CleanAmp™ dNTPs contain thermolabile modification groups that allow for a dNTP-mediated Hot Start activation approach in PCR. The introduction of temperature sensitive protecting groups onto the 3’-hydroxyl of a dNTP blocks primer extension at the less stringent, lower temperatures of PCR reaction preparation. When the reaction is heated to the elevated temperatures of PCR, the protecting group is removed to form the corresponding standard dNTP, which is now a suitable DNA polymerase substrate.