Endothermic atmosphere is prepared by reacting a mixture of hydrocarbon gas, typically methane or. propane and air, metered in a proportion such that there is just enough oxygen to form carbon monoxide. and hydrogen without excess carbon dioxide or water vapor.
But for your everyday run-of-the-mill deep conditioner, it should begin to work instantly, and reach maximum capacity at around the 20 or 30 minute mark. If your deep conditioner doesn't work after 30 minutes, it's time to ditch it for one that's more effective.
Leave the toner in your hair for about 30 minutes. This varies depending on the product you are using, but 30 minutes is about the norm. Wait until the toner turns a dark purple in your hair. Check your hair after about 15 minutes to see how it looks by wiping off some of the purple toner.