@Iryna Klevetenko please read through our Symptom Dictionary handout on “Arthritis”. It’s important to address the root cause and this handout shares specific risk factors for the different types including Rheumatoid Arthritis (RA), which is an autoimmune condition.
Given that fact, I would look at prioritizing digestion and gut health, optimize vitamins A, D, and zinc (check levels), and strongly encourage a KBMO test to eliminate foods causing inflammation. In the absence of testing, eliminating dairy, gluten, grains, and nightshades for at least 4-6 months (or more if needed) will help while working on healing the gut lining.