Is it safe to put the pure essential oils directly in the bath water?
By Marco Valussi
No. Essential oils are lipophilic substances, which means they dissolve well, enter into solution, in fatty solvents, such as oils or butters, or in apolar or slightly polar solvents, such as ethanol. Which means that if we put a drop of essential oil in the bathtub water, this drop will not dissolve in water but will remain on the surface like a small floating oil stain. Then when you put the essential oil into the tub, it is very likely that your skin will come into contact with undiluted essential oil, with possible adverse effects such as burning, inflammation, and increasing the risk of allergic sensitization. Let's recall the general rule that says no essential oil should be used pure on the skin or mucous membranes, but always diluted to the appropriate extent.
This is because the dilution reduces the likelihood of allergic phenomena, reduces the risk of irritating phenomena, and because it has been proven that it is never necessary to use pure oil to observe the desired effects. For more on proper dilution, read here
To use essential oils safely in bathtub water, or in peduncles, it is necessary to dilute the essential oils in an appropriate carrier, which allows solubilizing or emulsifying the essential oils and which then may be dispersed in Effective way in the water. There are many options, but the simplest and most direct is to mix the essential oil into a sufficient quantity of liquid detergent, which will then be dispersed in the water.