Liothyronine is a synthetic T3 thyroid medication that is bioavailable. Our bodies have to convert T4 medications (like Synthroid, Levothyroxine, Tirosint, and Natural Desiccated Thyroid (NDT) hormones) into T3 to be used in our cells. There isn’t a conversion process with Liothyronine because it acts directly. Cytomel is the name brand of T3 but there are also many generic brand options of Liothyronine available.
Most commonly, people take T3 when they are having an issue with converting T4 into T3. Their Reverse T3 goes up because of this, leaving one with hypo symptoms. Note that it is NOT always necessary to stop taking medications that contain T4 but to lower it to stop the conversion to Reverse T3 and add T3. There are some that need T3 only due to deiodinase enzyme mutations. The key to conversion issues is treating the things that are blocking conversion from happening in the first place. These issues can include high or low iron, high or low cortisol, EBV, Lyme and inflammation.
Reverse T3 can take 8-12 weeks to lower (once T4 has been lowered enough). Adding in a T3 medication slowly can begin to eliminate symptoms. This Reverse T3 does NOT cross into the nucleus very well and does NOT compete with triiodothyronine for its receptors. When Reverse T3 is high, we have symptoms of hypothyroidism. We usually see a low FT3 with high Reverse T3, hence the symptoms.
HOW DO I DOSE WITH T3?
Because T3 is direct and fast acting, patients report that they feel best dosing 3-4 times a day anywhere from 4-6 hours apart and some are able to go closer to 8 hours without issue. It seems the more hypo one is, they may need to keep dosing closer to the 4-6 hr. timeframe. Some find that after they have been on T3 for a while or are optimal that they can dose T3 anywhere from 1-3 times a day. Many find taking a little before bed helps with sleep and the body isn’t going too long in between doses which can stress the adrenals.
An initial dose would be 5-6.25 mcg (since many get 25 mcg pills). T3 is very powerful, and one may find that they need to start with 5 mcg split into two 2.5 mcg doses. It is then raised once a week until the elimination of symptoms and having labs that fall into a certain range. TSH and Free T4 will be suppressed and FT3 will be at the top of the range and sometimes over based on what patients have experienced once they became symptom free.
Can I dose T3 sublingually (under the tongue or in the cheek)? There are conflicting reports on dosing T3 sublingually. It’s clear that taking it sublingually gets T3 into a person’s system; what’s not clear is whether or not it’s any different from swallowing it. However, many patients report that they feel it does work sublingually because they dose it near supplements that it would otherwise bind with, (e.g. iron, calcium supplements, oral estrogen).
WHAT ABOUT SLOW RELEASE T3?
Overall, SR T3 does not work for most people. This is due to the fact that the cells need T3 to arrive quickly – all at once – to be able to overcome any cellular resistance. The SR T3 is slow in it’s arrival to the cells and often give peaks and valleys of response. Also, we have found that patients need healthy guts and good levels of stomach acid to be able to break down the slow release component.
This video explains about RT3, as well:
https://youtu.be/ol16BZqVM48
Metabolic effects of liothyronine [T3] therapy in hypothyroidism: a randomized, double-blind, crossover trial of liothyronine [T3] versus levothyroxine [T4]
http://www.ncbi.nlm.nih.gov/pubmed/…
For information on various allergens (gluten, lactose, cornstarch) in t3 medications: Always check with the manufacturer for up-to-date information! Obviously, those with Celiac Disease wouldn’t want to take any gluten. But for those with Non-Celiac Gluten Sensitivity, it depends on the individual when it comes to whether or not they can take medications with gluten in them. In other words, some with NCGS report being able to take gluten-containing thyroid medications with no problems, while others cannot. We do have information on the most popular T3 medicines on our Ingredients page.