Botulism toxin is the cause of Botulism, but the amount of units is very different among different preparatios of the Botulism toxin, as an example 1 U. of Botox is not equivalent to 1U of Dysport, another preparation of Botulism toxin. So when talking about how many units of Botulism toxin are safe, you need to refer to that particular preparation of the toxin and studies for that.
Your question is not based on facts. Cosmetic Botox preparation is not the same as organic Botulinum Toxin and there is no "Research" that suggests that "People have been hospitalized and/or died w/less than 10 U". Please refer to the copious legitimate research on line. I would recommend only seeking treatment with Cosmetic Botox by a qualified and experienced DOCTOR for best safety and cosmetic results.