Tired, Foggy, and ‘Normal’? Why Levothyroxine Alone Doesn’t Work for Everyone
- Bilal Mannan, MD
- 5 days ago
- 2 min read
Managing hypothyroidism isn’t always as simple as replacing a missing hormone.
Most people start with levothyroxine, a synthetic version of T4, which the body converts into the active hormone T3. For many, it works well. Energy improves. Brain fog lifts. TSH levels normalize.
But not for everyone.
Some people stay tired. Moody. Cold. They say, “My labs look fine, but I still don’t feel right.”
That’s when the conversation shifts to combination therapy—replacing both T4 and T3.
First, what is levothyroxine?
Levothyroxine is a fully synthetic form of thyroxine (T4). It’s manufactured through chemical synthesis in precise doses. It’s consistent, long-acting, and the standard treatment for hypothyroidism worldwide.
Most patients do well on it. But some don’t convert T4 to T3 efficiently—because of genetic variations, stress, inflammation, or other unknown factors.
That’s where T3-containing therapies come in.
Two paths: Synthetic Combo or Desiccated Thyroid
1. Synthetic T3 + T4
This approach pairs levothyroxine (T4) with liothyronine (T3), a synthetic version of triiodothyronine.
Allows precise control over dosing
No animal products involved
Easier to adjust based on labs and how you feel
But it’s not without its quirks. T3 works fast—some patients feel a burst of energy, even anxiety, if not dosed carefully. Timing and consistency matter.
2. Desiccated Porcine Thyroid
Brands like Armour Thyroid, NP Thyroid, and Nature-Throid are made from dried pig thyroid glands. They naturally contain T4 and T3 in a fixed ratio—about 4:1.
Some patients feel dramatically better on it. But there are a few things to consider:
The fixed T4:T3 ratio may not be right for everyone
Dosing can be less precise and harder to titrate
Batch variability is more common than with synthetics
It’s pork-derived—not suitable for everyone due to dietary, religious, or ethical reasons
It can be more immunogenic—meaning your body may be more likely to recognize it as foreign and trigger side effects or reactions
So while desiccated thyroid is “natural,” that doesn’t always mean safer or more effective.
So what’s right for you?
At Sina Health, we don’t take a one-size-fits-all approach. We:
Start with levothyroxine
Listen to your story, not just your labs
If needed, explore adding T3—either synthetic or desiccated—thoughtfully and collaboratively
The right treatment is the one that improves your well-being—not just your numbers.
If you’ve been told everything looks fine but you still don’t feel right, we hear you.
Let’s take another look—together.
For some with hypothyroidism, lab results look fine—but the symptoms linger. Here's why.
