Histidine is an essential amino acid. Your body cannot make it, so you must get it from food or supplements. It contributes to protein structure and serves as a direct precursor to histamine, a compound tied to immune function, digestion, and circadian rhythm.
Some people supplement with histidine to maintain their general amino acid levels. Manufacturers and users occasionally raise questions about skin barrier support or joint comfort, but clear proof for these outcomes is slim. Standard advice points to taking it on an empty stomach for better absorption, a common practice with isolated amino acids.
Long-term high-dose safety data are missing. Anyone with a known histidine metabolism disorder should steer clear. If you are pregnant or nursing, stick with food sources unless a healthcare provider directs otherwise.