The full answer
Typically months to a couple of years
Small intestine healing after starting a gluten-free diet is a gradual process. Children often heal faster (sometimes within a year), while adults — especially those diagnosed later in life or with more extensive damage — can take one to two years or longer for the intestinal lining to fully recover.
Why strict adherence matters here specifically
Ongoing accidental gluten exposure, even in small amounts, can repeatedly restart the damage and delay healing — this is a major reason strict cross-contact avoidance matters even after symptoms have improved.
Important context
Individual symptoms, reactions, medical histories, food products, and local labeling rules can vary. Community experiences are not medical evidence.
For personal medical decisions, diagnosis, testing, or treatment, consult a qualified healthcare professional.