My logic is that you get familiar to a scent. And so when you sniff it in the surrounding, it induce you to sleep. I even have scents to keep me alert as well. Haha. I have tried many different brands of essential oils and I realize that there is a reason why some are more expensive than the other.
I ever tried the S$2 type from Diaso, but it just cheap and a little bit pungent. Never went back after. I also tried the Body Shop. It was really nice but they have limited selection, so I am quite pleased to share with you Rosmosa.
For sleep, I think I am quite an expert in it. I usually suggest Lavender. You can dilute it in a spray or pour 2-4 drops in your humidifier. It acts as a good room freshener as well. I only started using Lemongrass recently cos of its insect repellant nature. Surprising it went pretty well with Lavender.
Rosmosa also sells other form of essential oils. But I am only familiar with 2 others (cos I am using them) - Tea Tree for treating pimples and Argan Oil for smoother hair. I do hear some essential oils can be consumed but I have done that and I don't think Rosmosa's are meant for consumption.
I do occassionally use it for massage. (More like forcing the BF to massage me LOL!) Doubt they have any healing power per say, but it helps me to relax while the masseur (BF will be sad to know of his new profession hahaha)release the tension. By the way, Rosmosa also have a pretty good selection of humidifiers and at very reasonable price. Do check them out if you need one. :) (I prefer electronic ones by the way if you are interested.)