The idea is that seawaters — rich in minerals like magnesium, potassium, calcium, sodium, and iodine — help nurture skin. The salty waters can also help detox. “Whatever your skin and body needs, it will take from seaweed and seawater. Whatever your skin and body have excess of, it will detox it,” Fournier says. “You see the difference in your skin, and it helps you feel lighter."