Years ago, we as hypothyroid patients due to any cause, noticed a phenomena we call pooling. It means T3 going high in the blood and not making it to the cells. Thus continued hypo symptoms, but many experienced hyper-like symptoms from the pooling. It’s usually due to a cortisol problem, whether too low or too high cortisol. Check out the information below and see what you think. ~Janie, hypothyroid patient and site creator.

Pooling means your free T3 isn’t making it well to your cells, and instead, is hanging out in your blood, going higher and higher as you raise your T3-containing medication like Cytomel (T3) or are on a working natural desiccated thyroid.

Why does pooling happen?

Pooling is always associated with having a cortisol problem. It mostly happens with having low cortisol, but can also happen with a mix of highs and lows, or mostly highs. When cortisol is off, it can’t distribute T3 to the cells well. So the T3 goes high in the blood with continued symptoms.

What are symptoms patients experience due to pooling, which pushes excess adrenaline?

They are individual. Some people notice nothing. Some notice increased hypothyroid symptoms, which can include fatigue, depression, etc. Others notice hyper-like symptoms such as anxiety, panicky feeling, jittery, shakiness, heart palps, higher heartrate, higher blood pressure, etc.

How have patients figured out they are pooling??

Exactly as explained above under the heading “Why dose pooling happen”.

First, especially on a dose of T3 that’s not very high, you may see a free T3 towards the top of the range or even way over range...YET, there will be continued symptoms of hypo or for some, symptoms of excess adrenaline/hyper-like for others. So though it “looks” optimal, it may actually be pooling.

Or we may see a high-in-the range T3 (or over) with a free T4 that’s lower in its range, especially if you are on desiccated thyroid–the latter can be common, too, for pooling.

What causes pooling and what have patients done about it?

For most hypothyroid patients, the causes are pretty clear: inadequate levels cortisol first and foremost, usually too low cortisol, but can happen with a mix of highs and lows, and even all high. So we realize either of those will need to be discovered and treated. We find that the best way is doing a saliva cortisol, which is measuring what is available and unbound. Blood on the other is measuring what’s bound and unavailable and we have seen blood results to not always fit what our symptoms tells. Plus a blood cortisol test is only at ONE TIME, and you miss what’s going on at other times. You can click below to order a saliva cortisol test.

When you get your saliva results

When you get your lab results back, compare them to the information on the lab values page. The latter is based on where patients fall who don’t have a problem. This may be information you’ll have to teach an open-minded medical professional.

Do pooling and a high Reverse T3 come together?

They can, but usually only if you also have “high” cortisol in your saliva results. Two other causes of rising RT3: Inflammation and low iron

If I have no symptoms of pooling, yet it’s very clear with labs, do I not have a problem?

Patients still see a problem and need to treat the pooling, we’ve discovered, which is usually always about a cortisol issue.

My doctor wants me to move back over to T4-only, claiming the T3 in NDT is just too much for me, thus why it’s high. Is that the solution?

Beware: doctors don’t get pooling at all or what causes it!! So they tend to send us back to an inadequate treatment with T4-only. But we found it’s NOT the solution and only makes the reasons for your pooling WORSE.

What is the treatment solution for pooling, say patients?

First and foremost, patients report learning over the years to treat the causes of pooling by ordering a 24 hour adrenal saliva test, since low cortisol is a main reason, but high cortisol can do it, too!!  A cortisol test for us is never blood testing!

In the meantime…

a) Some do fine keeping the pooling as it is, as long as we don’t have bad symptoms, or aren’t getting ready to start on cortisol…but they still need to discover and treat the causes. If you start on cortisol with pooling, that high Free T3 will rush into your cells like a son-of-a-gun and give horrible hyper.

b) Others go down on their NDT or T3 if they notice hyper-like symptoms. They will go down sometimes more than half, allowing the pooled T3 to fall, and which can happen within a week if lowered enough…and may take longer to fall if one is only on NDT. Patients then report they can add back in a small amount of straight T3 (i.e. T3 to the lowered NDT they were now on, or T3 to the smaller amount of T3 they were now on), and raise in small increments to alleviate symptoms of hypo. How much added T3? 10 mcg T3 is a good starting dose to add back in, or half a 25 mcg tablet to equal 12.5 mcg if you only have the larger tablets. As symptoms of hypo return, patients may add smaller increments of T3. But it’s important to remember that your T3 will pool again if you haven’t treated the reasons for it, which is about a cortisol problem, so judicious use of the added T3 is important.

c) It becomes important to lower the high FT3 when getting ready to start on cortisol. This is a hard-earned lesson–that if we start on cortisol with high levels of FT3, the cortisol will enable those high levels to get to the cells…except there is SO much due to pooling, we end up with the worst hyper from hell as the excess T3 enters our cells. So we lower the FT3 before starting on cortisol by lowering whatever thyroid meds we are on. Sometimes just a few days on a lower amount is enough. Work with your doctor on this.

Bottom line

We’ve learned how very important it is, before raising a working NDT or T3, to see where our adrenals stand by comparing the results to the Lab Values page, then treating if we see a problem. Treatment of a cortisol problem is completely explained in chapters 5 and ESPEICALLY chapter 6 of the updated revision STTM book.

This research explains the “altered interaction between T3 and cell receptors:

**Read more about IRON AND CORTISOL. It’s important. 


Important note: STTM is an information-only site based on what many patients worldwide have reported in their treatment and wisdom over the years. This is not to be taken as personal medical advice, nor to replace a relationship with your doctor. By reading this information-only website, you take full responsibility for what you choose to do with this website's information or outcomes. See the Disclaimer and Terms of Use.