What Happens When You Do a Body Cleanse?

January 9, 2026 •

4 min read

According to the National Center for Complementary and Integrative Health (NCCIH), there is little scientific evidence to support the effectiveness of detox diets and cleanses for removing toxins. So what happens when you do a body cleanse, and what are the actual effects? While many report increased energy and short-term weight loss, the experience can also come with a range of challenging and sometimes risky side effects.

Quick Summary

This article explores the real-world effects of a body cleanse, detailing both the commonly reported benefits and the potential negative side effects. It clarifies the body's natural detoxification processes and provides a reality check on the scientific claims surrounding commercial detox products. Readers will gain a clear, evidence-based understanding of what to expect from a cleansing program and learn about safer, more sustainable approaches to wellness.

Key Points

Natural Detoxification: The liver and kidneys are your body’s powerful, built-in detox system, making commercial cleanses unnecessary.
Temporary Effects: Initial weight loss on a cleanse is mostly water weight and is not a sustainable or healthy weight loss method.
Potential Risks: Side effects can include fatigue, nutrient deficiencies, dehydration, and dangerous electrolyte imbalances.
Unregulated Products: Many commercial detox products lack scientific evidence and are not regulated by the FDA, posing potential health risks.
Healthier Alternatives: Support your body's natural processes with a balanced diet, adequate hydration, regular exercise, and sufficient sleep.
Consult a Professional: Always talk to a doctor before starting a cleanse, especially if you have underlying health conditions.

The Science of Your Body's Natural Detox System

Before delving into what happens during a cleanse, it is crucial to understand that your body already has a highly efficient, built-in detoxification system. The human body is not a machine that accumulates “sludge” or toxins that need periodic flushing out by a special diet.

The Body’s Primary Detoxification Organs

Liver: The liver is the body's primary filter. It processes toxins from everything you eat, breathe, and absorb through your skin, converting them into harmless substances that can be eliminated.
Kidneys: These organs filter waste products and excess fluid from the blood, which are then excreted as urine.
Lungs: The respiratory system filters out airborne toxins and waste products like carbon dioxide.
Skin: Your largest organ acts as a barrier to environmental pollutants and eliminates some waste through sweat.
Intestines: The digestive tract, specifically the large intestine, helps eliminate solid waste.

When a commercial body cleanse is introduced, it is important to remember these natural processes are already at work. The effects people experience are often not due to the removal of mysterious toxins but rather the sudden and dramatic changes to their diet.

Short-Term Benefits and Effects of a Body Cleanse

Many who undergo a cleanse report feeling better, but the reasons are often different from what's advertised. These positive effects are typically short-lived and are often a result of simple dietary improvements or the placebo effect.

Increased Energy: Eliminating processed foods, sugar, and alcohol can lead to an initial boost in energy levels and a feeling of lightness.
Weight Loss: Most rapid weight loss experienced on a cleanse is due to a reduction in water weight and glycogen stores, not actual body fat. This weight is often quickly regained after the cleanse ends.
Improved Eating Habits: A cleanse can serve as a reset button, motivating individuals to continue healthier eating habits after the program concludes.
Increased Nutrient Intake: Liquid-based cleanses consisting of fruit and vegetable juices can provide a temporary boost of vitamins and minerals, especially for those who typically have a nutrient-poor diet.

The Risks and Negative Side Effects

Despite the glowing testimonials, body cleanses come with significant risks and potential negative effects, especially when they involve severe calorie restriction or the use of unregulated products.

Nutrient Deficiencies: Severely restricting food intake or eliminating entire food groups can lead to deficiencies in essential nutrients like protein, iron, and fiber.
Gastrointestinal Distress: Many cleanses include laxatives or diuretics that can cause cramping, bloating, nausea, and diarrhea, which can also lead to dehydration.
Fatigue and Lethargy: Drastically cutting calories can leave the body with insufficient energy, resulting in low blood sugar, fatigue, and difficulty performing daily activities.
Irritability and Mood Swings: Restricting food and coping with side effects like headaches and fatigue can make a person irritable, moody, and anxious.
Harmful Products: Some detox products are unregulated by the FDA and may contain illegal or harmful ingredients, potentially leading to serious health issues like kidney failure.
Metabolic Slowdown: Chronic calorie restriction can slow down the metabolism. Once the cleanse is over and normal eating resumes, the body may convert excess calories to fat more readily, leading to weight regain.

Commercial vs. Natural Body Cleansing


Feature	Commercial Body Cleanse	Natural Body Cleansing
Method	Restrictive diets (juice-only, liquid-only), supplements, laxatives, colonics	Balanced, whole-food diet; hydration; exercise; adequate sleep
Scientific Basis	Limited to no scientific evidence to support toxin removal	Supported by robust evidence for maintaining natural bodily function
Regulation	Often unregulated, with potential for harmful or unlisted ingredients	Safe, sustainable lifestyle changes that support overall health
Effectiveness	Short-term effects, often including rapid but temporary weight loss	Promotes long-term, sustainable health improvements
Risks	Dehydration, nutrient deficiencies, fatigue, digestive issues, potential for unsafe products	Minimal to no risks, focusing on supportive, healthy habits

Sustainable Alternatives to a Body Cleanse

Instead of resorting to potentially dangerous commercial cleanses, supporting your body's natural detox systems is a safer and more effective approach for long-term health. Consider these sustainable habits:

Prioritize Hydration: Drinking plenty of water is essential for your kidneys to flush out waste products effectively.
Eat Whole Foods: A diet rich in fruits, vegetables, and fiber supports your gut health and provides antioxidants that protect your cells.
Get Enough Sleep: Adequate sleep allows your brain to clear waste and your body to repair itself.
Exercise Regularly: Physical activity boosts circulation and helps transport nutrients and waste throughout the body.
Manage Stress: Chronic stress can negatively impact your body's ability to detoxify. Practicing stress-reducing techniques can help.
Limit Processed Foods and Alcohol: Reducing the intake of these items significantly lessens the burden on your body's detox organs.

Conclusion

When you do a body cleanse, the immediate effects can be a temporary feeling of increased energy and initial weight loss, largely due to a sharp reduction in calories and processed foods. However, this often comes at the cost of potential side effects like fatigue, irritability, and nutrient deficiencies. The scientific consensus is clear: the human body is perfectly equipped to detoxify itself through its powerful internal organs, and commercial cleanses are unnecessary, unregulated, and often ineffective. For genuine, long-lasting health improvements, a sustainable approach of a balanced diet, proper hydration, regular exercise, and adequate sleep is the most effective and safest path. Consult a healthcare provider before beginning any restrictive diet or cleanse, especially if you have pre-existing health conditions.

For more information on the safety of detox methods, the National Institutes of Health offers comprehensive resources.

Frequently Asked Questions

No, a body cleanse is not the best way to get rid of toxins. Your body has a highly effective natural detoxification system involving the liver, kidneys, and other organs that work constantly to eliminate waste.

You might feel more energetic because you've stopped consuming processed foods, sugar, and alcohol. This is a common side effect of cleaning up your diet, not necessarily a sign of 'detoxing' harmful substances.

Juice cleanses are generally not a safe or effective long-term weight loss solution. Any initial weight loss is often water and muscle mass, which is quickly regained. These restrictive diets can also cause nutrient deficiencies.

Yes, some extreme cleanses, particularly those involving excessive supplements or high-oxalate ingredients like spinach and beets, can be dangerous for individuals with pre-existing kidney conditions and may cause damage.

Common side effects include headaches, fatigue, irritability, digestive issues (like diarrhea or constipation), dehydration, and mood swings. These symptoms are often related to calorie restriction and dietary changes.

Colon cleanses are generally unnecessary and can be harmful. Your colon is self-cleaning, and using laxatives or irrigation can disrupt its natural function, leading to dehydration, cramping, and electrolyte imbalances.

The safest and most effective way to support your body's natural detox is by drinking plenty of water, eating a balanced diet rich in whole foods, getting adequate sleep, exercising regularly, and managing stress.