If you can't find it on the shelf, these Russian marketplaces offer same-day or next-day delivery in Moscow: Ozon / Wildberries
A dedicated cheesemaking supply store that ships throughout Moscow. Yandeks Market E-commerce service
Search for "сычужный фермент" or "пепсин". They offer numerous liquid and powder options. Syrnyy Somel'ye Cheese shop OpenBol'shoy Drovyanoy Pereulok, 6
