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Why do you get headaches from a juice cleanse?


Juice cleanses have become increasingly popular in recent years as a way to detox and reset your body. Many people choose to do a juice cleanse when they want to lose weight quickly or improve their overall health. While juice cleanses may seem like a great idea in theory, they can often lead to side effects like headaches. In this article, we’ll explore some of the reasons why you may get headaches when doing a juice cleanse.

What is a juice cleanse?

A juice cleanse typically involves consuming only fresh fruit and vegetable juices for a period of 3-5 days while eliminating all solid foods. Some popular juices used in cleanses include combinations of fruits and veggies like kale, spinach, celery, cucumber, apple, carrot, beet, ginger, and lemon.

The goal of a juice cleanse is to flood your body with nutrients while giving your digestive system a rest from processing solid foods. This is said to allow your body’s natural detoxification systems to clear out toxins that have built up from poor diet, alcohol, medications, environmental pollutants, and stress.

Why juice cleanses can lead to headaches

There are a few key reasons why juice cleanses often result in headaches for many people:

Low calorie intake

One of the biggest factors is that juice cleanses provide very few calories, often only around 700-1,000 calories per day. For most adults, this severe calorie restriction results in headaches, fatigue, irritability, and mental fogginess.

Our brains require a steady supply of glucose from carbohydrates to function properly. When carb intake drops very low, the body responds hormonally to boost blood glucose. This rapid fluctuation in blood sugar and stress hormone levels is a common trigger for headaches.

Caffeine withdrawal

Since caffeine is not allowed on most juice cleanses, those used to having several coffees or teas daily will likely experience caffeine withdrawal headaches. Caffeine narrows blood vessels in the brain, so when you remove it abruptly, they dilate and swell, causing pain.

Lack of protein

Protein is needed to produce neurotransmitters like serotonin that regulate pain perception in the brain. Juice cleanses may provide inadequate protein for your individual needs, contributing to headaches.


Even though juice cleanses provide fluids, they often contain diuretic ingredients like caffeine, apple cider vinegar, and lemon juice that increase urination. Insufficient water intake combined with low sodium from juice-only diets can lead to dehydration headaches.

Changes in gut flora

Eliminating all fiber and solid foods for several days alters the microorganisms in your gastrointestinal tract. This sudden change to your gut flora combined with increased sugar from fruit juices may result in inflammation that triggers headaches.


Feeling ravenous can itself cause headaches or migraines in some individuals as a result of very low blood sugar. Juice cleanses often leave people feeling unsatisfied and absolutely starving, an obvious recipe for head pain.

Stress and anxiety

For some people, the idea of strictly sticking to a restrictive juice cleanse causes mental stress. Anxiety about following the rules, planning juices, avoiding real food temptations, and general nutrition deprivation can manifest as tension headaches.

Nutritional deficiencies

In addition to the reasons above, certain nutritional deficiencies resulting from prolonged juice cleanses may contribute to headaches:

Nutrient Role Deficiency effect
Sodium Fluid balance, nerve signaling Low sodium can cause headaches, nausea, fatigue
Magnesium Muscle and nerve function Low magnesium is linked with migraines
B-vitamins Energy production, brain chemicals Deficiencies associated with headache disorders

Without adequate intake of these nutrients from real whole foods, headaches may develop as your body struggles to function normally.

Other side effects

In addition to headaches, some other common side effects people report from juice cleanses include:

– Fatigue and weakness
– Nausea
– Irritability and mood swings
– Brain fog and difficulty concentrating
– Hunger and food cravings
– Insomnia
– Constipation
– Muscle cramps

These effects result from the extreme and rapid diet change, calorie restriction, caffeine withdrawal, and nutritional deficiencies. Your body is essentially being put into a state of starvation and distress.


In summary, there are many mechanisms, both direct and indirect, that explain why headaches are a common complaint during juice cleanses. The radical shift away from normal food intake to very low calories devoid of protein, fat, fiber and chewing causes physiological stress. Caffeine withdrawal, dehydration, inflammation, and nutritional imbalances also play a role for many people.

While proponents claim juice cleanses detoxify and provide nutrition, the drawbacks tend to far outweigh any benefits. For sustaining healthy habits long-term, make more gradual, reasonable changes to your diet instead of shock treatment from radical cleanses. Be sure to include balanced nutrition with wholesome complex carbs, protein, healthy fats, and plenty of water every day to prevent headaches and feel your best.