Key takeaways:
Most supplements before a cholesterol test won’t interfere with the results. But, just to be safe, you may want to avoid certain B vitamins and fish oil.
Not everyone has to fast before a cholesterol test. Unless you have high triglycerides, eating before the test doesn’t make much difference.
Skip heavy, fatty foods as well as alcohol before a test. Also, avoid doing strenuous workouts to get the most accurate cholesterol reading.
Scheduling a cholesterol test used to come with a strict list of rules — like skipping breakfast and your morning coffee. People are still told they can have nothing but water until you get your blood drawn. And if you have a morning supplement regimen, that can make things even more confusing.
Recent research has debunked many of these testing myths. And despite what many people think, you may not have to hold your supplements, either. Here’s what you need to know about taking supplements before a cholesterol test.
Can you take supplements before a cholesterol test?
In most cases, you can continue taking your usual supplements before a cholesterol test. This is true whether you take your supplements in the form of pills or powders mixed into food.
You read that right — you might not even have to take the test on an empty stomach. More recent research shows that fasting doesn’t make a significant difference in the results. A study of 4,100 people found that levels of low-density lipoprotein (LDL) or “bad” cholesterol were only about 4 mg/dL higher in people who ate before their test.
However, this isn’t the case for everyone. People with high triglyceride levels should fast after dinner the night before their test. Triglycerides — like cholesterol — are a type of fat in the blood that can raise your risk of heart disease. They are normally tested alongside cholesterol. And eating before getting blood drawn can lead to results showing high triglyceride levels. So if you’re not sure if your triglycerides are high, it’s probably safer to follow fasting instructions.
What supplements should you avoid before a cholesterol test?
Some people think that certain supplements can skew a cholesterol test. Examples include niacin (vitamin B3), biotin (vitamin B7), and fish oil and omega-3s. But there’s actually no research that shows these supplements interfere with cholesterol tests.
Some research shows that supplementing with certain vitamins and nutrients may help lower cholesterol levels. But these changes take time, and you have to be consistent with taking your supplements every day.
But it may be helpful to know that supplements can affect the results of other blood tests — tests that you may be having done at the same time as cholesterol tests. B vitamins, especially biotin, can skew thyroid tests and troponin tests (a blood test that helps diagnose heart problems). And calcium supplements can give inaccurate results on a bone density test. This is important to keep in mind if you’re getting multiple tests done on one blood draw.
If you take supplements, it’s always a good idea for your healthcare team to have these on file for you. This will also make it easier for them to give you guidelines about the best way to take your medicines and supplements before blood tests.
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When should you stop taking supplements before a cholesterol test?
For most people, there’s no need to stop taking supplements before a cholesterol test. But if you have high triglycerides or a heart condition, ask your healthcare team if you should skip any supplements in the day or two before the test. They may want to see your results without certain supplements in your system. They may also ask you to fast before the test, which means not consuming anything but water for 8 to 12 hours prior.
What else can interfere with cholesterol test results?
Generally, eating something small before a cholesterol test won’t affect the results much. But other things might. It’s best to avoid the following things in the 24 hours before your test:
A big, high-fat meal
Alcohol may interfere with a cholesterol test. So consider skipping pouring a drink 24 hours before getting your blood drawn.
Strenuous cardio workouts may cause your levels of LDL cholesterol to spike in the short term. Rigorous exercise may boost free radicals, which can briefly raise or alter levels of LDL or “bad” cholesterol.
Certain medications might also cause skewed results. These medications include steroids, hormone treatments, and medications used to treat HIV, seizures, and psychosis.
The bottom line
Taking supplements before a cholesterol test is unlikely to affect the results. Still, if you take any supplements, discuss them with your primary care provider when you schedule your cholesterol test. That’s especially important if you have a medical condition and you’re taking medication. At the same time, you can also ask your healthcare team if you need to fast beforehand. This recommendation is common, but it’s not always necessary.
Why trust our experts?
References
Darras, P., et al. (2018). Nonfasting lipid testing: the new standard for cardiovascular risk assessment. Canadian Medical Association Journal.
Herink, M. C. (2025). Medication induced changes in lipids and lipoproteins. Endotext.
Ignite Healthwise. (2025). Cholesterol and triglycerides tests. Kaiser Permanente.
Krueger, D., et al. (2006). Calcium supplement ingestion may alter lumbar spine bone mineral density measurement. Journal of Clinical Densitometry.
Rahnama, N., et al. (2009). A 90 minute soccer match decreases triglyceride and low density lipoprotein but not high-density lipoprotein and cholesterol levels. Journal of Research in Medical Sciences.
U.S. Food and Drug Administration. (2019). FDA in Brief: FDA reminds patients, health care professionals and laboratory personnel about the potential for biotin interference with certain test results, especially specific tests to aid in heart attack diagnoses.
