Guide
Memory Supplements and Medicines: Interactions to Check Before You Mix
Memory supplements and medicines can interact. St. John's wort changes how many drugs work, ginkgo may raise bleeding risk with blood thinners, and carnitine matters in seizure disorders. Bring every pill and the supplement bottle to your pharmacist before you start.
Prepared by the MemoPryl label deskUpdated
Background01
Can memory supplements interact with medicines?
Yes, memory supplements can interact with medicines, because herbs and amino acids act on the body, too. "Natural" on a label does not mean harmless (NCCIH, supplements wisely).
The NIH advises telling every provider about every supplement you take, and keeping a written record of the name, dose, how often and why (NIH ODS, supplements basics). It also says to check with a provider before combining a supplement with prescribed medicine.
The ingredients below are the ones named for MemoPryl, whose amounts are not published. Other products with a different formula may carry other cautions, so read the bottle you hold.
Do not stop, skip or change a prescription because of something you read. Any change belongs to the person who prescribed it.
Quick reference02
Which medicines do ginkgo, St. John's wort and carnitine affect?
Ginkgo, St. John's wort and carnitine each have their own medicine cautions, and St. John's wort has the longest list. The table gathers what the NIH and other sources we read say.
It is not complete. A pharmacist can check your exact medicines against an exact product, which a table cannot do.
| Ingredient | Medicines or situations flagged | Source |
|---|---|---|
| Ginkgo biloba leaf | Blood thinners such as warfarin (higher major-bleeding risk); some HIV medicine; seizure history; surgery; pregnancy | (NCCIH, herb-drug interactions) (EMA/HMPC, Ginkgo monograph) (MSK, Ginkgo) |
| St. John's wort | Birth control pills, warfarin, cyclosporine, some HIV drugs, digoxin, oxycodone, some cancer drugs, certain antidepressants | (NCCIH, St. John's wort in depth) (NCCIH, herb-drug interactions) |
| N-acetyl L-carnitine | Seizure disorders; some seizure drugs lower carnitine levels | (NIH ODS, Carnitine) |
| Bacopa | Thyroid medicine, anticholinergic drugs, medicines processed by liver enzymes | (Merck Manual, Bacopa) |
| Phosphatidylserine | Blood thinners and blood pressure medicine, as it may raise bleeding risk or lower blood pressure | (ADDF, phosphatidylserine) |
| L-glutamine | No medicine interaction found in the sources we read; stomach upset at high amounts | (Ogden 2020, L-glutamine tolerance) |
"No interaction found" means we did not find one, not that none exists.
Bleeding risk03
Is ginkgo safe with blood thinners?
Ginkgo is not a good match with blood thinners unless your prescriber agrees, because it may raise bleeding risk. Taking it with warfarin is linked to a higher chance of major bleeding than warfarin alone (NCCIH, herb-drug interactions).
Memorial Sloan Kettering also warns about spontaneous bleeding case reports (MSK, Ginkgo). The European herbal monograph says people who bleed easily, or take anticoagulant or antiplatelet drugs, should use it only after a doctor's advice, and that it should be stopped 3 to 4 days before surgery (EMA/HMPC, Ginkgo monograph).
Daily aspirin counts as a blood thinner for this purpose. Tell the surgeon or dentist about every supplement before a procedure.
Before you start
Ask the prescriber of your blood thinner, and show them the bottle.
Watch for
Unusual bruising, nosebleeds that do not stop, black stools or blood in urine. Contact your doctor promptly.
Before surgery
Tell the surgical team. Do not time a stop date yourself; follow their instructions.
The longest list04
Why does St. John's wort interact with so many medicines?
St. John's wort interacts with many medicines because it speeds up the enzymes and transporters the body uses to clear them. The NIH calls its overall risk of drug interaction high (NCCIH, herb-drug interactions).
The result can be a medicine that works less well. The NIH lists birth control pills, warfarin, cyclosporine, some HIV drugs, digoxin, oxycodone and some cancer drugs (NCCIH, St. John's wort in depth). For birth control, that raises a question about unplanned pregnancy, so ask a pharmacist.
With some antidepressants, the effects can add up and raise serotonin to a dangerous level. Symptoms include agitation, diarrhea, a fast heartbeat, high blood pressure, hallucinations and fever (NCCIH, St. John's wort in depth). It can also cause sensitivity to sunlight.
What research studied it for
- Mild to moderate depression, in trials of specific extracts (NCCIH, St. John's wort) (Cochrane, St. John's wort)
What it was not studied for here
- Memory. The sources we read describe no memory research for it.
- Replacing standard depression care, which the NIH says it should not do (NCCIH, St. John's wort in depth)
Check yours05
How do you check a supplement against your medicines?
To check a supplement against your medicines, bring both to a pharmacist or prescriber before the first dose. Five quick questions show whether you are in a group that needs that talk most.
The answers are a prompt, not medical advice. If any is a yes, make the call before you begin, and if the answer to the last is yes, get care now.
Lay everything out
Gather every prescription, over-the-counter product and supplement, with the bottles.
Match the names
Compare each ingredient name on your supplement bottle with the table above. If a name differs from what you expected, ask the seller before you take it.
Ask by name
Show the pharmacist the bottle and ask about each ingredient against each of your medicines.
Write a start date
If you go ahead, note the date and any new symptoms. Stop and call your provider if side effects occur (NCCIH, supplements wisely).
If something goes wrong06
What should you do if you think a supplement caused a reaction?
If you think a supplement caused a serious reaction, stop taking it and get medical help right away. The FDA gives this advice (FDA, report a problem).
Consumers can then file a voluntary report through the FDA's Safety Reporting Portal, choosing the private citizen option (FDA, report a problem). Keep the bottle and your order email, because they identify the product.
For the named ingredients in more detail, see the side effects guide and the who it is for page. For how research compares them, read the memory supplements compared guide.
FAQ07
MemoPryl questions people ask
Can I take ginkgo while on warfarin?
Only if the prescriber of your warfarin agrees. Ginkgo with warfarin has been linked to a higher risk of major bleeding than warfarin alone (NCCIH, herb-drug interactions). Ask before you start, and never stop warfarin on your own.
Does St. John's wort make birth control less effective?
It may. The NIH lists birth control pills among the medicines St. John's wort can weaken (NCCIH, St. John's wort in depth). If you use hormonal birth control, ask a pharmacist before taking it, and do not rely on guesswork.
Can St. John's wort be taken with antidepressants?
Combining it with certain antidepressants can raise serotonin to a dangerous level (NCCIH, St. John's wort in depth). Do not combine them without your prescriber. Also keep taking your antidepressant as directed rather than swapping it.
Does carnitine matter for people with seizures?
Yes. About 3 g a day can cause seizures in people with seizure disorders, and some seizure drugs lower blood carnitine (NIH ODS, Carnitine). Anyone with epilepsy should ask their neurologist first.
When should I stop ginkgo before surgery?
The European herbal monograph says to stop 3 to 4 days before surgery (EMA/HMPC, Ginkgo monograph). Tell your surgeon about it anyway, since they decide the timing for you.
Which pharmacist question matters most?
Ask: "Does any ingredient on this bottle affect any medicine I take?" Hand over the bottle and your full medicine list. Naming each ingredient lets the pharmacist check them one by one.
Do supplements need FDA approval before they are sold?
No. The FDA cannot approve supplements for safety and effectiveness before sale (FDA, using supplements). That is one reason to check interactions yourself with a pharmacist before you begin.
Who wrote this08
Written and reviewed by
Pages built from the label, the official site, the sales page and linked NIH, FDA, FTC and peer-reviewed sources.
Last updated . Find our editorial standards and how we check reviews. This website is run by a U.S. order-link partner, not by the maker of MemoPryl. This site earns a commission when you buy through our order links.
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