Does L-tyrosine interact with NDRIs?

There is a low potential for adverse interactions, and no research has been published documenting adverse interactions. However, it’s important to check with your physician or a pharmacist before using L-tyrosine supplements while taking NDRIs.

Norepinephrine and dopamine reuptake inhibitors (NDRIs) are a class of pharmaceuticals used to treat depression, which work by suppressing the absorption of the catecholamines dopamine and norepinephrine within neurons. Their mechanism of action involves blocking a negative feedback mechanism by suppressing a specialized group of receptors responsible for the reuptake of catecholamines within the synapses of neurons. By suppressing norepinephrine/dopamine reuptake, NDRIs prolong the ability of these neurotransmitters to propagate signals in the CNS. L-tyrosine can be converted to catecholamines such as dopamine and norepinephrine by the enzyme tyrosine hydroxylase, but this enzyme is feedback inhibited when catecholamine levels are elevated.^[1] In other words, increased catecholamine levels from concurrent NDRI use would likely suppress the enzyme tyrosine hydroxylase, reducing the potential of adverse interactions while taking L-tyrosine supplements.

Although this feedback-inhibition loop limits the potential of adverse reactions on paper, it is unclear whether there are any variations within individuals that increase the risk of adverse reactions. It’s also important to keep in mind that if you’re taking NDRIs, L-tyrosine supplements may have little effect on dopamine or norepinephrine levels — the primary reason for taking tyrosine supplements in the first place.