Headaches, feeling cold, hunger during the juice cleanse?

Most symptoms during a juice cleanse occur because your body is adjusting. You're getting less energy, less salt, and no more coffee. You feel this most during the first two days. After that, things settle down considerably for many people.

First, it's important to note that not every symptom during a juice cleanse is harmless. Severe symptoms aren't a sign that the cleanse is working especially well. They're a signal you should listen to. Our article explains whether a juice cleanse is right for you.

Headaches are the most common complaint during a juice cleanse. The most frequent cause often isn't fasting at all, but coffee. If you're used to drinking two or three cups every morning and suddenly stop, you'll also have to deal with caffeine withdrawal.

A randomized study of 100 regular coffee drinkers shows this clearly. On days without caffeine, 30 percent had headaches, compared with just 10 percent on days when they drank coffee (Randa and colleagues, 2026). Giving up coffee therefore doubled the risk, and the pain was more severe. This is exactly what many coffee drinkers experience on the first morning of a juice cleanse. On top of that, many people don't drink enough during a juice cleanse because they count the juices as fluids.

What helps most is planning. Gradually cut back on coffee in the days beforehand instead of stopping overnight. Our article on preparing for a juice cleanse explains how. In addition to the juices, drink water and herbal tea throughout the day. The German Nutrition Society (DGE) recommends at least 2.5 liters a day during therapeutic fasting (DGE, 2018). A walk in the fresh air can often help, too.

Many people notice it in their hands and feet. You feel cold more easily during a juice cleanse, even when the room isn’t cold. A review cites sensitivity to cold and lower blood pressure as common effects of a severely restricted diet (Schweizer Zeitschrift für Ernährungsmedizin, 2022). Your body has less energy available and turns down heat production slightly.

During the first few days, you also excrete more water and salt. This can put a strain on your circulation, especially when you stand up quickly. So get up slowly in the morning and sit on the edge of the bed for a moment. A major health insurer explicitly lists chills, circulatory problems, and fatigue as possible side effects of juice fasting (Angestellten-Krankenkasse, 2025).

For feeling cold, the solution is what might sound old-fashioned. Dress in layers, keep a hot-water bottle handy, and drink warm tea. Light exercise gets your circulation going; a short walk is enough. A warm foot bath in the evening can help you fall asleep. Feeling cold during a juice cleanse is unpleasant, but on its own it’s no cause for concern as long as your circulation remains stable.

Hunger during a juice cleanse rarely means a genuine lack of energy. Much more often, it’s habit. You’d normally have lunch at noon and a snack at four, so your body signals that it’s time to eat. This feeling often comes in waves and then passes.

A juice cleanse provides more energy than traditional therapeutic fasting. According to the nutritional information, the BESSERE SAFTKUR PLUS contains 731 to 885 kilocalories per day. Buchinger fasting provides just 200 to 250 kilocalories. Even then, in a large observational study of 1,422 people who fasted, over 93 percent said hunger wasn’t a problem (Wilhelmi de Toledo et al., 2019). However, participants fasted under medical supervision.

What helps is having a routine. Drink the juices at set times based on your usual mealtimes. When a wave of hunger hits, first have a large glass of water or tea. Also find a distraction, preferably something unrelated to food. A phone call, a short walk outside, or a book can help you get through a wave of hunger during a juice cleanse. Our article on calories and sugar in a juice cleanse explains how much each juice contains.

Most symptoms during a juice cleanse are unpleasant but harmless. In the study mentioned, serious side effects occurred in less than one percent of participants (Wilhelmi de Toledo and colleagues, 2019). Still, there are signs that mean you should stop. So pay close attention to how your body feels during a juice cleanse, especially during the first two days.

• Severe dizziness or feeling like you might faint
• Racing or irregular heartbeat
• Very severe headaches, especially with vision problems
• Trembling, weakness, and confusion
• Symptoms that get worse rather than better after the second day

Then stop the juice cleanse and eat something light, such as soup. If your symptoms are severe or persistent, seek medical advice. The health insurance fund also recommends having an easily digestible meal if you feel unwell (Angestellten-Krankenkasse, 2025). This is not a failure. Our article on stopping a juice cleanse explains how to pause a cleanse safely.

Headaches, chills, and hunger during a juice cleanse are common and usually harmless. They occur mainly at the beginning and have clear causes, especially the lack of coffee, too little fluid, and the new routine.

With preparation, warmth, water, and set times, you can head off most discomfort. For severe or persistent symptoms, follow one simple rule: your body comes before any plan, so stop the juice cleanse.