You don't really need lavender it is just for fragrance, you could use olive oil only.
The smell of lavender isn't very strong if you only put one drop.
I only use it because it smells nice and I have it lying around.
On a side note, apparently lavender oil has beneficial qualities especially if rubbed on the soles of your feet where your skin pores are large.
It is claimed to reduce anxiety and help you sleep more easily.
I've been using it lately because I can't sleep for shit. Don't know if it is all placebo but it seems to work.
You get a really nice soothing warm sensation that lasts a long time which feels great when you go to sleep especially if your feet are killing you.