20 minutes is calculated based on fluency or stream of lasers delivered to the scalp. We based our calculations on years of research in order to reach nearly 7 joules/cm2. Our lasers are designed to produce this much fluency for a continuous 20 minutes. Any less would be inefficient and any more would result in over stimulation which can impede hair growth. Because of Theradome’s heat management system, we can deliver laser therapy without lasers pulsing and interrupting treatment.