What should you know about hair test for food intolerance?

These kits may examine a hair sample using methods that are not established for diagnosing food intolerance. A positive result can lead to unnecessary food restriction, while a negative result may give false reassurance. Food intolerance describes difficulty digesting or reacting to a food without the immune emergency pattern seen in some allergies. Symptoms can include bloating, abdominal discomfort, or diarrhoea, but these symptoms have many possible causes.

A clinician will consider the timing of symptoms, foods eaten, medicines, bowel habits, and relevant medical history. An allergy and an intolerance are assessed differently, so avoid treating a hair report as an allergy test.

Keep a short diary of meals, symptoms, timing, and portion size. Do not remove several foods at once or make major dietary changes without advice, because this can reduce nutritional variety and make the trigger harder to identify. A clinician or dietitian may suggest a planned elimination followed by careful reintroduction when appropriate. Read about [Food Intolerance](/conditions/food-intolerance/) and [Food Intolerance Testing](/treatments/diagnostics-and-screening/food-intolerance-testing/) to understand the assessment.

Seek urgent help for swelling of the lips or tongue, trouble breathing, faintness, or rapidly spreading hives after eating. Arrange medical review for persistent vomiting, blood in the stool, dehydration, unexplained weight loss, or symptoms that repeatedly interrupt sleep. For ongoing [Bloating](/symptoms/bloating/) or [Diarrhoea](/symptoms/diarrhoea/), a clinician can check for causes beyond food intolerance.

Ask which diagnoses could explain the pattern, whether a supervised food trial is suitable, and how to protect nutrition while testing a suspected trigger. Bring the hair report if you already purchased one, but also bring your symptom and meal diary.