If using a plain oil for its DHT blocker properties, you should indeed only keep it as pre-poo mask on your scalp as adding oil on a daily basis on your scalp may result in harmful build up. This will not allow you to add considerable amount of the ingredient so the effects may not be huge but it's always a good addition to your routine that will compound with the other better practices that you'll pick up in the Lab. If you want to be more intense with your DHT blocker action: some clinical trials suggest that rosemary essential oil (diluted) applied 2x a day on the scalp provided similar to better results than minoxidil through a period of 3 month of application. This is very frequent application so it can become quite draining to follow. If you want to try this technique, we recommend you dilute 3-5 drops of your essential oil in a small spray bottle with water in order to avoid over-oiling your scalp with this practice. Make sure to monitor VERY closely your scalp through these tests as such frequent application of essential oil may result in skin irritation or other reactions. Stop this practice if you start feeling any bad symptom.