Dr. Ken Blanchard, endocrinologist and doctor for 40 years, in his book, What Your Doctor May Not Tell You About Hypothyroidism, summarizes his protocol after treating of thousands of hypo patients:

Today I have a compounding pharmacist weigh out natural thyroid extract and put it into time-release capsules. I always prescribe synthetic T4 to balance the ratio in order to achieve 98 percent T4 and 2 percent T3.