What is the ruling on using substances to which animal glycerin or animal mono- and diglycerides have been added? Is it obligatory to inquire and investigate their source, or is that considered an excessive burden? And what is the response to those who say that the basic principle is permissibility and facilitation?

The materials used in products such as creams, soaps, and toothpastes are either derived from animal fats and greases, or from plant-based or synthetic materials.

1. Animal Materials: Permissible: If they are from animals that are permissible and slaughtered according to Islamic law, or marine animals that do not require ritual slaughter, then their use is permissible. Forbidden: If they are from forbidden animals (like pigs) or permissible animals that were not slaughtered according to Islamic law (carrion), then their use is forbidden. The Permanent Committee emphasizes the prohibition of eating, drinking, or anointing with anything confirmed to contain pork, and anything doubtful should be avoided.

2. Istihalah (Transformation of Substance): If fats and greases are completely transformed into another substance, losing their original properties and name, they then take the ruling of the new substance. The Islamic Organization for Medical Sciences holds that istihalah transforms impure or forbidden substances into pure and Islamically permissible ones, such as soap produced from pig fat after its essence has undergone istihalah.

3. Animal Materials of Doubtful Slaughter: The default is not to use them if it is not known whether the permissible animals were slaughtered according to Islamic law or not; because the default ruling for slaughtered animals is prohibition unless their permissibility is clear, by analogy with what is mentioned in the hadiths about hunting.

4. Synthetic and Plant-Based Materials: Their use is permissible unless they are inherently harmful or poisonous, or when combined with other materials.

5. Investigation and the Principle of Things: A Muslim must investigate what they eat, drink, and all their affairs. The default ruling for manufactured materials like creams and soaps is permissibility, unless it is proven with certainty or highly probable that they are contaminated with impure or forbidden substances, in which case their use becomes forbidden. Mere rumors do not necessitate avoiding them.