4-Hydroxybenzoic acid

4-Hydroxybenzoic acid is a phenolic compound that serves as a substrate for the enzyme monoamine oxidase B (MAOB). Despite good absorption and blood-brain barrier permeability, no clinical health benefits have been documented in human studies.

Origin & History

4-Hydroxybenzoic acid (PHBA) is a monohydroxybenzoic acid and phenolic derivative of benzoic acid that occurs naturally in all living species including bacteria, plants, and foods. It appears as a white crystalline solid with a nutty and phenolic taste, and is typically produced synthetically or extracted from natural plant sources, though specific extraction methods are not detailed in available data.

Historical & Cultural Context

No historical context, traditional medicine systems, or documented durations of use are available in the research sources. The compound's traditional applications remain undocumented.

Health Benefits

• No clinical health benefits documented - available research only describes enzyme interactions (PMID:11049757)
• Substrate for amine oxidase enzyme MAOB - biochemical role only, no therapeutic evidence
• High intestinal absorption (0.9872) and blood-brain barrier permeability (0.532) - pharmacokinetic properties only
• Component of ubiquitous natural occurrence in foods - nutritional exposure, not therapeutic benefit
• No human clinical trials, RCTs, or meta-analyses available for health claims

How It Works

4-Hydroxybenzoic acid functions as a substrate for monoamine oxidase B (MAOB), an enzyme involved in neurotransmitter metabolism. The compound demonstrates high intestinal absorption (0.9872) and moderate blood-brain barrier permeability (0.532). However, these biochemical interactions have not translated into documented therapeutic effects in clinical research.

Scientific Research

No human clinical trials, RCTs, or meta-analyses have been identified for 4-hydroxybenzoic acid as a therapeutic agent. The PMIDs mentioned (11049757, 11134050, 20493079, 8316221, 8665924) relate only to enzyme interaction studies, not clinical outcomes.

Clinical Summary

Current research on 4-hydroxybenzoic acid is limited to enzyme interaction studies, with PMID:11049757 describing its role as an MAOB substrate. No randomized controlled trials have evaluated health benefits in human subjects. The available evidence consists only of pharmacokinetic and biochemical studies examining enzyme interactions. Clinical efficacy remains unestablished despite favorable absorption properties.

Nutritional Profile

4-Hydroxybenzoic acid (4-HBA) is a phenolic acid compound (molecular formula C7H6O4, MW 138.12 g/mol), not a macronutrient or conventional micronutrient. It is a naturally occurring hydroxylated benzoic acid derivative found ubiquitously in plant-based foods. Macronutrient content: negligible (consumed in trace/microgram quantities, not as a caloric source). Protein, fat, fiber content: not applicable as an isolated compound. Bioactive compound classification: simple phenolic acid / benzoic acid derivative with a para-hydroxyl group. Naturally occurring concentrations in foods: approximately 0.1–5 mg/kg in olives, olive oil, red wine, berries (blueberries, raspberries), black radish, and some fermented foods; detected at lower levels in green tea and some spices. Also produced endogenously as a microbial metabolite from polyphenol fermentation in the gut (e.g., from hydrolysis of esters like p-hydroxybenzoate esters). Pharmacokinetic profile: high intestinal absorption (predicted absorption coefficient 0.9872), blood-brain barrier permeability coefficient 0.532 (moderately permeable), suggesting near-complete gastrointestinal uptake when ingested. Acts as a biochemical substrate for monoamine oxidase B (MAOB) enzyme. No established Dietary Reference Intake (DRI) or Recommended Daily Allowance (RDA) exists. Typical estimated dietary intake from food sources is in the range of low micrograms to low milligrams per day depending on diet composition.

Preparation & Dosage

No clinically studied dosage ranges, forms, or standardization details are available as no human trials have been documented. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

No synergistic compounds identified in available research

Safety & Interactions

Safety data for 4-hydroxybenzoic acid supplementation is limited due to lack of human clinical trials. Its interaction with monoamine oxidase B suggests potential effects on neurotransmitter metabolism, which could theoretically interact with MAO inhibitor medications. Pregnant and breastfeeding women should avoid supplementation due to insufficient safety data. Individuals taking antidepressants or other neuropsychiatric medications should consult healthcare providers before use.