According to the manufacturer's recommendations, Biovital should be used within 1 month of opening, even if you store it in the refrigerator.
After this time, there may be a change in the composition, action of the preparation or the risk of microbial growth, so for safety reasons, I encourage you to stop using it and buy a new bottle. Refrigeration slows down the growth of microorganisms, but does not guarantee full stability of the product after the recommended time.
The availability of Biovital in pharmacies in Polish can be checked at the following address:
https://www.gdziepolek.pl/produkty/99557/biovital-zdrowie-plus-plyn/apteki
https://www.gdziepolek.pl/produkty/12079/biovital-pamiec-plyn/apteki