From the article, they mentioned that taking tryptophan or eating foods with tryptophan in them, reduces the uptake of tryptophan due to amino acid competition:

From the article, they mentioned that taking tryptophan or eating foods with tryptophan in them, reduces the uptake of tryptophan due to amino acid competition: > There is competition between the various amino acids for the transport system, so after the ingestion of a meal containing protein, the rise in the plasma level of the other large neutral amino acids will prevent the rise in plasma tryptophan from increasing brain tryptophan So possible OP took it on an empty stomach which spiked the levels in the body?