A subterranean product extraction composition may include a borehole fluid that may include a thiamine based shale inhibitor active to inhibit reactivity of a formation shale to a base fluid of a borehole fluid. A method of extracting a subterranean product via a borehole may include providing a borehole fluid containing a thiamine-based shale inhibitor and inhibiting reactivity of a formation shale contacted with the borehole fluid. A system for extracting a subterranean product via a borehole may include a tubular having an end in proximity to a formation shale and in fluid communication with a container dispensing a borehole fluid containing a thiamine-based shale inhibitor. The thiamine-based shale inhibitor is inert to the borehole fluid and has superior activity as compared to potassium chloride to inhibit shale reactivity. The borehole fluid may be a drilling fluid. The base fluid may be water.