What is the ruling on consuming bovine serum found in dietary supplements ("protein") and on the fasting of its consumer?

First: "Bovine blood serum" is not used in nutritional supplements; rather, "whey protein" is used, which is permissible (halal (definition)).

Second: If serum were to be extracted from blood, scholars have differed regarding its permissibility based on the concept of "transformation" (istihalah). Those who consider transformation to be a purifying agent permitted its consumption, while those who do not consider it purifying did not permit it. It has been stated in the recommendations of the Symposium on the Islamic Vision of Medical Issues that additive substances of impure or prohibited origin become legally permissible through transformation (istihalah), which is defined as: "The change in the reality of an impure or forbidden substance, and the reversal of its essence into a substance distinct from it in name, characteristics, and properties." Based on this, chemical compounds extracted from impure or prohibited origins that undergo transformation are considered pure and permissible for consumption. However, those that have not undergone transformation are not permissible for use. The consumption of this serum is considered permissible as long as it has undergone transformation and its properties have changed from the original nature of blood.