Dr. Grey AI

Histidine

Histidine is one of nine essential amino acids that humans must obtain from diet. Unique among amino acids for its imidazole side chain, which allows it to participate in acid-base buffering and metal ion coordination. Precursor to histamine (immune mediator) and carnosine (muscle buffer). Found abundantly in meat, fish, eggs, and dairy. NO GRADED OUTCOMES for supplementation - deficiency is rare in developed countries. May have roles in anemia (enhances iron absorption), zinc status, and possibly cognitive function via histamine pathways. Generally obtained adequately through protein-rich diets; supplementation typically unnecessary unless specific deficiency suspected.

Quick Answer

What it is

Histidine is one of nine essential amino acids that humans must obtain from diet. Unique among amino acids for its imidazole side chain, which allows it to participate in acid-base buffering and metal ion coordination.

Key findings

  • Grade D: Iron Status
  • Grade D: Hemoglobin Synthesis
  • Grade D: Carnosine Levels

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts: Histidine

Quick Facts: Histidine

  • Best Evidence:Grade D
  • Conditions Studied:2
  • Research Outcomes:4
  • Key Effect:Blood Health
Outcomes by grade:
A0
B0
C0
D4
2 conditions · 4 outcomes

Detailed Outcomes

|
D
Iron Status
Limited human research suggests histidine supplementation may improve iron status and enhance iron absorption in iron-deficiency anemia. Biochemically, histidine is critical for hemoglobin structure and oxygen binding, and animal studies confirm its importance in hemoglobin synthesis. Evidence remains preliminary with no large controlled trials.
2 studies
small↑Improves
D
Hemoglobin Synthesis
Animal studies demonstrate histidine is essential for hemoglobin synthesis, and histidine deficiency causes growth retardation. The imidazole side chain of histidine plays a critical structural role in hemoglobin's oxygen-binding capacity. Human supplementation data supporting improved hemoglobin levels is very limited.
2 studies
small↑Improves
D
Carnosine Levels
In vitro studies confirm histidine is a direct precursor to carnosine (synthesized with beta-alanine), which serves as an intramuscular buffer and antioxidant. While the biochemical pathway is well-established, no controlled trials have specifically examined oral histidine supplementation for increasing muscle carnosine in humans.
1 study
small↑Improves
D
Atopic Dermatitis Symptoms
Limited human studies have explored histidine supplementation in atopic dermatitis, potentially related to its role in filaggrin production (a histidine-rich protein important for skin barrier function). Evidence is preliminary and insufficient for clinical recommendations.
1 study
small↓Improves

Related Supplements

Lactosucrose

1 shared condition · 5 outcomes

Lactosucrose is a trisaccharide (three-sugar molecule) composed of galactose, glucose, and fructose linked by glycosidic bonds. It functions as a prebiotic, selectively feeding beneficial gut bacteria (particularly Bifidobacteria). NO GRADED OUTCOMES - limited research. Similar in concept to FOS (fructooligosaccharides) and GOS (galactooligosaccharides) as a prebiotic fiber. Found in small amounts in some foods; also manufactured for use in functional foods and supplements. May support gut health and mineral absorption. Generally well-tolerated; excess may cause gas and bloating as with other prebiotics.

Lactobacillus acidophilus

1 shared condition · 12 outcomes

Lactobacillus acidophilus is one of the most commonly used probiotic species, found naturally in the human GI tract and vagina, and in fermented foods like yogurt. Research supports its use as an adjuvant treatment for diarrhea, including antibiotic-associated diarrhea. Also studied for vaginal health, cholesterol, and immune function. Generally safe and well-tolerated. NO GRADED OUTCOMES but substantial overall research. Effects are strain-dependent - different L. acidophilus strains may have different properties. One of the most accessible and well-established probiotic options.

L-Cysteine

1 shared condition · 5 outcomes

L-Cysteine is a semi-essential (conditionally essential) amino acid that the body can synthesize from methionine under normal conditions. It's the rate-limiting precursor for glutathione (the body's master antioxidant), and also forms taurine, sulfate, and contributes to coenzyme A synthesis. Used for hair/nail health (keratin contains cysteine). More commonly supplemented as N-acetyl cysteine (NAC), which has better bioavailability and is better researched. Safe at normal doses but very high doses may have pro-oxidant effects. NO specific GRADED OUTCOMES for isolated L-cysteine; NAC has more research.

Japanese catnip

1 shared condition · 4 outcomes

Schizonepeta tenuifolia (Japanese Catnip or Jing Jie) is a traditional Chinese/Korean medicinal herb used for colds, headaches, and allergic skin conditions. NOT related to common catnip (Nepeta cataria). NO GRADED OUTCOMES - only animal and in vitro research exists. Shows moderate anti-inflammatory effects (compared to indomethacin in one study) and may suppress allergic responses. Known as an 'immunomodulator' but human evidence is completely lacking. Contains volatile oils (pulegone, menthone) and flavonoids. Cannot recommend use without human research.

Haninjin

1 shared condition · 7 outcomes

Artemisia iwayomogi (Haninjin) is a Korean herb in the mugwort/wormwood family with limited traditional use but emerging preclinical research. NO GRADED OUTCOMES - only animal and in vitro studies exist. May have anti-allergic, anti-obesity (PPARδ activation), and anti-cancer properties based on preliminary research. Contains sesquiterpenes, flavonoids, and coumarins. NOT to be confused with other Artemisia species (A. annua for malaria, A. absinthium for absinthe). Human evidence is completely lacking - research is too preliminary for any recommendations.

Essential fatty acid (EFA)

1 shared condition · 12 outcomes

Essential fatty acids (EFAs) are polyunsaturated fats that humans cannot synthesize and must obtain from diet. Two families exist: omega-3 (alpha-linolenic acid/ALA) and omega-6 (linoleic acid/LA). NO GRADED OUTCOMES in this database - see specific supplements (fish oil, omega-3, omega-6) for evidence. Omega-3s (EPA, DHA) have extensive cardiovascular and anti-inflammatory evidence. Most Western diets are omega-6 heavy; increasing omega-3 intake is generally recommended. The omega-6:omega-3 ratio matters for inflammation balance. Deficiency is rare but causes dermatitis, poor wound healing, and growth impairment.