Safety guide
Berberine and Your Medications: What to Check Before You Start
Berberine can change how some medicines work. It may raise cyclosporine and tacrolimus levels, and it slowed three enzymes that break down many common drugs (MSK About Herbs: berberine). A berberine herb also lowered metformin levels in one study (NCCIH: goldenseal and berberine). It is not for pregnancy or breastfeeding. Show your pharmacist the full Slim Metrix label before your first capsule.
Written by the Slim Metrix editorial teamUpdated · 7 min read
How it happens
Why does berberine interact with medicines?
Berberine slows some of the liver enzymes your body uses to clear drugs. When those enzymes slow down, a medicine can build up in the blood and act stronger than your doctor planned.
Memorial Sloan Kettering reports that berberine lowered the activity of three of these enzymes in people: CYP2D6, CYP2C9 and CYP3A4 (MSK About Herbs: berberine). Many everyday prescriptions rely on them. Your pharmacist can look up which of yours do.
Tell every provider about each supplement you take (NCCIH: using dietary supplements wisely).
The list
Which medicines interact with berberine?
Transplant drugs, metformin and drugs cleared by CYP enzymes top the list. Other Slim Metrix ingredients touch some of the same medicines.
| If you take | What berberine may do | Other Slim Metrix ingredients involved |
|---|---|---|
| Cyclosporine or tacrolimus | May raise their blood levels (MSK About Herbs: berberine) | Cayenne may raise cyclosporine levels (MSK About Herbs: cayenne) |
| Drugs cleared by CYP2D6, CYP2C9 or CYP3A4 | Slowed these enzymes in people (MSK About Herbs: berberine) | Resveratrol changed them at 1 g a day (MSK About Herbs: resveratrol) |
| Metformin | A berberine herb, goldenseal, cut metformin levels about 25% (NCCIH: goldenseal and berberine) | Chromium may add to its glucose-lowering effect (NIH ODS: chromium fact sheet) |
| Insulin or other diabetes medicine | No direct interaction is listed in these sources | Chromium, alpha-lipoic acid and ginseng may add to it (NIH ODS: chromium fact sheet) (MSK About Herbs: alpha-lipoic acid) (NCCIH: Asian ginseng) |
| Anything during pregnancy or breastfeeding | Not for use: harmful to newborns (NCCIH: goldenseal and berberine) | Cayenne should be avoided too (MSK About Herbs: cayenne) |
Amounts inside the 276 mg blend are not published, so nobody can say how strong any of these effects would be. The full list is on the side effects page.
Diabetes medicines
Can you take berberine with metformin?
Only with your doctor's okay. In one study, goldenseal extract, a herb that contains berberine, lowered metformin levels by about 25 percent (NCCIH: goldenseal and berberine).
Slim Metrix adds a second issue. Its chromium may add to the glucose-lowering effect of insulin or metformin (NIH ODS: chromium fact sheet), and alpha-lipoic acid can add to diabetes medicines too (MSK About Herbs: alpha-lipoic acid).
For many people with diabetes, a low means a reading below 70 mg/dL. Shakiness, hunger, dizziness, confusion and a racing heartbeat are common signs, and the risk is higher with insulin and sulfonylurea pills (NIDDK: low blood glucose).
Never stop or cut a prescribed medicine to make room for a supplement.
Transplant drugs
Is berberine safe with cyclosporine or tacrolimus?
Not without your transplant team's approval. Berberine may raise the levels of both drugs (MSK About Herbs: berberine), and the cayenne in Slim Metrix may raise cyclosporine levels as well (MSK About Herbs: cayenne).
These drugs protect a new organ, and your team tunes them with blood tests. Skip berberine products unless that team says yes.
Pregnancy
Can you take berberine while pregnant or breastfeeding?
No. NCCIH says berberine can be harmful to newborns, so it should not be used in pregnancy, while breastfeeding or in infants (NCCIH: goldenseal and berberine).
MSK adds that it may worsen jaundice in babies (MSK About Herbs: berberine). If you might be pregnant, wait.
Quick check
Should you take a product with berberine? A 7-question check
Answer all seven. A single yes on the medicine questions means talk to your doctor first.
Your next step
What should you ask your pharmacist about berberine?
Ask whether any of your medicines use the CYP enzymes berberine slows. Then ask about the other nine ingredients on the label.
Bring the bottle
Show the Supplement Facts, not an ad. The seller's short list names six ingredients; the label adds four more.
List every medicine
Prescriptions, store-bought drugs and supplements.
Ask about your numbers
If you take diabetes medicine, ask how often to check your blood sugar at the start.
Read more in our berberine profile.
Bottom line
What is the safest way to approach berberine?
Check first, then decide. The interactions are documented; the weight effects are small.
FAQ
Berberine and medicines: your questions
Can I take berberine with metformin?
Ask your doctor first. A berberine-containing herb lowered metformin levels about 25% in one study (NCCIH: goldenseal and berberine), and the chromium in Slim Metrix may add to metformin's glucose-lowering effect (NIH ODS: chromium fact sheet). Never change or stop a prescribed medicine on your own to try a supplement.
Which CYP enzymes does berberine affect?
Berberine lowered CYP2D6, CYP2C9 and CYP3A4 activity in people, according to Memorial Sloan Kettering (MSK About Herbs: berberine). These enzymes clear many common prescription drugs. A pharmacist can check your list in a few minutes and tell you whether any of your medicines depend on them.
Can I take berberine after an organ transplant?
Only if your transplant team approves. Berberine may raise cyclosporine and tacrolimus levels (MSK About Herbs: berberine), and cayenne, also in Slim Metrix, may raise cyclosporine levels (MSK About Herbs: cayenne). Your team adjusts these drugs with blood tests, so a supplement that shifts them can cause real harm.
Does Slim Metrix interact with blood pressure medicine?
It might. Our sources list no berberine interaction with blood pressure drugs, but capsaicin from cayenne may affect blood pressure medicines (MSK About Herbs: cayenne). Cayenne is one of the eight ingredients in the Slim Metrix blend, so ask your pharmacist before you combine them.
Is Slim Metrix safe while breastfeeding?
No. Slim Metrix lists berberine, which can be harmful to newborns and should not be used while breastfeeding (NCCIH: goldenseal and berberine). Cayenne should also be avoided while nursing (MSK About Herbs: cayenne). Wait until you have stopped breastfeeding, and talk with your doctor about safer ways to manage weight.
Does Slim Metrix interact with blood thinners?
It may. Resveratrol may raise bleeding risk with warfarin (MSK About Herbs: resveratrol), Korean ginseng may interfere with clotting (NCCIH: Asian ginseng), and milk thistle may interact with warfarin (MSK About Herbs: milk thistle). All three are in the Slim Metrix blend, so ask the doctor who manages your blood thinner first.
What should I show my pharmacist before taking Slim Metrix?
Show the full Supplement Facts with all ten ingredients, plus a list of every medicine and supplement you take. The seller's short list names only six ingredients, and the four it leaves out include alpha-lipoic acid and ginseng, which may affect blood sugar (MSK About Herbs: alpha-lipoic acid) (NCCIH: Asian ginseng).
Who wrote this
Written and reviewed by
Plain-language pages built from the brand's label graphic, the sales page and linked medical sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a U.S. stocking partner for Slim Metrix, not by the manufacturer. We earn money when you buy through our order links.
Keep reading
More about Slim Metrix
Side effects
Side effects of all ten Slim Metrix ingredients, the medicines to ask about, and who should not take it.
Read moreBerberine
Berberine in Slim Metrix: why one capsule cannot reach a studied dose, and who should skip it.
Read more
Berberine research
What a 2025 review found for berberine, how strong the trials were, and how one Slim Metrix capsule compares.
Read moreU.S. stocking partner for Slim Metrix
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