06/15/2026
Taken from The Thyroid Health Project:
“I've read too many cardiac autopsies to not share this with you. If you have Hashimoto's, I need to tell you something your endocrinologist isn't seeing.
I've reviewed 5,800+ cardiac cases in 19 years as a cardiologist.
When a woman walks into her endocrinologist's office for her annual Hashimoto's check, I already know what her cardiac imaging will show 5 to 10 years before she ever feels chest pain.
Her heart is starving.
The same problem causing her weight gain and her fatigue is silently weakening her heart muscle right now.
I'm Dr. Helen Marshall. Cardiologist. 19 years.
When I was diagnosed with Hashimoto's at 47, I knew something endocrinologists never tell their patients.
Your Hashimoto's isn't a thyroid problem. It's a system-wide problem. And your heart is on the list.
Endocrinologists test your TSH. Adjust your pill if it drifts. Send you home.
They don't see you 5 to 10 years later when you're in my cath lab with crushing chest pain.
But I do.
The 54-year-old. Levothyroxine for 14 years. TSH always 2.1. Doctor pleased with her at every appointment. Came in last spring out of breath climbing the stairs at her grandson's birthday party. Her echocardiogram showed early heart failure. I ordered a Free T3. It came back at 1.6. The bottom of the lab range is 2.0. Her heart had been starving for years while her endocrinologist kept telling her she was managed.
The 49-year-old. "My numbers are perfect, doctor." Levothyroxine for 9 years. Came to me with chest pain. Coronary calcium score of 287. Severe disease for her age. Bypass surgery three weeks later. Her T3 had been below normal the entire nine years her TSH read fine. Her endocrinologist had never run a T3.
I see them in follow-up. They're grateful I "saved" them.
But I know what they lost.
They had years to fix this. Years to feed their hearts the active hormone they actually needed. Years to save themselves from surgery.
Their bodies were screaming the warning. The TSH test couldn't see it. A higher Levo dose couldn't fix it.
My own labs told me what I already suspected.
22 pounds in two years on the same diet. Cold hands. Brain fog at 3 PM I was calling "long days." Resting heart rate climbing.
My endocrinologist looked at my chart. "Standard protocol. Levothyroxine 50 micrograms. Recheck TSH in 8 weeks. We'll adjust."
The dose adjustment would have normalized my TSH. That wasn't the point.
I'm a cardiologist. I ordered my own Free T3 and a coronary calcium scan.
Free T3 of 1.9. Calcium score of 38. Plaque starting to build.
A higher Levo dose would have raised my T4 number while leaving my heart starving for the T3 it actually used.
Here's what endocrinologists don't tell you, because they don't see what I see.
Your heart muscle runs on T3. Not T4.
T4 is the storage form. Your thyroid releases it. Your pill replaces it. Your liver has to convert T4 into T3 before your cells can use it.
If your liver isn't doing that conversion, your blood looks fine. Your TSH looks fine. Your endocrinologist tells you you're managed.
But your heart is going cold.
For years. Sometimes decades.
You're not "getting older." You're not "going through menopause." You're not "stressed."
Your cells are starving. Your heart muscle is weakening. The same problem causing your weight gain is happening in your cardiac tissue.
Right now.
Your soft tissues fail first because they're forgiving. Your heart muscle is harder to break. By the time it breaks, the warning has been screaming for years.
Women with Hashimoto's are 17 times more likely to die of a heart attack before 70 than women without it.
Not twice. Not 5 times. 17.
Your Hashimoto's isn't an inconvenience. It's an early warning. And a higher Levo dose silences the warning while your heart deteriorates.
I tried what patients try.
AIP diet for six months. Helped my labs slightly. My T3 stayed under 2.0.
Selenium. Zinc. Iodine. No change.
A combination T3/T4 protocol for four months. My anxiety spiked. My heart rate climbed. My cellular T3 still didn't normalize. I stopped.
Nothing was reversing the conversion failure.
But I kept thinking about something that made no sense. The pathway that converts T4 into T3 lives in your liver. The research is clear: when the liver heals, the conversion comes back.
So why wasn't mine?
March 12th. 11:43 PM.
I was reviewing journals after a late shift. Couldn't sleep. The fatigue was getting worse.
I came across a study on cold-processed milk thistle and the liver's conversion pathway.
I'd never connected the two.
Here's what stopped me cold.
"Cold-processed milk thistle plus the right minerals restored thyroid conversion in 71% of patients with chronic hypothyroidism over 12 weeks."
Not raised. Restored.
I sat there at 11:43 PM staring at it.
Levothyroxine is wood. It arrives every morning. If your liver can't burn it, the heat never reaches your heart. Your TSH reads normal because the wood is there. Your endocrinologist is pleased. But your heart is freezing.
Cold-processed milk thistle opens the flue. Your liver heals. The wood actually burns. The heat reaches your heart.
I'd been a cardiologist for 19 years and I'd never seen the explanation laid out that simply.
Because endocrinologists don't study the liver. And cardiologists don't typically treat Hashimoto's.
The gap is real. And it's where women like me are dying.
At 12:09 AM, I ordered cold-processed milk thistle with the cofactor minerals.
I started March 13th. Twice daily, with meals.
March 16th. 3 days in.
I woke up warm. Hands warm. Feet warm. My hands had been cold for two years.
I lay there testing it. Thinking it was psychological. It wasn't.
March 19th. 6 days in.
Down 3 pounds. The 3 PM fog didn't hit. I worked straight through to 6 PM. First time in 14 months.
My husband looked at me at dinner. "What's different?"
"Different approach," I said.
"Whatever you're doing, keep doing it."
March 25th. 12 days in.
Down 7 pounds. Resting heart rate dropped from 86 to 76. Energy back to my baseline from five years ago.
But I wanted proof this was system-wide.
May 9th. 8 weeks in.
Follow-up Free T3, lipid panel, calcium scan.
I positioned myself for the scan. Waited for the images.
When they came up, I stared at the screen for a full minute.
Free T3 at 3.2. Optimal range for the first time in two years.
Coronary calcium score reduced from 38 to 24.
37% calcium reduction in 8 weeks.
LDL down 41 points.
My Hashimoto's was reversing because my flue was opening.
Not raised. Healed.
I printed both scans. Walked down to my colleague's office.
Dr. Patricia Reeves looked at the images. Looked at me. Looked back at the scans.
"Helen. What did you do? Calcium scores don't drop this fast."
I explained the milk thistle. The minerals. The liver pathway.
She studied the scans for another minute.
"Your Free T3 normalized. Your calcium score dropped 37%."
"Yes."
She was quiet for a moment. "I need to start running Free T3 panels on every Hashimoto's patient I have. Not just TSH."
I'm not telling you this because I'm against Levothyroxine.
It saves lives. It restores T4 levels. It works exactly as designed.
But it doesn't open your flue.
It doesn't fix your conversion. It doesn't get T3 to your heart muscle. It raises your T4 while your liver fails to use it.
And I see what happens 5 to 10 years later when those women become cardiac patients.
Your Hashimoto's isn't failing you. It's warning you.
The same conversion problem starving your tissues is starving your heart muscle right now.
You have two choices.
Mask the warning with a higher Levo dose while your heart deteriorates.
Or open the flue.
I think about what I almost did.
I almost let my endocrinologist raise my dose every two years for the next two decades while my heart silently starved.
I almost became the patient I see in my cath lab 5 to 10 years later, wishing someone had told them their Hashimoto's meant something bigger.
Once you need cardiac intervention, you're on medications for life.
Once you have a heart attack, the damage is permanent.
Once you need bypass, your life changes forever.
You don't get a second warning.
Hashimoto's is your first warning. The only warning you can still act on.
Every woman I see in my cath lab with advanced disease and a Hashimoto's history says the same thing.
"I wish someone had told me my thyroid was connected to my heart."
I'm telling you now.
Fix the conversion. Save your metabolism. Save your heart.
Or normalize the TSH only. Risk everything.
Eight weeks.
That's how long it took to bring my Free T3 to optimal, drop my calcium score 37%, and reverse two years of cardiovascular drift.
Eight weeks of opening the flue instead of raising the dose.
Your Hashimoto's is giving you years of warning.
Use them.
- Dr. Helen Marshall, MD, FACC Cardiologist, 19 years Board Certified in Cardiovascular Disease
P.S.
If you're on Levothyroxine for Hashimoto's and you haven't had a Free T3 run in the last year, get one. Then try milk thistle for 8 to 12 weeks. Get the labs again.
You can always go back to a higher dose if it doesn't work.
But you can't undo cardiac damage if your warning system tried to save you and you silenced it with another pill.”
Pureveen
