L-Histidine

Histidine

Snapshot

Indications	Contraindications
Atopic dermatitis¹ Insulin resistance² Body fat in metabolic syndrome² Adjunct in cholera³ Genetic hearing and vision loss⁴	Liver disease^{5, 6} Schizophrenia or bipolar depression⁷

L-Histidine is an essential amino acid that the body converts to histamine and carnosine and builds into skin barrier protein, with roles in metal chelation and antioxidant defense⁵. Supplementation is used to support the skin barrier in atopic dermatitis¹. It is also used for insulin resistance and body fat in obese women with metabolic syndrome. It is studied as an adjunct to oral rehydration in cholera and as daily therapy in a genetic hearing and vision disorder. Circulating histidine falls in chronic kidney disease and chronic obstructive pulmonary disease⁸.

In atopic dermatitis, small placebo-controlled pilot studies in adults and young children reported lower severity scores¹. Many products list histidine, mostly as powders and capsules; see Form comparison.

The reason behind the liver caution is that histidine administration raised ammonia and glutamine and lowered branched-chain amino acids^{5, 6}. Per product labeling in the United States, a practitioner's approval is asked before use⁷.

Last updated October 17, 2026. Read how we make monographs.

In the full monograph

46 sources, 35 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources