IJRAP International Journal of Research in Ayurveda and Pharmacy 2277-4343 Moksha Publishing House 10.7897/2277-4343.173107 A NARRATIVE REVIEW WITH IMPLICATIONS FOR THERMAL PENETRATION DEPTH IN NABHI CHIKITSA (NAVEL OIL THERAPY) Chirag Warty Manaswi Rajurkar * 11 -0001 119 124 Background: Nabhi Chikitsa (navel oil therapy) is an Ayurvedic practice involving the application of warm, medicated oil to the umbilicus for therapeutic effect. Its efficacy depends on thermal and molecular penetration through the peri-umbilical subcutaneous adipose tissue (SAT) layer to reach underlying target structures. The depth of this SAT layer is the principal anatomical determinant of thermal penetration depth, transdermal drug-delivery efficiency, and the time required for dermally absorbed molecules to reach sub-fascial structures. Despite its clinical relevance, no review of peri-umbilical SAT thickness variation by body mass index (BMI), sex, and age has been published in the context of Nabhi Chikitsa. Scope: This narrative review synthesises published literature on peri-umbilical SAT thickness by ultrasound, MRI, CT, and caliper in healthy adults, examines the influence of BMI, sex, age, and ethnicity, and discusses pharmacokinetic and thermal implications for Nabhi Chikitsa protocol individualisation. Key Observations: Peri-umbilical SAT thickness varies widely, is primarily determined by BMI, and is significantly modified by sex, age, and ethnicity. South Asian individuals show relatively lower peri-umbilical SAT at equivalent BMI than European-ancestry populations. Published bioheat principles and established transdermal pharmacokinetic frameworks predict that obese patients receiving standard protocols will achieve substantially lower sub-fascial thermal and molecular delivery than lean patients. Conclusion: A BMI-stratified protocol framework for Nabhi Chikitsa is proposed, adjusting oil temperature, session duration, oil volume, and herbal concentration according to estimated peri-umbilical SAT thickness. Prospective experimental validation of these recommendations is required. Subcutaneous adipose tissue Nabhi Chikitsa (navel oil therapy) BMI thermal penetration transdermal drug delivery