The world of essential oils can be a confusing journey to take. There is so much marketing using 'smoke & mirrors' to sell product. It seems everything contains essential oils today!
I will put together some information on why most essential oils are not meant for internal use and post it in the next couple of days.
I can give you a 'short' answer... they are of a perfume or aroma grade and have been adulterated, cut or processed with toxic substances, not meant to be ingested. Sadly, many of these 'essential oils' are used in personal care products and are absorbed into the body when applied to the skin or used in oral care products.
MY THOUGHTS: The most important lesson I have learned about essential oil use is that what is put on our skin or in our mouth (toothpaste, mouthwash, etc.---even if it is not swallowed) IS absorbed into our body and bloodstream. Just as we should not use personal care products that contain toxic chemicals or un-natural ingredients, we should know that the processes used to produce these lower perfume/aroma grade essential oils can also be toxic/damaging to our body..
I don't use commercial personal care products. There is way too much marketing 'smoke & mirrors' used in the industry to KNOW what is really in the product. I prefer to purchase the things I WANT in my body lotion, soap, etc. and mix it up fresh myself. That way I KNOW what is in it.
Just to clarify---ALL of Young Living's essential oils ARE therapeutic-grade. MOST of them are labeled as SUPPLEMENTS and for dietary use. The few that are not have varied reasons but I will go into these when I do that post for you... hopefully shedding some light on the internal use of therapeutic grade essential oils and the DANGERS and CAUTIONS to watch for when using essential oils for therapeutic versus aroma therapy.... of course anything I post is MY OPINION only. It is always best to do your own research and make your own decision what is best for you. I will include links and references.
You mention that you have tried many different natural healing modalities but did not give any specifics, so all I can do in response is give you some information and things to be watchful of when purchasing essential oils for therapeutic use.
Mountain Rose Herbs is a reputable website and they do sell quality herbs and products. I have never purchased essential oils from them however. They claim to have organic certification for many of their oils and also offer other details about their testing and distilling processes, however this is what I did find concerning how their essential oils are to be used:
As with all essential oils, never use them undiluted. Do not take internally unless working with a qualified and expert practitioner. I could not find any application information for specific essential oils, such as: apply topically, diffuse, directly inhale or take as dietary supplement.
And then this:
Mountain Rose Herbs essential oils are wholly suitable for aromatherapy, cosmetics, cooking and body application. (It does say "cooking", but not "dietary supplement or for internal use", so this could just mean that the spice and flavoring essential oils are suitable for cooking. I do not know.) I would consider oregano and thyme to be 'cooking' and/or flavoring oils, but again I do not know how they are graded with this company.
What I would do is contact Mountain Rose Herbs and ASK them if their oregano, mountain savory and thyme essential oils are safe to take internally and in a capsule. Oregano and thyme are 'hot' oils and do need considerable dilution, so keep that in mind if you plan to put them in a capsule.
I do have a thought on one other essential oil that may be of benefit for a bladder infection in addition to the three oils you have mentioned... JUNIPER. In "my opinion only" it is the top essential oil for any bladder issue. It is said to be: Antiseptic, digestive cleanser/stimulant, purifying, detoxifying, increases circulation through the kidneys and promotes excretion of toxins, promotes nerve regeneration. Some USES include: Liver problems, urinary/bladder infections, fluid retention.
Dr. Schulze the great herbalist says that eating juniper berries is one of the best plant/natural sources to heal any bladder issue, so if you can get fresh raw juniper berries to eat... just a thought.
I will say that I do take Young Living essential oils internally and that on MANY/MOST of their essential oil labels---right on the front under the name of the oil---it says ESSENTIAL OIL SUPPLEMENT--- on the side it says: For DIETARY, topical or aromatic use. It then lists the dilution for each use and how to dilute if putting in a capsule and any CAUTIONS. IThe best advice I can give you is that if you want to use an essential oil internally and are unsure if the oil is labeled as a dietary supplement check with the company BEFORE purchasing.
I hope this helps you.