The products' efficacy, however, is debatable: Can you really absorb caffeine through the skin? Unlikely, says WiseGeek. Shower water quickly dilutes the soap... plus you're rinsing the stuff off ...

can be achieved with caffeine hair products. And don't just take our word for it, there are studies showing that caffeine is ...

Hairstylists and trichologists weigh in on the trendy ingredient. Just like a cup of coffee can turn a groggy morning into a ...

But labels don't have to reveal how much caffeine the products pack. We will. We measured the amount in 27 top-selling energy drinks and shots (see table below). We bought the drinks online or at ...

The American Academy of Pediatrics recommends against giving caffeinated products to children under 12, while adolescents between ages 12 and 18 shouldn't exceed 100 milligrams per day.