Below is a solid and serious list of major detoxification-related chemicals, enzymes, and transporters, with body sources and when they matter most.
In biochemistry, detoxification mainly means:
phase I biotransformation,
phase II conjugation, and
phase III transport/excretion.
1. Glutathione (GSH)
- Body source: Synthesized in most cells, especially liver
- When it matters: Major antioxidant and conjugating molecule; crucial for oxidative stress, drug metabolism, and toxin handling (e.g., acetaminophen)
2. Glutathione S-transferases (GSTs)
- Body source: Enzymes highly expressed in liver, also gut and other tissues
- When it matters: Conjugate electrophilic toxins to glutathione during phase II detoxification
3. Glutathione reductase
- Body source: Present in most tissues
- When it matters: Regenerates reduced glutathione; important when oxidative burden is high
4. N-acetylcysteine (NAC)
- Body source: Not made in large amounts endogenously; used as a precursor supplement
- When it matters: Supports glutathione synthesis; clinically relevant in acetaminophen toxicity and low glutathione states
5. Cysteine
- Body source: From diet and from methionine via transsulfuration
- When it matters: Rate-limiting amino acid for glutathione synthesis under many conditions
6. Methionine
- Body source: Essential amino acid from diet
- When it matters: Supports methylation and sulfur amino acid metabolism
7. S-adenosylmethionine (SAMe)
- Body source: Produced from methionine in cells
- When it matters: Universal methyl donor; important for methylation-dependent detox reactions
8. Folate / 5-methyltetrahydrofolate (5-MTHF)
- Body source: Dietary folate, converted to active forms
- When it matters: One-carbon metabolism and methylation support
9. Vitamin B12
- Body source: Dietary intake, absorbed in ileum with intrinsic factor
- When it matters: Works with folate in methylation and homocysteine metabolism
10. Vitamin B6 (pyridoxal-5-phosphate, P5P)
- Body source: Dietary intake
- When it matters: Needed for transsulfuration and amino acid metabolism
11. UDP-glucuronic acid
- Body source: Made intracellularly from glucose
- When it matters: Donor substrate for glucuronidation
12. UDP-glucuronosyltransferases (UGTs)
- Body source: Enzymes concentrated in liver and intestine
- When it matters: Major phase II enzymes that make compounds more water-soluble
13. Sulfate
- Body source: Derived from diet and sulfur amino acid metabolism
- When it matters: Donor for sulfation reactions
14. Sulfotransferases (SULTs)
- Body source: Liver and many extrahepatic tissues
- When it matters: Important for detoxifying hormones, drugs, and xenobiotics
15. Cytochrome P450 enzymes (CYPs)
- Body source: Mainly liver, also intestine and other tissues
- When it matters: Major phase I oxidation system for drugs and toxins
16. Cytochrome P450 reductase
- Body source: Expressed with CYP systems in microsomes
- When it matters: Transfers electrons to CYP enzymes for oxidation reactions
17. NADPH
- Body source: Generated by pentose phosphate pathway and other metabolism
- When it matters: Required for CYP function and antioxidant recycling
18. Flavin adenine dinucleotide (FAD)
- Body source: Derived from riboflavin (B2)
- When it matters: Cofactor for redox enzymes, including glutathione reductase
19. Flavin mononucleotide (FMN)
- Body source: Also derived from riboflavin (B2)
- When it matters: Important in electron transfer systems
20. Taurine
- Body source: From cysteine metabolism and diet
- When it matters: Conjugation of bile acids; supports bile flow and elimination
21. Glycine
- Body source: Dietary and endogenous synthesis
- When it matters: Amino acid conjugation and glutathione synthesis
22. Glycine N-acyltransferase (GLYAT)
- Body source: Liver mitochondrial enzyme
- When it matters: Conjugates organic acids for urinary excretion
23. Epoxide hydrolase
- Body source: Liver and other tissues
- When it matters: Converts reactive epoxides to less reactive diols
24. Carboxylesterases
- Body source: Liver, intestine
- When it matters: Hydrolyze ester-containing xenobiotics and prodrugs
25. NQO1 (NAD(P)H:quinone oxidoreductase 1)
- Body source: Widely expressed, induced by oxidative stress response
- When it matters: Detoxifies quinones and reduces redox cycling
26. Heme oxygenase-1 (HO-1)
- Body source: Inducible in many tissues
- When it matters: Stress-response enzyme that degrades heme under oxidative stress
27. Superoxide dismutase (SOD)
- Body source: Cytosol, mitochondria, extracellular space
- When it matters: Removes superoxide; supports detox by limiting oxidative injury
28. Catalase
- Body source: Mainly peroxisomes
- When it matters: Breaks down hydrogen peroxide
29. Thioredoxin / Thioredoxin reductase
- Body source: Present in most cells
- When it matters: Maintains redox balance and supports antioxidant defenses
30. ABCB1 (P-glycoprotein)
- Body source: Intestine, liver canalicular membrane, kidney, blood-brain barrier
- When it matters: Pumps xenobiotics out of cells; key phase III transporter
31. ABCC2 (MRP2)
- Body source: Liver canalicular membrane, intestine
- When it matters: Exports glucuronide, glutathione, and sulfate conjugates into bile
32. ABCG2 (BCRP)
- Body source: Intestine, liver, placenta, blood-brain barrier
- When it matters: Efflux of many xenobiotics and metabolites
33. Organic anion transporting polypeptides (OATPs)
- Body source: Liver, intestine, other tissues
- When it matters: Uptake transporters that move compounds into hepatocytes for processing
34. Selenium
- Body source: Dietary micronutrient
- When it matters: Needed for selenoenzymes such as glutathione peroxidase
35. Zinc
- Body source: Dietary micronutrient
- When it matters: Supports many enzymes and antioxidant defenses
36. Magnesium
- Body source: Dietary mineral
- When it matters: ATP-dependent enzymatic reactions, including metabolism and conjugation
37. Molybdenum
- Body source: Dietary trace element
- When it matters: Cofactor for sulfite oxidase and other enzymes
38. Vitamin C
- Body source: Dietary vitamin
- When it matters: Antioxidant regeneration and protection from oxidative stress
39. Vitamin E
- Body source: Dietary fat-soluble vitamin
- When it matters: Protects membranes from lipid peroxidation
40. Alpha-lipoic acid
- Body source: Endogenously synthesized in small amounts
- When it matters: Redox cofactor and antioxidant support
41. Coenzyme Q10
- Body source: Endogenous synthesis and diet
- When it matters: Mitochondrial electron transport and antioxidant defense
42. Heme-containing cytochrome systems
- Body source: Liver microsomes
- When it matters: Oxidative metabolism of drugs and toxins
43. Bile acids
- Body source: Synthesized in liver from cholesterol
- When it matters: Aid excretion of lipophilic compounds via bile
44. Bile salt export pump (BSEP/ABCB11)
- Body source: Liver canalicular membrane
- When it matters: Exports bile acids into bile for elimination
45. Organic cation transporters (OCTs)
- Body source: Liver, kidney
- When it matters: Handle cationic drugs and metabolites
46. Multidrug resistance-associated proteins (MRPs)
- Body source: Liver, kidney, intestine
- When it matters: Export conjugated toxins and metabolites
47. Urea cycle enzymes
- Body source: Liver
- When it matters: Detoxifies ammonia, a major metabolic toxin
48. Ornithine
- Body source: Produced in the urea cycle
- When it matters: Central intermediate in ammonia detoxification
49. Citrulline
- Body source: Produced in the urea cycle and intestine
- When it matters: Nitrogen disposal and ammonia handling
50. Arginine
- Body source: Dietary and endogenous
- When it matters: Urea cycle substrate; supports ammonia detoxification
When these matter most, overall
They matter most during:
- Drug exposure
- Alcohol exposure
- Inflammation and oxidative stress
- Poor nutrition or deficiency states
- High toxin burden
- Liver or kidney impairment
- Fasting or malnutrition
- Acetaminophen overdose
- High xenobiotic exposure
- Increased bilirubin/bile handling demands
Full references
- Klaassen, C. D. (Ed.). (2013). Casarett & Doull’s Toxicology: The Basic Science of Poisons (8th ed.). McGraw-Hill Education.
- Nelson, D. L., & Cox, M. M. (2021). Lehninger Principles of Biochemistry (8th ed.). W. H. Freeman.
- Zanger, U. M., & Schwab, M. (2013). Cytochrome P450 enzymes in drug metabolism: Regulation of gene expression, enzyme activities, and impact of genetic variation. Pharmacology & Therapeutics, 138(1), 103–141. https://doi.org/10.1016/j.pharmthera.2012.12.007
- Guengerich, F. P. (2008). Cytochrome P450 and chemical toxicology. Chemical Research in Toxicology, 21(1), 70–83. https://doi.org/10.1021/tx700079z
- Lu, S. C. (2013). Glutathione synthesis. Biochimica et Biophysica Acta, 1830(5), 3143–3153. https://doi.org/10.1016/j.bbagen.2012.09.008
- DeLeve, L. D., & Kaplowitz, N. (2014). Glutathione metabolism and its role in hepatotoxicity. Pharmacology & Therapeutics, 109(1–2), 131–149. https://doi.org/10.1016/j.pharmthera.2005.01.010
- Tukey, R. H., & Strassburg, C. P. (2000). Human UDP-glucuronosyltransferases: Metabolism, expression, and disease. Annual Review of Pharmacology and Toxicology, 40, 581–616. https://doi.org/10.1146/annurev.pharmtox.40.1.581
- Stipanuk, M. H. (2004). Sulfate, transsulfuration, and taurine metabolism in health and disease. Advances in Experimental Medicine and Biology, 566, 87–107. https://doi.org/10.1007/0-387-26206-7_5
- Klaassen, C. D., & Aleksunes, L. M. (2010). Xenobiotic, bile acid, and cholesterol transporters: Function and regulation. Pharmacological Reviews, 62(1), 1–96. https://doi.org/10.1124/pr.109.002014
- 10.Hayes, J. D., & Dinkova-Kostova, A. T. (2014). The Nrf2 regulatory network provides an interface between redox and intermediary metabolism. Trends in Biochemical Sciences, 39(4), 199–218. https://doi.org/10.1016/j.tibs.2014.02.002