Class landing · Antiepileptics

Supplements and antiepileptic drugs.

Phenytoin, carbamazepine, valproate, lamotrigine and the CYP-substrate supplements that disrupt seizure control.

Older antiepileptic drugs (phenytoin, carbamazepine, valproate) are strong inducers or inhibitors of CYP enzymes. Newer ones (lamotrigine, levetiracetam) less so. Supplements that share those CYP substrates can shift blood levels in either direction, with seizure-control implications.

The headline exclusion is St John’s Wort: CYP3A4 induction reduces blood levels of most antiepileptics and can break seizure control. Folate is the other side of the same coin: long-term valproate depletes folate, which is associated with elevated homocysteine and (in pregnancy) neural tube defect risk; supplementation is standard. Vitamin D and calcium are flagged on long-term antiepileptic use for bone health (enzyme-inducing AEDs increase vitamin D clearance).

Loading database stats…

No affiliates. No commission. We earn nothing on what you buy.

For adults over 18. This tool gives evidence-graded information, not medical advice. Always discuss changes with your GP or pharmacist, especially if you take any medication, are pregnant, breastfeeding, or have a serious health condition.

Your supplements

Add every supplement you take. Type a name and click each match to add it, as many as you like.

Your medications

Add all your medications, brand or generic. Type and click each match to add it.

Anything we should know? (optional)

Pick any that apply. We adjust the findings where context changes the answer.

I confirm I am 18 or over. This tool gives evidence-graded information, not medical advice; always discuss changes with your GP or pharmacist.

Add all the supplements and medications you take, then check them together in one go.

Not sure where to start? Try one:

How we decide

How we grade severity, choose what's in scope, and what we exclude.

Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.

Read the full methodology

The full report

A full supplement review, built around you, not a generic stack.

The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.

what your diet already covers, so you are not adding a capsule for something food is already handling
which evidence-graded compounds are worth considering for your goals, and which were considered but left out
what to keep, change or stop from what you already take, plus the order to introduce anything new
how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment

The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.

£49 introductory price for early customers. Standard price £79.

Get my report · £49 See a complete sample report

Something missing?

If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.

Thanks, that's logged. We go through flagged items every week.

Distil's interactions database is reviewed and updated every quarter. We grade evidence transparently and publish our methodology, including every database change, at /about/methodology. This tool is information, not a substitute for clinical judgement. If you take medication and supplements together, your GP or pharmacist can review your full regimen against your medical history. If you want a full personalised stack reasoned against this same database, the Distil report is the next step up.