# Thymohydroquinone

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/thymohydroquinone
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-02
**Evidence Score:** 2 / 10
**Category:** Compound
**Also Known As:** 2,5-dihydroxy-p-cymene, THQ, Monoterpene phenol C₁₀H₁₄O₂, Dihydroxycymene, Thyme hydroquinone, 2,5-dihydroxy-4-isopropyltoluene

## Overview

Thymohydroquinone is a naturally occurring monoterpenoid quinone derived primarily from Nigella sativa (black seed) that exerts its effects through inhibition of [acetylcholine](/ingredients/condition/cognitive)sterase, [antioxidant](/ingredients/condition/antioxidant) radical scavenging, and disruption of microbial cell membrane integrity. Current evidence is largely preclinical, with in vitro and animal studies demonstrating [antimicrobial](/ingredients/condition/immune-support), [anti-inflammatory](/ingredients/condition/inflammation), and potential anticancer properties.

## Health Benefits

• Antioxidant properties that protect against [oxidative stress](/ingredients/condition/antioxidant) (preclinical evidence only)
• [Anti-inflammatory](/ingredients/condition/inflammation) effects demonstrated in laboratory studies (preclinical evidence only)
• [Antimicrobial](/ingredients/condition/immune-support) activity shown in vitro (preclinical evidence only)
• Cancer cell inhibition with IC50 values of 2.4-15.9 μM (in vitro studies only, no human trials)
• Potential enzyme modulation targeting oxidoreductases and matrix metalloproteinases (mechanism studies only)

## Mechanism of Action

Thymohydroquinone acts as a potent inhibitor of [acetylcholine](/ingredients/condition/cognitive)sterase (AChE), preventing the breakdown of acetylcholine and thereby modulating cholinergic neurotransmission. It also scavenges [reactive oxygen species](/ingredients/condition/antioxidant) (ROS) by donating hydrogen atoms through its hydroquinone moiety, reducing oxidative damage to lipids, proteins, and DNA. Additionally, it suppresses pro-inflammatory mediators by downregulating NF-κB signaling and inhibiting cyclooxygenase (COX) enzyme activity, limiting [prostaglandin](/ingredients/condition/inflammation) synthesis.

## Clinical Summary

No peer-reviewed human clinical trials have been conducted specifically on isolated thymohydroquinone as of the current literature. Preclinical in vitro studies have reported cancer cell inhibition with IC50 values in the low micromolar range (approximately 2.4–10 µM) against various tumor cell lines, including breast and colon cancer cells. Animal studies using rodent models have demonstrated [anti-inflammatory](/ingredients/condition/inflammation) and [neuroprotective effect](/ingredients/condition/cognitive)s at doses ranging from 10 to 100 mg/kg body weight. The overall evidence base remains at an early preclinical stage, and conclusions about human efficacy cannot be drawn without controlled clinical trials.

## Nutritional Profile

Thymohydroquinone (THQ) is a pure bioactive compound (C10H14O2, molecular weight 166.22 g/mol), not a whole food ingredient, and therefore has no conventional macronutrient or micronutrient profile. It is a monoterpenoid hydroquinone derivative naturally occurring in Nigella sativa (black seed) essential oil at concentrations of approximately 0.2–0.5% of total oil composition, alongside thymoquinone and thymohydroquinone dimethyl ether. As an isolated compound: no protein, carbohydrate, fiber, or fat content is applicable. Bioactive profile centers on its phenolic hydroquinone core structure, which confers electron-donating [antioxidant](/ingredients/condition/antioxidant) capacity. LogP (lipophilicity) is estimated at approximately 2.8–3.2, suggesting moderate lipid solubility and potential for passive membrane permeability. Oral bioavailability data in humans is not established; preclinical studies suggest hepatic first-pass [metabolism](/ingredients/condition/weight-management) may produce conjugated sulfate and glucuronide metabolites. In Nigella sativa oil as a source matrix, THQ co-occurs with thymoquinone (~0.5–1.5% of oil), carvacrol, and p-cymene. No clinically validated dosing concentration or recommended intake level has been established for isolated THQ in humans.

## Dosage & Preparation

No clinically studied dosage ranges are available as human trials have not been conducted. Commercial forms show 99-99.6% purity in solid preparations, but therapeutic doses have not been established. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Thymohydroquinone has not been evaluated in formal human safety or toxicology trials as an isolated compound, making definitive side effect profiles difficult to establish. Because it inhibits [acetylcholine](/ingredients/condition/cognitive)sterase, concurrent use with cholinesterase inhibitor medications such as donepezil or rivastigmine may produce additive cholinergic effects, including nausea, bradycardia, and excessive secretions. Its presence in Nigella sativa oil at typical dietary concentrations is generally considered safe, but concentrated supplemental extracts carry unknown risk, particularly for pregnant or breastfeeding individuals who should avoid isolated thymohydroquinone supplements until safety data exist. Individuals on anticoagulant or antiplatelet therapy should exercise caution, as Nigella sativa compounds have demonstrated platelet aggregation inhibition in preclinical models.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses have been conducted on thymohydroquinone. All available evidence comes from preclinical studies including in vitro cancer inhibition research (Cancer Res. 2002; Cancer Cell 2004; Biochem. Pharmacol. 2010), though these citations lack PubMed PMIDs and involve only laboratory or animal models.

## Historical & Cultural Context

No traditional or historical medicinal uses specific to thymohydroquinone are documented. While related compound thymoquinone from similar plants has traditional uses as an antihypertensive and digestive aid (PubMed PMID: 37605475), this does not apply directly to thymohydroquinone.

## Synergistic Combinations

Thymol, carvacrol, rosmarinic acid, quercetin, vitamin E

## Frequently Asked Questions

### What is thymohydroquinone and where does it come from?

Thymohydroquinone is a monoterpenoid quinone naturally found in Nigella sativa (black seed) oil, where it occurs alongside related compounds thymoquinone and thymol. It is produced biosynthetically from thymoquinone through reduction reactions and represents one of the key bioactive constituents responsible for black seed's pharmacological properties. Trace amounts also appear in certain thyme (Thymus vulgaris) species.

### Does thymohydroquinone have anticancer properties?

In vitro studies have reported that thymohydroquinone inhibits the proliferation of cancer cell lines, including breast, colon, and lung cancer cells, with IC50 values in the range of approximately 2.4–10 µM depending on the cell line tested. These effects are thought to involve induction of apoptosis and inhibition of cell cycle progression. However, no human clinical trials have confirmed anticancer effects, and in vitro results do not reliably predict outcomes in humans.

### Can thymohydroquinone improve memory or brain function?

Thymohydroquinone's ability to inhibit acetylcholinesterase (AChE) has generated interest in its potential neuroprotective and cognitive-enhancing properties, as AChE inhibition increases acetylcholine availability in synaptic clefts—the same mechanism used by Alzheimer's drugs like donepezil. Rodent studies have shown improvements in memory task performance following black seed extract administration, though effects from isolated thymohydroquinone specifically in humans remain untested. Any cognitive benefit in people is currently speculative.

### How does thymohydroquinone compare to thymoquinone?

Thymoquinone is the most abundant and studied bioactive quinone in Nigella sativa, while thymohydroquinone is its reduced metabolite formed by the addition of two hydrogen atoms. Thymohydroquinone demonstrates comparable or superior acetylcholinesterase inhibition relative to thymoquinone in some assays, whereas thymoquinone has a larger body of preclinical evidence for anti-inflammatory and anticancer effects. Both compounds share antioxidant mechanisms but differ in their chemical stability and bioavailability profiles.

### What is the typical dosage of thymohydroquinone in supplements?

There is no established human dosage for isolated thymohydroquinone, as no clinical trials have defined safe or effective dose ranges. In animal studies, biologically active doses of black seed extracts containing thymohydroquinone have ranged from 10 to 100 mg/kg body weight, which does not translate directly to human supplementation guidelines. Consumers currently encounter thymohydroquinone most often as a minor constituent within whole Nigella sativa oil or black seed extract products, typically standardized to thymoquinone content rather than thymohydroquinone specifically.

### Is thymohydroquinone safe to take with common medications?

There are currently no documented drug interactions with thymohydroquinone in human studies, as clinical research on this compound is extremely limited. However, because thymohydroquinone may have enzyme-modulating properties targeting oxidoreductase pathways, it could theoretically interact with medications metabolized by similar pathways. Anyone taking prescription medications should consult their healthcare provider before adding thymohydroquinone supplements to ensure safety and prevent potential interactions.

### What does the current research evidence show about thymohydroquinone's effectiveness in humans?

Most evidence for thymohydroquinone comes from laboratory and animal studies only—there are no published human clinical trials demonstrating efficacy or safety. While in vitro studies show promising antioxidant, anti-inflammatory, and antimicrobial properties, these preclinical results cannot be reliably translated to human health outcomes without controlled clinical research. Consumers should be cautious about health claims regarding thymohydroquinone until human trials provide concrete evidence of benefit.

### Who should avoid taking thymohydroquinone supplements?

Thymohydroquinone should be avoided by pregnant and nursing women due to lack of safety data in these populations. Individuals with oxidative stress-sensitive conditions, those taking immunosuppressant or antioxidant medications, and people with enzyme deficiencies affecting oxidoreductase function should consult a healthcare provider before use. Children should not take thymohydroquinone supplements without medical supervision, as safety and appropriate dosing have not been established in pediatric populations.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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