It is not recommended to use the serum in conjunction with Frizz Ease 3-Day Straight^™ Flat Iron Spray. Doing so can cause a negative impact on the straightening durability over time (days 2 and 3) and has the potential to make hair feel weighed down on days 2 and 3. For spot frizz-fighting treatment of dry damaged hair, the Thermal Serum may be applied to the ends.