No. There is substantial scientific evidence to suggest that a ketogenic diet and/or consuming exogenous ketones could actually be a very good treatment for diabetes. Many individuals are even able to go off insulin once they switch to a ketogenic diet because it takes away the real culprit (carbs). Ketones don’t require insulin to enter the cells and be used as energy. Therefore, switching the body away from glucose metabolism and towards ketone metabolism is very helpful. Glucose doesn’t store up in the blood (because you’re not consuming carbs), and the impaired insulin signaling isn’t as important since ketones can get into the cells without it.
Plus, as described before, ketones enhance insulin sensitivity. Especially in someone trying to manage their diabetes with a low carb or keto diet, thus, utilizing exogenous ketones to imporve therapeutic ketone levels to the blood also provides this benefit.
The only condition wherein one would expect a diabetic could potentially be harmed by taking this product as it is supposed to be taken, is if that person had extremely uncontrolled diabetes and were already in an acute diabetic ketoacidosis crisis. In that situation, no, they would not want to take exogenous ketones, as it would elevate ketones further. It is almost a impossibility of this situation occurring.
Someone would have to disregard their healthcare to the point of potentially entering diabetic ketoacidosis as or before purchasing or using ketone supplementation.
Please note, Exogenous ketone supplements are not recommended for Type 1 diabetics.