About Histidine
Essential amino acid and precursor to histamine and carnosine; a component of dietary protein so most people are replete. It has the strongest standalone signal in this cluster: small placebo-controlled pilot RCTs of ~4 g/day reported improved insulin resistance and lower inflammatory markers in obese women with metabolic syndrome, and reduced eczema severity in atopic dermatitis (SCORAD/EASI improvements). These are single, small, pilot-scale trials, so the finding is promising but not yet confirmed. Graded low (not moderate) pending replication; note the pilot RCTs honestly.
What Histidine supports
- Small pilot trials suggest reduced eczema severity at ~4 g/day
- Pilot data hint at improved insulin resistance in metabolic syndrome
How much Histidine to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
500–4000
mg
No established general therapeutic dose; nominal range for a blend component. Pilot RCTs used ~4 g/day (adults, metabolic syndrome and atopic dermatitis) and ~0.8 g/day (young children, eczema).
Clinical evidence
Limited clinical evidence. Essential amino acid; small pilot RCTs (metabolic syndrome, eczema) at ~4 g/day, unreplicated.
NIH Fact Sheet