoning has been reported in the past. (Falk 2011, Allen 2011,Fernstrom 2012, Mediine Plus 2015)

See below the information of these related products:

  • Maternal Depression (Possibly safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.)
  • Oxytriptan (Possibly safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.)


Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

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

Tryptophan is also known as

Tryptophan in other languages or writings:


Main tradenames from several countries containing Tryptophan in its composition:


Variable Value Unit
Oral Bioavail. 69 (47 - 84) %
Molecular weight 204 daltons
VD 0.4 l/Kg
Tmax 1 - 2 hours
1.8 - 6 hours


  1. Italianer MF, Naninck EFG, Roelants JA, van der Horst GTJ, Reiss IKM, Goudoever JBV, Joosten KFM, Chaves I, Vermeulen MJ. Circadian Variation in Human Milk Composition, a Systematic Review. Nutrients. 2020 Aug 4;12(8). pii: E2328. Abstract
  2. MedlinePlus. L-tryptophan. MedlinePlus Supplements 2015 Full text (link to original source) Full text (in our servers)
  3. Mediine Plus. L-triptofano. MedlinePlus suplementos. 2015 Full text (link to original source) Full text (in our servers)
  4. Dowlati Y, Ravindran AV, Maheux M, Steiner M, Stewart DE, Meyer JH. No effect of oral L-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk. Eur Neuropsychopharmacol. 2015 Abstract
  5. FEN - Fundación Española de la Nutrición. Libro Blanco de la Nutrición en España. - 2013 Full text (link to original source)
  6. Sachs HC; Committee On Drugs. The transfer of drugs and therapeutics into human breast milk: an update on selected topics. Pediatrics. 2013 Sep;132(3):e796-809. Abstract Full text (link to original source) Full text (in our servers)
  7. Fernstrom JD. Effects and side effects associated with the non-nutritional use of tryptophan by humans. J Nutr. 2012 Abstract
  8. Allen JA, Peterson A, Sufit R, Hinchcliff ME, Mahoney JM, Wood TA, Miller FW, Whitfield ML, Varga J. Post-epidemic eosinophilia-myalgia syndrome associated with L-tryptophan. Arthritis Rheum. 2011 Abstract
  9. Falk H, Briss P. Environmental- and injury-related epidemic-assistance investigations, 1946-2005. Am J Epidemiol. 2011 Abstract
  10. Tsopmo A, Diehl-Jones BW, Aluko RE, Kitts DD, Elisia I, Friel JK. Tryptophan released from mother's milk has antioxidant properties. Pediatr Res. 2009 Abstract
  11. Cubero J, Valero V, Sánchez J, Rivero M, Parvez H, Rodríguez AB, Barriga C. The circadian rhythm of tryptophan in breast milk affects the rhythms of 6-sulfatoxymelatonin and sleep in newborn. Neuro Endocrinol Lett. 2005 Abstract
  12. Carretti N, Bertazzo A, Comai S, Costa CV, Allegri G, Petraglia F. Serum tryptophan and 5-hydroxytryptophan at birth and during post-partum days. Adv Exp Med Biol. 2003 Abstract
  13. AAP - American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89. Abstract Full text (link to original source) Full text (in our servers)
  14. Heine WE. The significance of tryptophan in infant nutrition. Adv Exp Med Biol. 1999 Abstract
  15. Villalpando S, Butte NF, Flores-Huerta S, Thotathuchery M. Qualitative analysis of human milk produced by women consuming a maize-predominant diet typical of rural Mexico. Ann Nutr Metab. 1998 Abstract
  16. Heine W, Radke M, Wutzke KD. The significance of tryptophan in human nutrition. Amino Acids. 1995 Abstract
  17. Kamimura S, Eguchi K, Sekiba K. Tryptophan and its metabolite concentrations in human plasma and breast milk during the perinatal period. Acta Med Okayama. 1991 Abstract
  18. George CF, Millar TW, Hanly PJ, Kryger MH. The effect of L-tryptophan on daytime sleep latency in normals: correlation with blood levels. Sleep. 1989 Abstract
  19. Zanardo V, Bacolla G, Biasiolo M, Allegri G. Free and bound tryptophan in human milk during early lactation. Biol Neonate. 1989 Abstract
  20. Messinis IE, Souvatzoglou A, Fais N, Lolis D. Histamine H1 receptor participation in the control of prolactin secretion in postpartum. J Endocrinol Invest. 1985 Apr;8(2):143-6. Abstract
  21. Green AR, Aronson JK, Cowen PJ. The pharmacokinetics of L-tryptophan following its intravenous and oral administration. Br J Clin Pharmacol. 1985 Abstract
  22. Cowen PJ, Gadhvi H, Gosden B, Kolakowska T. Responses of prolactin and growth hormone to L-tryptophan infusion: effects in normal subjects and schizophrenic patients receiving neuroleptics. Psychopharmacology (Berl). 1985 Abstract
  23. Charney DS, Heninger GR, Reinhard JF Jr, Sternberg DE, Hafstead KM. The effect of IV L-tryptophan on prolactin, growth hormone, and mood in healthy subjects. Psychopharmacology (Berl). 1982 Abstract
  24. Møller SE. Pharmacokinetics of tryptophan, renal handling of kynurenine and the effect of nicotinamide on its appearance in plasma and urine following L-tryptophan loading of healthy subjects. Eur J Clin Pharmacol. 1981 Abstract
  25. Magnussen I, Nielsen-Kudsk F. Bioavailability and related pharmacokinetics in man of orally administered L-5-hydroxytryptophan in steady state. Acta Pharmacol Toxicol (Copenh). 1980 Abstract
  26. Magnussen I, Nielsen-Kudsk F. Pharmacokinetics of intravenously administered L-5-hydroxytryptophan in man. Acta Pharmacol Toxicol (Copenh). 1979 Abstract

Total visits


Help us improve this entry

How to cite this entry

Do you need more information or did not found what you were looking for?

   Write us at

e-lactancia is a resource recommended by El Parto Es Nuestro of Spain

Would you like to recommend the use of e-lactancia? Write to us at corporate mail of APILAM