Humans need tryptophan amino acid for healthy development. Tryptophan is necessary for the production of hormones such as serotonin and melatonin, vitamins such as niacin. It is an essential amino acid, the body can not make it itself. Therefore, it must be obtained from dietary sources.

The US Food and Nutrition Board makes recommendations for the Dietary Reference Intakes (DRI) such as the Estimated Average Requirement (EAR) and Recommended Daily Allowances (RDA) of nutrients for healthy individuals, for North Americans.

Here are the EAR and RDA for tryptophan. The requirements are in mg per kg of body per day.

Tryptophan Daily Requirements (DRI)

The daily requirement for tryptophan per kg of body varies depending on age (infants vs kids vs adults), life stage (e.g., pregnancy, lactation) and gender.

Age, gender, life stage group Tryptophan EAR (mg/kg/day)  Tryptophan RDA (mg/kg/day)
0–6 month   28
7–12 month 9 13
1–3 years 6 8
4–8 years 5 6
9–13 years 5 6
14–18 years 4 5
9–13 years 5 6
14–18 years 5 6
Adult Men and Women
19 and older 4 5
Pregnant Women
All ages 5 7
Lactating Women
All ages 7 9

Note: The EAR is the daily average amount estimated to be sufficient for the average (median) healthy person. The RDA is the daily average estimate most healhty individuals need.


Tryptophan related content:
High tryptophan food sources: vegetarian, meat and milk products



Friedman M. (2018). Analysis, Nutrition, and Health Benefits of Tryptophan. Int J Tryptophan Res. 2018;11:1178646918802282. Published 2018 Sep 26. doi:10.1177/1178646918802282

Institute of Medicine (2006). Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press.