Guides
Sustained-Release T3 vs Cytomel: What the Doctor's Manual Says
August 15, 2026 · Wilson's T3 Editorial
Two things are both called “T3”. One is the liothyronine tablet on the market (Cytomel). The other is the same hormone compounded by a pharmacist with a slow-release agent, which is what the WT3 protocol is built around. Doctors and patients ask about the difference constantly, and the doctor’s manual answers it in detail. This guide gathers those passages.
The two preparations
There are two types of T3 preparations. One is traditional liothyronine (e.g., Cytomel ) which is not sustained-release. The other is a T3 preparation compounded to incorporate a sustained-release agent (HPMC) used in many of the sustained-release medications on the market.
— Timing of Doses, Compliance, the doctor’s manual
The patient-facing page puts the same distinction in plainer terms:
The T3 medicine that is currently on the market (Cytomel) is instant release. But Dr. Wilson and other doctors prefer using T3 that has been mixed with a sustained-release agent for Wilson’s T3 therapy. This appears to be best accomplished by skilled and experienced pharmacists with specialized equipment.
— Sustained-Release T3 for Wilson’s Temperature Syndrome
Why the difference matters to him: steadiness
The manual’s argument is about how evenly T3 reaches the cells:
I believe that T3 compounded with a sustained release agent like that used in many sustained-release medications on the market, does a much better job at approaching this than does traditional, or instant-release T3 therapy (e.g. Cytomel).
It is clear that with T3 therapy for Wilson’s Temperature Syndrome, steadiness is everything. It has also become clear that the skill, care, and consistency with which the pharmacist makes the compound is crucial (this is even more so the case with T3 than it is for other compounded drugs that incorporate a sustained-release agent), and that the abilities and interests of compounding pharmacists are not all the same, so some care should be taken in selecting one.
— Timing of Doses, Compliance, the doctor’s manual
The story behind the switch
Dr. Wilson started with Cytomel. The reason he stopped is told on the treatment page:
When Dr. Wilson first started treating Wilson’s Temperature Syndrome, Cytomel (instant release) was all he used. When he had about 300 patients at a time on Cytomel, he would get about 6-8 beeper (technology before cell phones) pages over the weekend from patients having complaints and 2-3 of those calls would be about some pretty worrisome side effects. When Dr. Wilson thought of and started using T3 mixed with a sustained-release agent (see Wilson’s Temperature Syndrome history) he would go 6 months without a page.
— Sustained-Release T3 for Wilson’s Temperature Syndrome
The manual describes how the compound was tuned, dose by dose, against what patients reported:
When I first began using the HPMC compound, designed to be taken every 12 hours, the patients reported significantly better results than with traditional T3.
I asked how well and how long the doses seemed to work. Quite a few patients noted that the medicine seemed to begin wearing off about 30 minutes before the next dose. So I asked the pharmacist to increase the preparation’s concentration of HPMC. Then, many reported that it seemed to last until about 15 minutes before the next dose. So the concentration of the HPMC polymer in the capsules was increased again. Many patients reported it seemed to begin wearing off about 5 minutes before the next dose. So the concentration of the HPMC polymer was increased again, until finally, it seemed to last 12 hours based on clinical observation.
— Timing of Doses, Compliance, the doctor’s manual
What “sustained-release” does and does not mean here
A point of honesty from the manual itself, worth repeating because it is easy to overstate:
Note: You may have noticed that I have not called this compound “sustained-release T3.” Officially, a drug is not said to be sustained-release or time-release until blood studies have demonstrated such delivery according to FDA guidelines.
— Timing of Doses, Compliance, the doctor’s manual
So the phrase, as used on this site, describes the compounding method and clinical observation, not an FDA-established release profile.
The 12-hour rule
If the compound is designed around a 12-hour interval, the interval has to be kept:
The sustain-release technology available now is very good but it is not perfect. But nevertheless, very satisfactory results can be obtained if the T3 compound (designed to be taken every 12 hours), is taken as well on time as it can be taken-not even 3 minutes late.
It is true that about 6% of patients seem to do better when they don’t take their doses so much on time, or when they use Cytomel instead of the T3 compound I recommend (p112), but by far most patients do better when they are taking the T3 compound very much on time.
— Timing of Doses, Compliance, the doctor’s manual
And a practical note from the treatment page: the capsules are usually taken twice a day, with a full glass of water, “since the sustained-release system operates by way of ongoing hydration of the capsule”. They are prescribed by doctors.
His own estimate of the difference
Dr. Wilson makes a striking claim about the two preparations. It is his clinical impression, and he labels it as such:
Subjectively, I feel the compounded T3/HPMC preparation is about 20 times more effective in the treatment of Wilson’s Temperature Syndrome, while the incidence and severity of side effects is about 20 times less as compared to traditional T3.
— Timing of Doses, Compliance, the doctor’s manual
There is no controlled comparison behind that number; the protocol’s published record is small and is described honestly on the objection hub.
Choosing the pharmacy
Because the compound is made to order, the pharmacist is part of the treatment:
Pharmacies that make prescription medicines as well as sell those that are made by pharmaceutical companies are called compounding pharmacies. They can make (compound) T3 with a sustained-release agent.
It’s important for compounded T3 to be mixed thoroughly: V blenders and acoustic mixers work well
When you use the T3 in sustained release form, the WT3 protocol works much better, with fewer side effects. Sustained release T3 is compounded by pharmacists. The pharmacy you choose can affect the treatment’s efficacy since not all pharmacists have the same knowledge, experience, equipment, or skill.
— Compounding Pharmacies for Wilson’s Temperature Syndrome
The pharmacies Dr. Wilson has worked with in the United States, Canada and South Africa are listed on that page, and the practitioner-side list is at Sources of Sustained Release T3.
For doctors
The full reasoning — including the pharmacology of the HPMC matrix and what to do when a patient is one of the 6% — is in the manual chapter Timing of Doses, Compliance, and the protocol itself in Treatment Principles. Dr. Wilson’s staff offer free technical support to prescribing physicians; details are on the For Doctors page.
This is a reader’s guide compiled from Dr. Wilson’s published writing; every quotation is his and links to its source. T3 is a prescription medicine; nothing here is a dosing instruction or medical advice.