Do juice cleanses really detox your body?

Two US juice studies measured weight and microbiome changes, not toxin removal. Why a short-term change does not establish a cleanse benefit.

Prepared by PoshanSense · AI-assisted educational writing
Our sources and editorial approach · Not clinically reviewed

Research explained · Published 2017 & 2025

The promise is attractive: a few bottles, a few days and a fresh start. After a busy week or an indulgent meal, “cleanse” makes restriction sound like maintenance. The important question is what, exactly, is being cleaned out.

A credible detox claim needs a defined substance, a measure of its removal and evidence that the change benefits health. A lighter feeling, a lower scale reading or a different bacterial profile does not fill those gaps.

The often-cited study measured changes, not detox

A 2017 UCLA study followed participants through a three-day juice-only programme and a return to their usual diet. Researchers measured weight, microbiome composition and selected biochemical markers.

Some measurements changed after the juice period. However, there was no concurrent comparison group in the published analysis. Participants changed their whole eating pattern, so the study cannot identify a special cleansing effect of juice rather than restriction, different foods or other aspects of the programme.

A smaller number on the scale is not the same answer

The programme supplied a restricted energy intake, and weight fell over the short intervention. That observation does not establish how much was fat, how much reflected other short-term changes, or whether a juice programme is an effective long-term weight strategy.

The published analysis also excluded five participants who could not provide required stool samples. That makes the analysed sample smaller than the enrolled group. Although the paper uses randomisation language, the reported before-and-after comparison does not provide a control arm capable of supporting a causal detox claim.

The study used departmental UCLA funds and reported no competing interests. A named commercial supplier provided the juices used; that detail identifies the programme rather than making all juices equivalent. Its specific blends even supplied fibre, so assumptions about every strained juice would be inappropriate.

The 2025 experiment does not establish damage either

A later US experiment compared juice-only, juice-plus-food and a plant-based whole-food pattern for three days. Twenty-five people consented, 23 completed activities and only 14 were used for the full analysis, divided into very small groups.

Researchers found changes in oral microbial composition, while overall gut composition did not show a clear shift from the intervention. Some bacterial findings were linked in the discussion to inflammation or disease research. The trial did not demonstrate that participants developed those conditions.

Calling this “juice causes brain damage” would be as unsupported as calling the earlier experiment “juice removes toxins.” The later study measured microbiome responses, not those clinical outcomes. Both require a careful boundary between an interesting marker and a health conclusion.

Juice can remain a drink

Rejecting a detox promise does not require treating every glass of juice as a disaster. A drink with a meal and a juice-only regimen are different choices. The question here is the extra health claim attached to replacing normal eating with a programme.

Whole foods, blended drinks and strained juices also differ in form and composition. Read the ingredients and portion rather than letting the word “fruit” or “cold-pressed” answer every nutritional question. The studies do not establish a need to buy a special bundle after an ordinary meal.

Before starting a restrictive programme

NIH guidance describes the limited evidence for detox diets and advises discussing planned cleanses with a health professional. That is particularly relevant when medicines or a medical condition make a major diet change less straightforward.

The answer need not be dramatic. A short programme can change measured weight or microbes without proving cleansing, durable benefit or inevitable harm. Keep the drink in its ordinary role and ask for evidence before paying for the promised reset.

Published 11 October 2026 · Sources checked 11 October 2026. Suggest a correction.