A total of 105 studies were reviewed, including 15 randomised controlled trials (RCTs) in chronic pain, autoimmune and neuroimmune disorders, gastrointestinal disease, dermatological conditions, post-infectious syndromes, mental health and oncology.
Across these fields, early positive findings from uncontrolled studies were rarely replicated in placebo-controlled trials. Most available evidence consists of case reports and small feasibility studies that are prone to publication bias and rely heavily on subjective outcomes.
LDN is generally safe, inexpensive and well tolerated, with most studies using a daily dose of 4.5 mg.
Although these features contribute to its appeal, current evidence does not support routine clinical use.