Do juice cleanses work? Facts & Criticism

The honest answer is: it depends on what you are hoping to get out of it. As a quiet break from everyday life and a catalyst for new habits, a juice cleanse can have real value. As a miracle cure meant to clean the body from within or ward off illness, it is not.

This isn’t just marketing speak; it aligns with scientific research. Imagine two people doing the same cleanse: one plans it as a period of rest and eats fresher foods afterward; the other wants to lose five kilos quickly and returns to their old eating habits immediately. Same cleanse, two completely different outcomes. The difference rarely lies in the product and almost always in the mindset with which you start. We will go through this mindset step-by-step so that you can make an informed decision for yourself. You can find more on the philosophy behind fasting in our article on the reasons for a juice cleanse.

The realistic benefits

A juice cleanse interrupts your daily routine and makes your eating habits visible. You consume a large amount of fluids and vegetables while avoiding sugar, alcohol, and highly processed foods. You quickly realize how much routines dictate your eating. You drink more throughout the day and learn to recognize your hunger signals better. Many use this time as a starting point to cook fresher and simpler meals afterward. This impulse is the real value, and it is greater than many think.

What you should not expect

You should let go of the idea that juices "cleanse" the body. According to the German Nutrition Society, the concept of "sludge" (Schlacken)—alleged deposits of metabolic waste—does not exist in a healthy body. The liver, kidneys, intestines, and skin are constantly breaking down and excreting unwanted substances themselves. Claims that a cleanse does this are promising something your body is already doing constantly, without any need for juice.

Furthermore, the often-advertised cellular "cleanup," known as autophagy, is not an automatic process. Its research was honored with the 2016 Nobel Prize in Medicine, but it has primarily been proven in cellular and animal models. In humans, the triggers are not yet fully understood. Crucially for practical use: a juice cleanse provides carbohydrates. As a result, insulin levels remain higher than during strict water fasting, and deep fasting states like pronounced ketosis are generally not achieved. Do not confuse a juice cleanse with multi-day water-only fasting, which is a different metabolic state.

The most common valid objection concerns sugar. Many juice cleanses on the market consist primarily of fruit, and fruit juice contains plenty of fructose. A glass of orange juice can deliver as much fructose as a soft drink, even if it feels much healthier. The World Health Organization (WHO) explicitly classifies sugar from fruit juice as free sugars that should be limited; it is recommended that they make up less than ten percent of daily energy intake.

Pure fruit juices provide surprisingly high amounts of sugar and cause blood sugar levels to fluctuate significantly. Furthermore, a small 2025 study found that three days of pure juice fasting can unfavorably shift oral flora toward bacteria associated with inflammation. The researchers attributed this to the lack of fiber but emphasized the small participant group themselves. The solution is simple: the proportion of vegetables must be high and that of sweet fruit low. That is how you recognize a well-thought-out juice cleanse. If you want to dive deeper, you can find more answers in our juice cleanse FAQ.

When it comes to losing weight, honesty is required. The rapid weight loss of the first few days is primarily water. Your body first depletes its glycogen stores in the muscles and liver. Because every gram of glycogen binds water, you lose one to two kilograms initially without burning any fat. Additionally, with low food intake, insulin levels drop, causing the kidneys to excrete more water and sodium. This explains the number on the scale, not a faster metabolism. If you return to old habits afterward, the weight comes back; this is the yo-yo effect. Thus, a juice cleanse is not a substitute for a permanent change in diet; it is at most the starting shot.

Regarding the liver, it is worth looking closely, as there is a kernel of truth here. Fructose is processed almost entirely in the liver, where it promotes the formation of new fat (de novo lipogenesis) when consumed in large amounts. Furthermore, high consumption of sugary drinks has been linked to fatty liver disease. A 2025 analysis of over 120,000 people supports this: those who drink many sugary beverages daily have a significantly higher risk of fatty liver. The decisive factors are quantity and duration. Based on current knowledge, a vegetable-rich cleanse lasting a few days does not burden a healthy liver, but long-term fruit-heavy cleanses are the actual concern. And as for "detox" scams—expensive programs that promise an alleged cleansing of the body—that is exactly what consumer protection agencies warn against.

Whether a juice cleanse is sensible depends heavily on the quality. A high-quality cleanse focuses on a high vegetable content rather than sugar bombs made from fruit. Heat and oxygen are the greatest enemies of the nutrients. During pasteurization, heat destroys part of the vitamin C, folic acid, and secondary plant compounds; during rapid centrifugation, much of this oxidizes in the air. Cold pressing works slowly and with little oxygen, and the HPP process subsequently preserves the juice using high water pressure without heating it. This way, more heat-sensitive nutrients are retained than with conventional processing. Being organic also reduces exposure to pesticides.

At DALUMA, a juice cleanse is more than just juice. It includes active kombucha as a source of pro- and prebiotics, which aligns with our focus on the gut-skin axis, as well as an activated charcoal face mask and a follow-up program for the time after. This turns pure abstinence into a well-rounded concept. Anyone wanting to see the complete setup can find it in the juice cleanse overview.

Does a juice cleanse do anything? Yes, if you view it as a calm break and an impetus for better habits, and if the quality is right. No, if you are hoping for an internal cleansing or permanent weight loss; no cleanse can guarantee that.

You get the most out of it if you choose a vegetable-forward, cold-pressed cleanse, don't expect miracles, and use the time afterward to stay on track. Treat the cleanse as a starting point, not a goal. If you notice that steady rituals make you feel good, you have gained far more than a few quiet days without solid food. This honest perspective removes the false magic from the juice cleanse and gives it a realistic place in a healthy daily routine.