Can You Take Milk Thistle With Candesartan?
A reader taking candesartan, a blood pressure medication, asks whether it is safe to also take a milk thistle supplement.
Can I take candesartan with a milk thistle supplement?
Jul 13, 2026- Milk thistle is not known to have a clinically significant interaction with candesartan based on how each drug works in your body.
- Since candesartan is only minimally processed by the liver, even if milk thistle affected liver enzymes, it wouldn't be expected to significantly change candesartan levels.
- It's still important to tell your pharmacist or doctor that you're taking milk thistle and to monitor your blood pressure readings when adding any new supplement.
Hello, and thank you for bringing your question to us!
Milk thistle is not known to have a clinically significant interaction with candesartan, and based on how each works in the body, an interaction isn't expected.
The combination hasn't been formally studied in a clinical trial, as far as I am aware, so it's still smart to let your pharmacist or doctor know you're adding it. However, there's nothing about these two that raises a red flag.
How Candesartan Is Processed in the Body
Candesartan (brand name Atacand) is an angiotensin II receptor blocker, or ARB, used to treat high blood pressure and certain types of heart failure. It's actually taken as a prodrug called candesartan cilexetil, which is converted to active candesartan as it's absorbed through the gut wall.
From there, candesartan undergoes only minor metabolism by the liver enzyme CYP2C9, and most of the drug is eliminated unchanged in the urine and bile.
This is a helpful profile because drugs that don't rely heavily on liver enzymes for their breakdown tend to have relatively few interactions with supplements, and candesartan falls into that category.
Milk Thistle Interaction Concerns
Milk thistle (Silybum marianum) is one of the most popular herbal supplements in the world and is best known for its purported liver-protective effects. Its main active constituent is silymarin, and most supplements are standardized to contain around 70% to 80% silymarin extract. You can read more about milk thistle on our website: Milk Thistle Drug Interactions, Uses, Side Effects & More | HelloPharmacist.
The usual interaction concern with milk thistle is that laboratory studies suggest silymarin may inhibit certain liver enzymes, including CYP2C9 and CYP3A4.
However, human studies using typical supplement doses have generally not shown meaningful changes in the blood levels of drugs that rely on these enzymes.
Since candesartan is only minimally metabolized by CYP2C9 in the first place, even a modest inhibitory effect wouldn't be expected to significantly change candesartan levels.
Final Words
Overall, milk thistle isn't expected to interact with candesartan, and there's no evidence suggesting that you need to avoid the combination.
Be sure to mention it to your pharmacist or doctor at your next visit so they can keep your records complete, and reach back out if you have any other questions. We're always happy to help!
References & sources
Glossary — Terms in This Answer
- ARB
- A type of blood pressure medication that blocks angiotensin II receptors in the body to help lower blood pressure.
- Prodrug
- A medication that is inactive when taken but gets converted into its active form inside the body.
- Metabolism
- The chemical process by which the body breaks down drugs and other substances so they can be eliminated.
- CYP2C9
- A liver enzyme responsible for breaking down certain medications in the body.
- Silymarin
- The main active ingredient in milk thistle that is believed to have protective effects on the liver.
- Inhibit
- To slow down or block the action of an enzyme or other body process.
- Standardized
- Adjusted to contain a specific, consistent amount of the active ingredient across different batches of a supplement.
- Bile
- A digestive fluid produced by the liver that helps break down fats and eliminate waste products from the body.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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