Excerpt from Tired Thyroid - Reverse T3: Side effects of
T3-only (or why you need T4 too)...
"High reverse T3 (rT3) levels or a “bad” reverse T3 ratio (Free T3 divided by rT3 is less than 20) are said to be the cause of
stubborn hypothyroid symptoms even while one is takin
g an ample amount of
medication. If the ratio is less than 20, then the treatmen
t touted by some is to take 75-125 mcg of
T3 only split throughout the day, and no T4 whatsoever.