Brewers dried yeast is a byproduct of the beer brewing process that has been dried and packaged into a nutritional supplement for pets and livestock. It is a rich source of protein, amino acids, B-vitamins, and minerals such as zinc and selenium. Brewers dried yeast is commonly added to pet foods to support healthy skin and coat, boost the immune system, aid in digestion, and provide energy. It may also help repel fleas and ticks due to its high levels of thiamine. Brewers dried yeast can come in powder or pellet form and can be given as a standalone supplement or mixed with food.