Magnesium Beta-Hydroxybutyrate (BHB) is the same ketone body bound to magnesium, a mineral involved in turning food into usable cellular energy.
Ketone-salt blends are typically balanced across multiple mineral carriers rather than loaded entirely onto one, which is the reasoning behind including three separate BHB salts.
Its individual amount within Burntide's 525mg blend isn't broken out on the label.