Vitamin A? Cod liver oil? No carbs there, what I take. I've tried a bottle of Dave Asprey's c8 "brain octane" oil that was on a good sale, otherwise would buy something cheaper. I didn't experience the mental clarity and energy above my just fine normal which I think is a good indication I'm already in ketosis enough on a daily basis it didn't matter adding the c8 oil. Would probably make a big difference for someone who's usually not, that they would get those noticeable effects. Like Martin said, I'm not deficient in ketones in this case.