What Does a Cleanse Actually Do? An Evidence-Based Look

October 19, 2025 •

4 min read

According to the National Center for Complementary and Integrative Health, there is little high-quality evidence that cleanses and detox diets effectively remove toxins from the body. So, what does a cleanse actually do? This article dives into the science behind these popular wellness trends.

Quick Summary

Cleanses are short-term diets often involving restrictive eating or supplements, marketed to remove toxins and boost health. Scientific consensus indicates the body has its own efficient detoxification system, rendering commercial cleanses unnecessary and potentially unsafe. Any perceived benefits are typically temporary, resulting from reduced intake of processed foods and not from a 'detoxification' process.

Key Points

The body has natural detox systems: Your liver, kidneys, and other organs are already highly efficient at removing toxins, making commercial cleanses unnecessary for a healthy individual.
Cleanses offer temporary, not deep, effects: The rapid weight loss often seen on a cleanse is mostly water weight, which returns once normal eating resumes.
Risks outweigh benefits: Many cleanses are unregulated and carry risks such as dehydration, nutrient deficiencies, metabolic slowing, and potential organ damage.
Focusing on a healthy diet and lifestyle is more effective: Sustainable habits like staying hydrated, eating fiber-rich foods, and exercising are the best ways to support your body's natural detoxification.
Beware of marketing claims: Anecdotal testimonials and celebrity endorsements often overstate the benefits and downplay the risks of commercial cleanse products.
Listen to experts, not influencers: Medical professionals generally advise against cleanses, pointing to a lack of scientific evidence and potential harm.

Understanding the 'Cleanse' Concept vs. Your Body's Natural Systems

The wellness industry is rife with products promising to “detox” your body or perform a “full-body cleanse.” These programs, which can range from juice fasts to herbal supplement regimens, operate on the premise that our bodies accumulate harmful toxins that need to be flushed out. The truth is, a healthy human body possesses highly efficient and sophisticated detoxification systems that work 24/7 without special diets or supplements. Your liver, kidneys, lungs, and digestive system are constantly processing and eliminating waste and harmful substances. Cleanses, therefore, do not perform a function that your body isn't already naturally equipped to handle. Instead, what a cleanse actually does is force a temporary and often drastic change in your diet, which can lead to other, often misinterpreted, effects.

Deconstructing the Different Types of Cleanses

Cleanses and detoxes can take various forms, each with its own set of methods and risks:

Juice Cleanses: These involve consuming only fruit and vegetable juices for a set period. They are often low in protein and calories, leading to rapid, temporary weight loss that is mostly water weight. The high sugar content from fruits can also cause blood sugar spikes.
Herbal Cleanses: These utilize specific herbs, teas, or supplements intended to stimulate organs like the liver or colon. Many of these supplements are unregulated by health authorities like the FDA and can contain potentially harmful ingredients.
Colon Cleanses: Also known as colonic irrigation, this procedure involves flushing the large intestine with large amounts of fluid. The practice is based on the unproven theory of 'autointoxication' and can disrupt the natural balance of beneficial gut bacteria.
Elimination Diets: While some cleanses can be framed this way, a true elimination diet is a structured process used to identify food sensitivities, not a 'detox' tool. A cleanse's restrictive nature may temporarily reduce inflammatory symptoms, but this is a side effect of removing common irritants, not a magical purifying process.

The Real Effects of a Cleanse on Your Body

What are the actual outcomes of undertaking a cleanse? Rather than magically flushing out toxins, the effects are typically a result of the dietary changes imposed by the regimen.

Short-Term Weight Loss: Most cleanses are very low-calorie, causing the body to shed water weight and deplete glycogen stores rapidly. This leads to a quick drop on the scale that can feel motivating but is not sustainable fat loss. Once normal eating resumes, the weight almost always returns.

Reduced Cravings: By cutting out processed foods, sugar, alcohol, and caffeine, a cleanse can help break an addiction to unhealthy eating patterns. This reset can be a positive step toward a healthier lifestyle, but it's the behavior change, not the 'cleanse' itself, that deserves the credit.

Increased Nutrient Intake: If a cleanse consists of nutrient-dense liquids like vegetable juices, it may provide a short-term boost of vitamins and minerals. However, this is not a sustainable or balanced way to get nutrients and can be achieved more safely through a balanced diet.

Potential Risks and Side Effects: The downsides are significant. Many cleanses cause digestive issues like diarrhea, bloating, and cramping due to laxatives or a sudden increase in fiber. Severe caloric restriction can lead to fatigue, headaches, dizziness, and low energy. Prolonged or extreme cleanses can lead to nutrient deficiencies and, in some cases, damage to organs like the kidneys and liver.

Natural Detoxification vs. Commercial Cleanses: A Comparison


Feature	Commercial Cleanse	Natural Detoxification (Body's Process)
Method	Restrictive diets, supplements, juices, laxatives, colonics	Metabolic processes, digestion, liver and kidney filtration
Effectiveness	Not scientifically proven to remove toxins; any effects are temporary	Highly efficient; the body's primary and constant method of removing waste
Safety	Unregulated products, potential for dehydration, nutrient deficiencies, or organ damage	Safe and effective under normal health conditions.
Sustainability	Short-term fixes; often lead to 'rebound' weight gain and unhealthy eating cycles	Long-term solution through a balanced diet and healthy habits
Nutritional Value	Often nutritionally unbalanced, lacking essential macronutrients like protein	Relies on a balanced intake of nutrients to function properly
Evidence	Largely anecdotal, driven by marketing hype	Backed by extensive scientific and medical understanding

How to Support Your Body's Natural Detoxification

Instead of opting for a costly and potentially dangerous commercial cleanse, you can support your body's built-in detox systems through simple, sustainable lifestyle choices. These methods are backed by science and promote genuine, long-term wellness.

Stay Hydrated: Drinking plenty of water helps your kidneys filter and eliminate waste from your blood through urine.
Eat a Fiber-Rich Diet: Fiber from fruits, vegetables, and whole grains aids digestion and regular bowel movements, helping the digestive system remove waste.
Limit Processed Foods and Sugar: Reducing your intake of inflammatory foods and excessive sugar can significantly lessen the burden on your body's organs.
Get Regular Exercise: Physical activity improves circulation and can help release small amounts of toxins through sweat.
Ensure Adequate Sleep: Your body repairs and regenerates itself while you sleep, which is crucial for overall health and organ function.

Conclusion

Ultimately, the idea that a commercial cleanse can or will 'detoxify' your body is a pervasive myth. Your body is a finely tuned machine, equipped with a comprehensive system for removing waste and toxins. What a cleanse actually does is not a magical cleansing but rather a restrictive diet that may have temporary, and often misleading, effects. For sustainable health and true wellness, prioritizing a balanced diet, adequate hydration, regular exercise, and sufficient sleep is a far safer and more effective strategy than relying on unproven and potentially risky cleanse products. For more information on evidence-based health practices, you can consult authoritative sources like the National Institutes of Health.

Frequently Asked Questions

No, there is little scientific evidence to support the claim that commercial cleanses or detox diets effectively remove toxins from your body. A healthy body has its own organs, like the liver and kidneys, that do this naturally and constantly.

A cleanse may cause temporary weight loss, but it is typically water weight and not sustainable fat loss. Most people regain the weight shortly after returning to their regular diet, and the restrictive nature can even slow metabolism.

Juice cleanses can provide a quick boost of vitamins but are often high in sugar and lack essential nutrients like protein and healthy fats. Their restrictive nature can lead to an unbalanced diet and unwanted side effects.

On the contrary, some cleanses, particularly colonics or those involving laxatives, can disrupt the natural balance of your gut microbiome by flushing out beneficial bacteria along with waste. A diet rich in fiber and whole foods is a more effective way to support gut health.

Common side effects include fatigue, headaches, dizziness, nausea, bloating, and diarrhea due to sudden and severe dietary changes and caloric restriction. Extreme cases can lead to more serious issues.

Many herbal detox supplements are unregulated by the FDA and can contain inaccurate labels or harmful ingredients. It is crucial to consult a healthcare provider before taking any supplements, as some can cause serious health problems.

The safest and most effective alternative is to adopt long-term healthy habits. This includes eating a balanced diet with plenty of fruits and vegetables, staying hydrated, exercising regularly, and getting enough sleep.