'Wellness' vapes containing vitamins and caffeine raise potential safety concerns

Feeling tired? Need a quick boost? Fancy inhaling your caffeine instead of drinking it? What about breathing in some Vitamin B12? Websites abound that boast "revolutionary" vapes that let you inhale "pure focus". And if you need to get to sleep instead, they give you the option of being wrapped in a "mist of relaxation" with one of their melatonin vapes. Still others offer "vitamin-infused" aromatherapy in, of course, a variety of sweet and fruity flavours. But seductive flavours and scents aside, does inhaling vitamins and caffeine instead of ingesting them actually work? And how safe is it?