Overview

Green juice is extracted from vegetables — commonly celery, kale, spinach, and cucumber, often with apple or lemon for flavor — using a juicer or cold press, which separates liquid from the fibrous pulp. It has become popular as a convenient way to consume a large volume of vegetables at once, and is heavily marketed around “detox” and cleansing claims.

Nutrition and the fiber trade-off

Green juice does deliver concentrated vitamins, minerals (notably vitamin K, vitamin C, potassium, and folate from leafy greens), and plant compounds from several servings of vegetables in one drink. The key nutritional trade-off is fiber: juicing removes most of the insoluble fiber that whole vegetables provide, which affects satiety, blood sugar response, and digestive/gut-microbiome benefits associated with fiber intake. Whole or blended (smoothie) vegetables generally offer these fiber-related benefits that straight juice does not. Green juice can reasonably be one way to add vegetable nutrients to a diet, but it isn’t nutritionally equivalent to eating the same vegetables whole, and shouldn’t be relied on as a primary vegetable source.

The “detox” claim

No major health authority endorses juice cleanses as effective for “detoxification” — the body’s liver and kidneys handle toxin clearance continuously regardless of juice intake, and there is no rigorous clinical evidence that juice cleanses provide measurable detox benefits beyond normal organ function. Green juice can still be a reasonable way to enjoy vegetables and stay hydrated; it’s the specific “cleanse/detox” marketing claim that lacks evidence.

Safety and contraindications

Vitamin K and blood thinners: Kale and spinach are high in vitamin K; people on warfarin or similar anticoagulants should keep intake consistent and coordinate with their prescribing clinician rather than making large, unpredictable changes.
Oxalates and kidney stones: Spinach is relatively high in oxalates; people prone to calcium-oxalate stones should moderate large, frequent green juice intake.
Blood sugar: Juices with more fruit than vegetable content can raise blood sugar quickly due to the lack of fiber; those managing diabetes should favor vegetable-forward, low-fruit recipes and monitor response.
Unpasteurized juice: Fresh-pressed juice from juice bars is often unpasteurized, which carries a small risk of foodborne illness; pregnant individuals, young children, older adults, and immunocompromised people are generally advised to choose pasteurized options.

Sources

Clinically reviewed by Dr. Shilpa Thakur. Last reviewed 2026-07-20. Educational information, not medical advice; consult a qualified clinician about consistent vitamin K intake if taking blood thinners.