Are Juice Cleanses Healthy? What Science Says
Juice cleanses promise a lot: flush out toxins, reset your digestion, and drop pounds in just a few days. It sounds appealing — but what does the science actually say? This article looks at what “detox” really means in the body, what juice cleanses are, and what the evidence shows about their benefits and risks.
What Does “Detox” Actually Mean in Your Body?
The word “toxin” is used loosely in wellness marketing, but your body already has dedicated systems for handling waste products:
- The liver processes many substances — from natural metabolic byproducts to alcohol and medications — converting them into forms the body can eliminate.
- The kidneys filter the blood and remove water-soluble waste through urine.
- The lungs remove gases such as carbon dioxide with every breath you exhale.
- The gut moves undigested material and some waste products out through stool.
These systems run continuously, whether or not you drink juice. According to the U.S. National Center for Complementary and Integrative Health (NCCIH), part of the National Institutes of Health, there is little evidence to support the use of juice cleanses for eliminating toxins from the body, and there have been no studies on the long-term effects of “detoxification” programs. The NCCIH also notes that some “detoxification” or “cleansing” programs can be unsafe and falsely advertised.
In short: no food or juice has been shown to “flush toxins” beyond what your liver, kidneys, lungs, and gut already do. A healthy body detoxes itself every day.
What Is a Juice Cleanse?
A juice cleanse (or “juice fast”) is a short-term diet in which a person drinks only fruit and vegetable juices — sometimes for one day, sometimes for a week or longer — while eating little or no solid food. They are marketed as a way to “cleanse” the body, rest the digestive system, and lose weight quickly. Common ingredients include apple, orange, carrot, celery, cucumber, ginger, lemon, and leafy greens such as spinach or kale. Juicing removes most of the fiber from fruits and vegetables, leaving behind mostly water, sugars, and some vitamins and minerals.
What Does the Evidence Say About Benefits?
Possible short-term effects
- Some people feel a temporary sense of lightness or reduced bloating during a cleanse, which may partly come from eating less heavy, salty, or processed food for a few days — not necessarily from the juice itself.
- Drinking more fruit and vegetable juice can briefly increase intake of certain vitamins and fluids, but whole fruits and vegetables provide the same nutrients PLUS fiber, which juice largely lacks.
What the evidence does NOT support
- “Flushing toxins”: There is no good evidence that juice cleanses remove toxins that your organs could not remove on their own.
- Lasting weight loss: The NCCIH notes that diets that severely restrict calories or the types of food you eat usually do not lead to lasting weight loss and may not provide all the nutrients you need. Weight lost during a cleanse often returns once normal eating resumes, because much of the initial loss is water and glycogen, not fat.
- No proven long-term health benefits: Because no long-term studies exist on detoxification programs, claims about lasting improvements are not backed by evidence.
A 2015 critical review of detox diets in the Journal of Human Nutrition and Dietetics found that the clinical evidence for detox diets is limited and that more rigorous research would be needed to support any of the claimed benefits.
Risks and Downsides of Juice Cleanses
Juice cleanses are not risk-free. Reported and plausible downsides include:
- Calorie and nutrient deficits. Juice-only diets are very low in protein, essential fats, and some micronutrients. Very-low-calorie intake for multiple days can leave you fatigued and may cause the body to break down muscle tissue along with fat.
- Blood sugar spikes. Without fiber, protein, or fat to slow absorption, the natural sugars in fruit and vegetable juices can cause rapid rises — and subsequent drops — in blood sugar. This is a particular concern for people with diabetes or insulin resistance.
- Gastrointestinal issues. Some people report nausea, diarrhea, cramps, or general GI upset during cleanses.
- Electrolyte concerns. Diarrhea, low mineral intake, and very low calorie intake can disturb the body’s fluid and electrolyte balance in susceptible people.
- Gut microbiome disruption. A small 2025 study published in Nutrients found that just three days of a juice-only diet shifted gut and oral bacteria toward species associated with inflammation and gut permeability. The study was small, so results are preliminary.
- Food safety. The NCCIH warns that some juices used in detoxes and cleanses have not been pasteurized or treated to kill harmful bacteria, and can make people sick — serious in children, older adults, and people with weakened immune systems.
- Kidney stone risk from oxalate. Some juices are made from high-oxalate foods such as spinach and beets. People susceptible to kidney stones should limit high-oxalate foods.
The Rebound Problem: Weight Regain After Cleansing
Much of the weight lost during a juice cleanse is water weight and glycogen (the stored form of carbohydrate in muscles and liver), not body fat. Once you resume eating normally, that weight typically returns quickly. When calories and protein are very low for several days, the body may break down some muscle tissue for energy. Sustainable weight management comes from balanced eating and regular activity over time, not from short restrictive episodes.
Who Should NOT Do a Juice Cleanse or Fast
Juice cleanses and fasting are not appropriate for everyone. The following groups should avoid them unless a qualified healthcare professional advises otherwise: children and teenagers; people who are pregnant or breastfeeding; people with diabetes or blood sugar disorders; people with kidney disease; people with eating disorders or a history of disordered eating; people taking medications affected by potassium or blood sugar levels; older adults and anyone with a weakened immune system (unpasteurized juice risk).
Better Ways to Support Your Body’s Natural Detox Systems
- Eat whole fruits and vegetables daily — with their fiber intact.
- Drink enough water throughout the day.
- Limit alcohol, which adds work for the liver.
- Get regular physical activity and enough sleep.
- Don’t smoke.
Focus on consistent habits: a balanced diet rich in whole fruits and vegetables, adequate water, regular exercise, enough sleep, and limiting alcohol. If you want structured help, consider consulting a registered dietitian.
The Bottom Line
Juice cleanses are popular, but the science does not support their main claims. Your body already has effective detox systems — the liver, kidneys, lungs, and gut — and no juice has been shown to improve on them. Short-term cleanses may cause temporary water-weight loss, but they carry real risks, from blood sugar swings to nutrient deficits, and any weight lost tends to come back.
Disclaimer: This article is for general informational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before making significant changes to your diet, especially if you have a medical condition, take medications, or are pregnant or breastfeeding.
References
- National Center for Complementary and Integrative Health (NCCIH). “‘Detoxes’ and ‘Cleanses’: What You Need To Know.” https://www.nccih.nih.gov/health/detoxes-and-cleanses-what-you-need-to-know
- Klein, A. V., & Kiat, H. (2015). Detox diets for toxin elimination and weight management: A critical review of the evidence. Journal of Human Nutrition and Dietetics, 28(6), 675–686. https://doi.org/10.1111/jhn.12286
- Ring, M., et al. (2025). Juice-only and juice-plus-food dietary interventions and gut/oral microbiome changes. Nutrients, 17(3), 458. https://doi.org/10.3390/nu17030458
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