Short answer: NIDDK says "Hypothyroidism can contribute to high cholesterol. If you have high cholesterol, you should get tested for hypothyroidism." MedlinePlus uses the same words: "Hypothyroidism can contribute to high cholesterol." An American Thyroid Association summary of a study of over 11,000 US adults says hypothyroidism was associated with higher cholesterol levels, particularly in those with more moderate or severe hypothyroidism. The National Heart, Lung, and Blood Institute (NHLBI) puts hypothyroidism on its list of conditions to talk to your healthcare provider about when it comes to your risk of high cholesterol. NHLBI also says an unhealthy lifestyle is the most common cause of high LDL cholesterol, and that genes and other medical conditions may also raise LDL cholesterol levels. What your own numbers mean is a conversation for your doctor.
If your cholesterol came back high and nobody mentioned your thyroid, or you have Hashimoto's and a lipid panel just landed in your portal, this is for you. You're allowed to ask how the two fit together. The useful move is to walk in with both reports and the right questions.
Osmi's lab album keeps your thyroid results, each on its own card, shown against the range your own lab printed. You photograph the paper, upload the PDF, or type one number, and each value is saved with the day the blood was drawn and the name of the lab. Osmi doesn't diagnose anything, and it doesn't have a range of its own.
What the US sources say about thyroid and cholesterol
Each body says it a little differently, and the verb matters as much as the link.
| Source | What it says | How it scopes it |
|---|---|---|
| NIDDK, hypothyroidism page | Hypothyroidism can contribute to high cholesterol; if you have high cholesterol, get tested for hypothyroidism | Uses "can contribute"; listed under complications |
| NIDDK, Hashimoto's page | Many people with Hashimoto's develop hypothyroidism, and untreated hypothyroidism can lead to health problems including high cholesterol | "Untreated"; it names heart disease and heart failure on the same list |
| MedlinePlus, hypothyroidism page | Hypothyroidism can contribute to high cholesterol | Listed under other problems hypothyroidism can cause |
| MedlinePlus, high cholesterol encyclopedia page | Some health conditions can also lead to abnormal cholesterol levels, including an underactive thyroid gland | One of several conditions, next to diabetes, kidney disease and pregnancy |
| NHLBI, cholesterol causes page | Talk to your healthcare provider about your risk of high cholesterol if you have hypothyroidism | Lifestyle is the most common cause; hypothyroidism is one condition on a list |
| Cleveland Clinic, hypothyroidism page | Elevated blood cholesterol levels are on its list of possible symptoms | Uses "possible"; it says symptoms usually develop slowly |
| ATA, 2017 study summary | Hypothyroidism, particularly if moderate or severe, was associated with increased cholesterol levels | One study of over 11,000 US adults, summarized |
Two framings sit side by side there. NIDDK and MedlinePlus file high cholesterol under problems hypothyroidism can contribute to. Cleveland Clinic lists it among possible symptoms.
Hashimoto's comes in through hypothyroidism. NIDDK says Hashimoto's disease is the most common cause of hypothyroidism, and its Hashimoto's page puts high cholesterol on the list of problems untreated hypothyroidism can lead to.
The heart is where the sources differ in scope. The MedlinePlus encyclopedia says people with untreated hypothyroidism are at increased risk of heart disease because of higher levels of LDL cholesterol. The ATA's 2017 summary, of one US study, found higher cholesterol with hypothyroidism but no significant differences in heart attacks or strokes based on thyroid function alone. That's a question for your doctor, with your own history in front of them.
Why the two tests can turn up on the same lab order
The sources describe the two tests from both directions.
From cholesterol to thyroid: NIDDK says that if you have high cholesterol, you should get tested for hypothyroidism. NHLBI says your provider diagnoses high blood cholesterol from your medical and family history, a physical exam and a blood test, and that during the exam they check for signs of other health conditions that can cause high blood cholesterol.
From thyroid to cholesterol: the MedlinePlus encyclopedia says that when hypothyroidism is being looked into, blood tests measure free T4 and TSH, and you may also have tests to check cholesterol levels.
So if both tests are on one order, that's in line with what NIDDK and MedlinePlus describe. For the rest of what can sit on that order, see the other blood tests worth asking about.
One practical thing. MedlinePlus says you may need to fast for 9 to 12 hours before a blood cholesterol test, which is why those tests are often done in the morning. For a TSH test, it says that if your provider has ordered other blood tests, you may need to fast for several hours first. Your provider will tell you what applies, so ask when the order goes in.
What each test measures
The TSH test measures thyroid-stimulating hormone. MedlinePlus says a TSH test can't show what is causing a thyroid problem. For the wider set of thyroid markers, see the full thyroid panel.
The lipid panel, also called a lipoprotein panel or lipid profile, measures your LDL and HDL cholesterol and your triglycerides, per NHLBI.
What you can compare against is the range printed on your own report and what your provider tells you about it. Osmi has no cholesterol cut-off of its own. MedlinePlus says to talk with your provider about what your cholesterol numbers should be, and that the numbers that are best for you may depend on your age, race, blood pressure, weight, family history, and more.
What to bring, and what to ask
NIDDK says hypothyroidism develops slowly, so you may not notice symptoms for months or even years, and Cleveland Clinic says its symptoms usually develop slowly over time. Dates help. Bring:
- Both reports, the lipid panel and the thyroid results, with the date each blood draw happened.
- Whether you fasted before each draw.
- Your family history of high cholesterol and thyroid disease. NHLBI says your medical and family history is part of how high cholesterol is diagnosed.
- How you've been feeling, written down with dates. NIDDK says a hypothyroidism diagnosis can't be based on symptoms alone, so the dates go with the labs, not instead of them.
Then ask:
- My cholesterol came back high. Has my thyroid been checked?
- Were these two results from the same draw?
- Did either test need me to fast, and did I?
- What should my cholesterol numbers be, given my age and family history?
- I have Hashimoto's. Does that change what you look at?
- When would you want to repeat each test?
Osmi's daily check-in takes about a minute: answer seven questions or speak with Rose, your thyroid mascot, and every answer lands on the same record as your labs, cycle, and sleep. When it's time to go in, the appointment sheet is one page, built from the record you already keep, that you share with your practitioner in one tap. It doesn't diagnose anything and it doesn't read your results for you. For the rest of the visit, see walk into your thyroid appointment with a real record.
What your results mean together, and what to do next, is your doctor's call. One small thing for today: put both reports in the same folder, with their dates.
Questions women ask about hypothyroidism and cholesterol
Can hypothyroidism cause high cholesterol? NIDDK and MedlinePlus both say hypothyroidism can contribute to high cholesterol. The MedlinePlus encyclopedia lists an underactive thyroid gland among health conditions that can also lead to abnormal cholesterol levels. NHLBI says an unhealthy lifestyle is the most common cause of high LDL cholesterol, and that other medical conditions may also raise it.
Can Hashimoto's raise your cholesterol? NIDDK says many people with Hashimoto's disease develop hypothyroidism, and that untreated hypothyroidism can lead to several health problems, including high cholesterol. NIDDK also says Hashimoto's disease is the most common cause of hypothyroidism. Ask your doctor how your own thyroid results and cholesterol results fit together.
Is high cholesterol a symptom of hypothyroidism? Cleveland Clinic lists elevated blood cholesterol levels among possible symptoms of hypothyroidism. NIDDK and MedlinePlus describe it differently, as something hypothyroidism can contribute to. Either way, NIDDK's advice is that if you have high cholesterol, you should get tested for hypothyroidism. Bring both results, with the date of each draw.
Should I get my thyroid checked if my cholesterol is high? NIDDK says that if you have high cholesterol, you should get tested for hypothyroidism. NHLBI lists hypothyroidism among the conditions to talk to your healthcare provider about when it comes to your risk of high cholesterol. Ask whether a TSH test has been done, and when.
Do I need to fast for a thyroid and cholesterol blood test? MedlinePlus says you may need to fast for 9 to 12 hours before a blood cholesterol test. For a TSH test, it says that if other blood tests have been ordered, you may need to fast for several hours. Your provider will let you know if you need to fast.
What cholesterol number is too high if you have hypothyroidism? MedlinePlus says to talk with your provider about what your cholesterol numbers should be, and that the numbers that are best for you may depend on your age, race, blood pressure, weight, family history, and more. Osmi doesn't set a number. Bring the range printed on your own report and ask.
Educational, not medical advice.
