kudos to Merlin for his well researched answer. I'll only reiterate that Ylang Ylang is very much the most notable essential oil for lowering blood pressure. OPTIMALLY, it would be used in a massage oil base, and one would be getting hints of the oil throughout the treatment. But even so, ylang ylang can be used in a carrier such as Jojoba for self massage, or diffused lightly in your environment. The oil's aroma can be a bit 'heady' so it's best to use it at 'just' detectable levels.