A lotion by definition is an emulsion of fats and water, and I was replying to that specific situation.
If you change the situation to an anhydrous salve or balm, the common wisdom says no preservative is required because there is essentially no water available in the balm or salve for microbes to use.
If you change the situation to an anhydrous salve or balm, the common wisdom says no preservative is required because there is essentially no water available in the balm or salve for microbes to use.