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SupplementScience

Wheatgrass Side Effects & Safety

Reviewed by·PharmD, BCPS

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Nausea — the most common side effect, especially when taken on an empty stomach or at higher doses
  • Headache — reported in some users, possibly related to detoxification or chlorophyll sensitivity
  • Mild diarrhea or loose stools, particularly during initial use
  • Allergic reactions possible in individuals with wheat or grass allergies (note: wheatgrass harvested before jointing is typically gluten-free, but cross-contamination risk exists)
  • Mold contamination risk — home-grown wheatgrass trays can harbor mold if improperly maintained

Drug & Supplement Interactions

  • Anticoagulants (warfarin) — wheatgrass contains vitamin K which may reduce anticoagulant efficacy
  • Diabetes medications — may have additive blood sugar lowering effects; monitor glucose closely
  • Immunosuppressants — wheatgrass may stimulate immune function; theoretical concern for transplant patients
  • Iron supplements — high iron content may contribute to excess iron intake in non-deficient individuals

Maximum Dose

Do not exceed: 10g powder or 120ml juice daily (higher doses may cause nausea)

Full Wheatgrass Guide

References

  1. Ben-Arye E, Goldin E, Wengrower D, Stamper A, Kohn R, Berry E (2002). Wheat grass juice in the treatment of active distal ulcerative colitis: a randomized double-blind placebo-controlled trial. Scandinavian Journal of Gastroenterology. DOI PubMed
  2. Marwaha RK, Bansal D, Kaur S, Trehan A (2004). Wheat grass juice reduces transfusion requirement in patients with thalassemia intermedia: a pilot study. Indian Pediatrics. PubMed
  3. Bar-Sela G, Tsalic M, Fried G, Goldberg H (2007). Wheat grass juice may improve hematological toxicity related to chemotherapy in breast cancer patients: a pilot study. Nutrition and Cancer. DOI PubMed
  4. Shakya G, Randhi PK, Pajaniradje S, Mohankumar K, Rajagopalan R (2016). Hypoglycaemic role of wheatgrass and its effect on carbohydrate metabolic enzymes in type II diabetic rats. Toxicology and Industrial Health. DOI PubMed
  5. Parit SB, Dawkar VV, Tanpure RS, Pai SR, Ambavade SD (2018). Nutritional quality and antioxidant activity of wheatgrass (Triticum aestivum) unwrap by proteome profiling and DPPH and FRAP assays. Journal of Food Science. DOI
  6. Chauhan M (2014). A pilot study on wheat grass juice for its phytochemical, nutritional and therapeutic potential on chronic diseases. International Journal of Chemical Studies.