Safety and Dilution
Essential Oils are safe and powerful Essential Medicine. It is best to start with heavy dilution and know you can always increase the ratio. 1 drop per teaspoon is a vey heavily diluted start point. We want to dilute more heavily for children and Elders. Dilution Ratios depend on:
condition being treated and whether it is acute or chronic
the method of application and the body area
the integrity of the skin
the age of the individual
This is an excellent article on safety and dilution. https://www.doterra.com/US/en/essential-oil-safety
For Aromapoint Therapy, which is a very localised application these are the guidelines:
Tree Oils = 25 -50 %,
Flower Oils = 10-15 %,
Citrus Oils 25 %,
Spice Oils usually @ 25%
Most others are 25 - 50 %
Photosensitization
All Citrus Oils (except for Green Mandarin) are photosensitive, which means if you apply the Oil to the skin, and then expose the skin to the sun it may cause a reaction for up to 12-24 hours following application.
References
The School for Aromatic Studies
Aromapoint Mastery with Tiffany Carole
Aromatica Vol. 1 Peter Holmes