I have written a book detailing how people with lower back pain can potentially get pain relief (not a cure), but I believe advertising standards would prevent me from selling anything that offers "pain relief". How do I workaround this?
I think the problem is not in pain relief but in using the words healing if you don't have data. Relief is measureable yes, but its also very subjective to the person. Take in consideration Chiropractors (citychiropractor.com) or Magnetic Physiotherapists (magneticphysiotherapy.com) - these services provide relief and maybe some healing but theres always debate on the validity of it all.
If youre trying to sell a book, your problem wouldn't be FCC, it would be marketing it.
My name is Humberto, I'm the founder of www.unthink.me and evangelist of a 100 Software Engineer team called BetaBulls. I have brought products to Shark Tank, and helped some quirky products get to market as well as helped countless startups. I hope my answer provided at least minimum clarity to you. Happy trails and best of luck!
Perhaps you can flip it and market it as a book that helps people live with joy and physical comfort. Instead of focusing on the negative and treatment aspect, focus on the upside of how to live well and with pleasure.