What is a "detox" and is it real?

In medical terminology, "detoxification" refers to two things: (1) The physiological process of metabolising and excreting endogenous waste products and exogenous toxins — performed continuously by the liver, kidneys and lungs; (2) Medical management of substance withdrawal (alcohol detox, opioid detox). In commercial marketing: "detox" refers to the claim that commercial products (juice cleanses, supplements, colonic irrigation) remove accumulated toxins from the body. This commercial use of "detox" does not correspond to a recognised medical condition or a scientifically validated process. The liver does not "get full" of toxins requiring commercial cleansing — it continuously metabolises and excretes toxins as designed by evolution.

Can diet change blood pH?

No — blood pH is one of the most tightly regulated values in human physiology. Normal blood pH is 7.35-7.45; a change of 0.1 units causes clinical symptoms; a change of 0.3-0.4 units is life-threatening. The kidneys and lungs continuously adjust acid-base balance to maintain this range regardless of what you eat. What does change with diet: urine pH — the kidneys excrete acid or base to maintain blood pH, so urine becomes more or less acidic depending on dietary load. The alkaline diet proponents measure urine pH (which does change), but this does not reflect blood pH. Eating a glass of lemon juice (acidic) does not make blood acidic — the kidneys simply excrete more acid in urine, normalising blood pH within minutes.

Should I do a juice cleanse?

There is no evidence that a juice cleanse offers any health benefit beyond the effects of caloric restriction. What happens during a 3-day juice cleanse: any weight lost is primarily water (due to glycogen depletion and reduced dietary sodium) and will return when normal eating resumes; the liver continues performing its normal detoxification functions (not enhanced by juicing); fibre is removed from vegetables and fruits (potentially reducing microbiome benefit); fructose is concentrated; no specific toxins are removed. Risks: high sugar from concentrated fruit juice; potential oxalate nephropathy from very high kale/spinach juice consumption. If you want to eat more vegetables and fruit: eat them whole, with their fibre. The evidence-based alternative to a "cleanse" is simply a Mediterranean diet.

Is activated charcoal food safe?

Activated charcoal in food and drink (charcoal bread, black latte, "detox" smoothies) is unnecessary at best and potentially harmful. Emergency medical use of activated charcoal: given within 1-2 hours of oral toxin ingestion, it can bind toxins in the gut before absorption — a genuine emergency medicine tool for poisoning. As a routine food ingredient: activated charcoal adsorbs non-selectively, meaning it binds to: medications you are taking (oral contraceptives — reduced efficacy; warfarin — reduced anticoagulation; antiepileptics — reduced seizure protection; antibiotics; any oral medication taken within several hours); beneficial nutrients and phytochemicals. If you are taking any regular medication, consuming activated charcoal food products is potentially dangerous. If not on medication, it provides no meaningful "detox" benefit.

Why do the claims persist despite the evidence?

Several factors sustain detox and alkaline diet claims despite scientific refutation: Survivorship bias: people feel better after a 3-day juice cleanse (because they've stopped eating processed food, alcohol, and are eating more vegetables) and attribute this to "detoxification" rather than improved diet quality and caloric restriction. Plausible-sounding mechanism: "toxins" and "acid" sound scientific — the mechanisms sound logical even if they are incorrect. Regulatory gap: "supports natural detoxification" can be claimed on supplements without evidence (DSHEA in the USA; similar loopholes elsewhere). Financial incentive: the global detox market exceeds $100 billion annually. Limited consumer chemistry knowledge: most people cannot evaluate the Avogadro-scale impossibilities of "memory water" or the renal physiology of pH homeostasis.

How does GMJ News cover detox and alkaline diet?

GMJ News covers liver CYP450 physiology (the real detox system), blood pH regulation (why diet cannot change it), the Worman liver flush stone analysis, activated charcoal misuse, colonic irrigation harms, juice cleanse evidence (none), what genuinely supports liver health (alcohol avoidance, healthy weight, HBV/HCV treatment), the EU regulatory status of "detox" claims, and the legitimate value of vegetables and fruit (the right benefits from the wrong mechanism). GMJ position: the body has a sophisticated, effective detoxification system; commercial detox products do not enhance it; vegetables and fruit are genuinely health-promoting — but for reasons of fibre, micronutrients and phytochemicals, not "alkalinity" or "detoxification."

Home › Topics › Detox & Alkaline Diet — The Science

Detox & Alkaline Diet — The Science

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

The “detox” and “alkaline diet” movements — generating billions in annual revenue from juice cleanses, activated charcoal drinks, alkaline water, colonic irrigation and liver-cleansing protocols — are built on two fundamental scientific misunderstandings: (1) the human liver, kidneys and lungs continuously perform detoxification as their primary physiological function, and no commercial product meaningfully augments this process in a healthy person; and (2) blood pH is tightly regulated at 7.35-7.45 by the kidneys and lungs regardless of diet — eating “alkaline” foods cannot change blood pH without inducing life-threatening alkalosis — though urine pH does change with diet, which proponents confuse with blood pH (WHO). No peer-reviewed randomised controlled trial has demonstrated that any commercial detox product, juice cleanse or alkaline diet protocol removes specific toxins, improves liver function or prevents cancer beyond the well-established benefits of a varied diet rich in vegetables, fruits and whole foods.

Key messages

The liver IS the detox system — and it runs 24/7

The human body has a sophisticated, continuous detoxification system: the liver (cytochrome P450 enzymes metabolise drugs, alcohol, environmental toxins, metabolic waste products); kidneys (filter ~180 litres of blood daily, excreting waste in urine); lungs (expired CO₂ and volatile organic compounds); skin (sweating excretes trace toxins). Commercial "detox" products do not enhance these physiological processes in people with healthy liver and kidney function. The concept of "toxin accumulation" requiring commercial detoxification is not a recognised medical condition.

Blood pH does not change with diet — urine pH does

Blood pH is tightly regulated at 7.35-7.45 by three systems: lung (CO₂ excretion — respiratory alkalosis or acidosis); kidney (bicarbonate reabsorption and acid excretion); chemical buffers (bicarbonate/carbonic acid, haemoglobin, phosphate). A change of 0.1 pH units in blood is a medical emergency (acidosis or alkalosis). Eating "alkaline" foods cannot measurably change blood pH — the kidneys simply excrete more acid or base to maintain the narrow range. Urine pH does change (and is measurable) — which is what alkaline diet proponents measure, and confuse with blood pH.

The "liver cleanse" stones are not gallstones

A popular "liver flush" protocol (olive oil + lemon juice + Epsom salts) is claimed to expel gallstones visible in the toilet. Peter Worman et al. (2005, Lancet) chemically analysed the "stones" produced after such protocols: they are saponified oil-bile complexes formed when olive oil emulsifies with intestinal Epsom salts — not gallstones. Genuine gallstones (cholesterol or pigment) require lithotripsy, ursodeoxycholic acid or cholecystectomy. No liver flush or cleanse protocol has been shown to remove gallstones from the gallbladder in any clinical study.

Activated charcoal in food and drinks — misuse of a medical tool

Activated charcoal is a genuine emergency medicine tool — given within 1-2 hours of oral toxin ingestion, it adsorbs toxins in the gastrointestinal tract (used in emergency departments for drug overdoses). As a routine food or drink ingredient (black latte, charcoal bread, "detox" smoothies): it adsorbs everything non-selectively — including medications (reduces absorption of oral contraceptives, anticoagulants, antiepileptics, antibiotics), nutrients and beneficial phytochemicals. It should not be taken routinely, and especially not with medications.

Colonic irrigation — not evidence-based and potentially harmful

Colonic irrigation (colon hydrotherapy) involves flushing large volumes of water through the colon. Claimed benefits: removing "toxins", waste build-up, improving health. Evidence: no controlled clinical trial supports health benefits. Potential harms: electrolyte disturbances (hyponatraemia — dilutional); bowel perforation (case reports); removal of beneficial microbiota; infection (from poorly sterilised equipment). The colon is not a "sewer" requiring cleaning — it is a microbiome habitat and fluid absorption organ. The medical indication for bowel cleansing (before colonoscopy or surgery) uses specific regulated preparations, not spa-style irrigation.

Vegetables and fruit are genuinely healthy — but not because of "detox"

The confusion is real: vegetables, fruits and whole grains are genuinely health-promoting — but their benefits come from fibre (microbiome, satiety, reduced colorectal cancer risk), vitamins, minerals, antioxidants (which reduce oxidative stress), phytochemicals (anti-inflammatory) and displacement of less healthy foods. These effects are well-evidenced. Attributing the same benefits to "alkalinity" or "detoxification" is a misattribution — the science is real, but the mechanism is wrong.

Key statistics

180 litres

of blood filtered by the kidneys daily — continuous "detoxification"

Renal physiology

7.35-7.45

blood pH range — tightly regulated regardless of diet

Physiology

2005 Lancet

Peter Worman — "liver flush stones" are saponified oil, not gallstones

Lancet 2005

1-2 hours

window for activated charcoal effectiveness in genuine poisoning (emergency use)

Emergency medicine

0 RCTs

no randomised controlled trial demonstrates clinical benefit of commercial detox products

WHO/Evidence

$100B+

global detox and cleanse supplement market — evidence: essentially none

Market research

Real detoxification — how the body actually removes toxins (physiology)

Source: Human physiology. The liver, kidneys, lungs and gut are the body's continuous, regulated detoxification systems.

Glossary of key terms

Cytochrome P450 (CYP450) enzyme system
BiochemistryA superfamily of hepatic enzymes (and in the gut, kidneys and other tissues) that metabolise: drugs (Phase I metabolism — oxidation, reduction, hydrolysis; most drugs are CYP3A4 substrates); endogenous compounds (steroids, bile acids, fatty acids); environmental chemicals (polyaromatic hydrocarbons, pesticides, carcinogens — converting them to more water-soluble metabolites for urinary or biliary excretion). The liver runs this "detoxification" machinery continuously. Supporting liver health (avoiding excess alcohol, maintaining healthy weight, not taking hepatotoxic substances) supports CYP function. No commercial supplement has been shown to augment CYP450 capacity beyond what a healthy liver provides.

Blood pH regulation
PhysiologyBlood pH (7.35-7.45) is maintained by three homeostatic systems: (1) Respiratory buffer: increased CO₂ → reduced pH → faster breathing → more CO₂ exhaled → pH normalises (seconds-to-minutes response); (2) Renal regulation: kidneys increase or decrease bicarbonate reabsorption and H⁺ excretion (hours-to-days response — the primary long-term regulator); (3) Chemical buffers: the bicarbonate/carbonic acid buffer system (HCO₃⁻/H₂CO₃) is the primary extracellular buffer. The alkaline diet claim: eating "alkaline" vegetables raises blood pH. The reality: the kidneys simply excrete more bicarbonate to counteract any dietary alkaline load — blood pH is unchanged. Urine pH does change — but that is the kidneys doing their job, not a health intervention.

The alkaline diet — historical note
History/ScienceThe alkaline diet theory holds that different foods produce "acid ash" or "alkaline ash" after metabolism — and that eating more "alkaline" foods reduces cancer risk, osteoporosis and other conditions by reducing body "acidity." The chemistry is partly correct: some foods produce more acidic urinary metabolites (meat, dairy) or more alkaline metabolites (fruits, vegetables). The extrapolation to blood pH and disease prevention is not — blood pH is regulated independently of dietary ash. The alkaline diet's health claims (cancer prevention, osteoporosis prevention) are not supported by clinical evidence beyond what is explained by higher vegetable and fruit intake per se.

Detox supplements — regulatory status
FDA/MHRAIn the USA: dietary supplements (including detox products) do not require pre-market approval of efficacy or safety (DSHEA 1994). Companies cannot claim to "diagnose, cure, treat or prevent" disease but can make "structure/function" claims ("supports liver health", "promotes natural detoxification"). These claims require no proof. In the UK: the MHRA applies food supplement regulations that prohibit health claims not permitted under EU Regulation 1924/2006 — "detox" is not an approved health claim in the EU, meaning products cannot legally make this claim in the EU. Despite this, the marketing language is widely used.

Juice cleanses — what the evidence actually shows
ResearchA 2017 systematic review of juice-based "detox" and "cleanse" diets (covering approximately 20 studies): no controlled clinical trials. Small uncontrolled studies report: transient weight loss (water weight and caloric restriction effect — not fat loss); changes in inflammatory markers inconsistent across studies; no evidence of enhanced toxin excretion; no sustained metabolic benefit. Risks: high sugar content from juicing (removes fibre, concentrates fructose); oxalate nephropathy reported from green juice overconsumption (kale/spinach oxalate + depleted calcium → kidney stones). Any weight loss during a juice fast is attributable to caloric restriction and dehydration — not "detoxification."

What actually supports liver health?
WHO/HepatologyEvidence-based liver support: Avoid excess alcohol (the liver's primary metabolic challenge in HICs — alcohol-related liver disease is entirely preventable). Healthy weight (NAFLD — non-alcoholic fatty liver disease — is caused by obesity; weight loss reverses it). Avoid hepatotoxic substances: high-dose acetaminophen/paracetamol; herbal hepatotoxins (kava, pyrrolizidine alkaloids, high-dose green tea extract). Treat hepatitis B and C (effective antivirals exist). Adequate protein (liver enzyme production requires amino acids). No commercial "liver cleanse" product has demonstrated hepatoprotective benefit in controlled clinical trials.