When my daughter had a torn rotor cuff, and her shoulder was in a great deal of pain, she applied the entire set of Raindrop oils (Thyme, Basil, Peppermint, Oregano, Wintergreen, Cypress and Marjoram plus Blends: Valor® & Aroma Seiz™), layering them one by one over the area, every single day for a month, and it healed without the suggested surgery.
I realize that this may not be the same problem that you have, but it’s the same thing I would do. I would also add in other oils such as frankincense, copaiba, ocotea, helichrysum, chamomile, and PanAway. (Use whatever you have.) I might also take caps of copaiba every day for awhile, as it’s got the highest quantity of a molecule called beta caryophyllene which is an excellent anti-inflammatory molecule.
The firs that you asked about are all similar, but they also have differences in their chemistry. So yes, the firs can be interchangeable, and your body can select the molecules it needs for repair and regeneration.
I recall one of the French doctors saying that the conifer oils (which would include the firs) were his first choice in cancer prevention. Isn’t that interesting?
Since we cannot tell exactly what the body is looking for in order to heal, it’s always a wonderful idea to offer the body a diverse set of oils, such as Raindrop, in order to have the highest chance that what is needed for healing is in the oils being applied. What works for one person, may not work for another, because their bodies are looking for different molecules.
Isn’t it wonderful that we don’t really need to know a lot about the oils in order to help ourselves and our families live longer, healthier, and happier lives? We can always go to the Essential Oil Desk Reference to see what’s been observed throughout history, and in more recent research, and then we can just have fun applying the oils that we have, and those that appeal to us! Each of the oils has a gift to give us! What a glorious thing!