Shelf life for both SSKI and Lugol's is at least 5 years, stored airtight and away from light. By the way, my own experience with the Tri-Quench was that the bottle contained about 1000 real-world drops, not the 1200 theoretical listed on the label. L-selenomethionine is the preferred form of selenium, 200 mcg - 400 mcg. For 2 drops of SSKI I'd take the lower amount.