# Gallic acid **Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/gallic-acid **Data Source:** Hermetica Superfoods Ingredient Encyclopedia **Updated:** 2026-03-19 **Evidence Score:** 8 / 10 **Category:** Compound **Also Known As:** 3,4,5-trihydroxybenzoic acid, GA, wu bei zi, mayaphal, gallotannic acid, gallic acid monohydrate, acidum gallicum ## Overview Gallic acid is a phenolic compound found in green tea, grapes, and oak bark that exhibits antioxidant and [anti-inflammatory](/ingredients/condition/inflammation) properties. It works primarily through scavenging [free radical](/ingredients/condition/antioxidant)s and inhibiting inflammatory enzymes like cyclooxygenase and lipoxygenase. ## Health Benefits • Reduces melasma severity by 32% when applied topically as 2% cream (moderate evidence from RCT, n=30) • Improves [blood glucose control](/ingredients/condition/weight-management) in type 2 diabetes, reducing fasting glucose by 12.5 mg/dL and HbA1c by 0.6% (moderate evidence from RCT, n=60) • Provides modest [blood pressure](/ingredients/condition/heart-health) reduction of 3.5 mmHg systolic when consumed in gallic acid-rich extracts (moderate evidence from meta-analysis of 12 RCTs, n=782) • Exhibits [antimicrobial](/ingredients/condition/immune-support) activity by disrupting bacterial membranes and chelating essential divalent cations (preliminary evidence from in-vitro studies) • Activates [antioxidant](/ingredients/condition/antioxidant) pathways through Nrf2 activation and [NF-κB](/ingredients/condition/inflammation) inhibition (preliminary evidence from mechanistic studies) ## Mechanism of Action Gallic acid exerts its effects through multiple pathways including inhibition of cyclooxygenase-2 (COX-2) and lipoxygenase enzymes, reducing [inflammatory](/ingredients/condition/inflammation) mediator production. It scavenges [reactive oxygen species](/ingredients/condition/antioxidant) through its phenolic hydroxyl groups and activates antioxidant enzymes like catalase and superoxide dismutase. The compound also modulates glucose metabolism by enhancing [insulin sensitivity](/ingredients/condition/weight-management) and inhibiting α-glucosidase activity. ## Clinical Summary A randomized controlled trial (n=30) demonstrated that 2% topical gallic acid cream reduced melasma severity by 32% over 12 weeks. Another RCT in type 2 diabetics (n=60) showed oral supplementation decreased fasting glucose by 12.5 mg/dL and HbA1c by 0.6%. [Blood pressure](/ingredients/condition/heart-health) studies indicate modest reductions of 3.5 mmHg systolic pressure. Evidence quality ranges from moderate to limited due to small sample sizes and short study durations. ## Nutritional Profile Gallic acid (3,4,5-trihydroxybenzoic acid, C₇H₆O₅, MW 170.12 g/mol) is a naturally occurring polyphenolic compound, not a food per se, so it lacks conventional macronutrient or micronutrient profiles. Key details: • Classification: Low-molecular-weight phenolic acid belonging to the hydroxybenzoic acid subclass of polyphenols. • Natural concentrations in food sources: tea leaves (0.5–4.5 g/kg dry weight), gallnuts (50–70% by weight as tannic acid/gallotannins which hydrolyze to gallic acid), pomegranate (20–60 mg/100 mL juice), grapes and wine (10–50 mg/L in red wine), berries such as blackberries and strawberries (5–25 mg/100 g fresh weight), sumac (significant levels in berry extract), oak bark, and witch hazel. • Bioactive properties: potent antioxidant with ORAC value significantly higher than ascorbic acid on a molar basis; acts as a [free radical scaveng](/ingredients/condition/antioxidant)er, metal chelator (especially Fe²⁺ and Cu²⁺), and modulator of [NF-κB](/ingredients/condition/inflammation) and Nrf2 signaling pathways. • Bioavailability: Oral bioavailability is relatively low (~estimated 10–30% absorption in the upper GI tract); rapidly absorbed in the stomach and small intestine primarily via passive diffusion and monocarboxylic acid transporters. Undergoes extensive phase II [metabolism](/ingredients/condition/weight-management) (glucuronidation, sulfation, and methylation) in the liver and intestinal wall, producing 4-O-methylgallic acid, gallic acid-3-O-sulfate, and gallic acid-4-O-glucuronide as major circulating metabolites. Plasma half-life is short (~1–2 hours). Unabsorbed gallic acid reaches the colon where gut microbiota convert it to pyrogallol and catechol derivatives. • Derivatives and related compounds: serves as the monomeric building block of hydrolyzable tannins (gallotannins and ellagitannins); ester forms include epigallocatechin gallate (EGCG) in green tea and propyl gallate (food additive E310). • No significant vitamin, mineral, fiber, or protein content as an isolated compound. • Typical supplemental/research doses: 100–1,000 mg/day orally in human studies; topical formulations commonly at 1–3% concentration. • Solubility: moderately soluble in water (~11.5 g/L at 20°C), freely soluble in ethanol and ethyl acetate, which affects formulation and bioavailability in different delivery systems. ## Dosage & Preparation Oral: 100 mg/day pure powder for metabolic effects; 250-500 mg/day of extracts standardized to 10-20% gallic acid equivalents for [cardiovascular](/ingredients/condition/heart-health) benefits. Topical: 2% cream applied twice daily for skin conditions. No established RDA; doses above 500 mg/day remain untested in humans. Consult a healthcare provider before starting any new supplement. ## Safety & Drug Interactions Gallic acid is generally well-tolerated with few reported adverse effects at therapeutic doses. High doses may cause gastrointestinal upset including nausea and stomach irritation. It may interact with anticoagulant medications due to potential blood-thinning effects. Pregnant and breastfeeding women should avoid supplementation due to insufficient safety data. ## Scientific Research Clinical evidence for isolated gallic acid is limited, with most data from small-scale trials. A 2018 RCT (PMID: 29438460) showed topical 2% gallic acid matched hydroquinone for melasma treatment, while a 2021 study (PMID: 34684561) demonstrated metabolic benefits in diabetes patients. A meta-analysis (PMID: 33667028) of gallic acid-rich pomegranate extracts found modest [cardiovascular](/ingredients/condition/heart-health) effects. ## Historical & Cultural Context Gallic acid-rich gallnuts have been used in Traditional Chinese Medicine (wu bei zi) and Ayurveda (mayaphal) for over 2,000 years as astringents for diarrhea, dysentery, wounds, and oral ulcers. European herbalism has utilized it since the 1780s, initially for ink production and leather tanning, later extending to folk remedies for sore throats. ## Synergistic Combinations Quercetin, Piperine, Vitamin C, Green Tea Extract, Resveratrol ## Frequently Asked Questions ### What foods contain gallic acid naturally? Gallic acid is abundant in green tea (up to 4.6 mg/g), red wine grapes, pomegranates, and oak-aged wines. Tea leaves and grape skins contain the highest concentrations, with brewing or fermentation increasing bioavailability. ### How much gallic acid should I take daily? Clinical studies have used doses ranging from 500-1000 mg daily for metabolic benefits. For topical melasma treatment, 2% concentration creams applied twice daily showed efficacy. No established recommended daily intake exists. ### Can gallic acid help with diabetes management? Yes, clinical evidence shows gallic acid supplementation reduced fasting blood glucose by 12.5 mg/dL and HbA1c by 0.6% in type 2 diabetics. It works by enhancing insulin sensitivity and inhibiting carbohydrate-digesting enzymes. ### Does gallic acid interact with blood pressure medications? Gallic acid may enhance the effects of antihypertensive drugs due to its modest blood pressure-lowering properties (3.5 mmHg reduction). Patients on blood pressure medications should monitor levels closely and consult healthcare providers. ### Is gallic acid effective for skin pigmentation issues? Clinical research demonstrates that 2% gallic acid cream reduced melasma severity by 32% over 12 weeks. It works by inhibiting tyrosinase enzyme activity, which controls melanin production in skin cells. ### Is gallic acid safe during pregnancy and breastfeeding? There is insufficient clinical evidence to establish the safety of gallic acid supplementation during pregnancy and breastfeeding, so it is prudent to avoid supplemental doses during these periods. While gallic acid occurs naturally in foods like tea and berries, concentrated supplement forms have not been adequately studied in pregnant or nursing populations. Consult with a healthcare provider before use if you are pregnant, planning pregnancy, or breastfeeding. ### What is the difference between gallic acid from tea extract versus grape seed extract sources? Both tea and grape seed extracts contain gallic acid, but tea extracts typically provide higher concentrations of gallic acid alongside other polyphenols like catechins, while grape seed extracts deliver gallic acid with proanthocyanidins and resveratrol. Tea-derived sources may have stronger antioxidant synergy due to the catechin profile, whereas grape seed extracts are often marketed for cardiovascular benefits from their distinct polyphenol composition. The choice depends on whether you seek the combined benefits of catechins or proanthocyanidins alongside gallic acid. ### Does gallic acid bioavailability improve when taken with food or on an empty stomach? Gallic acid absorption is enhanced when consumed with food, as dietary fats and other polyphenols can improve its intestinal uptake and reduce degradation by stomach acid. Taking gallic acid-containing supplements or extracts with a meal—particularly one containing fat—may optimize bioavailability compared to fasting consumption. However, individual absorption varies based on gut microbiota composition and overall digestive health. --- *Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com* *License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*