Supplements and Simvastatin.
Simvastatin, sold under the brand name Zocor, is a statin: it lowers LDL cholesterol by inhibiting HMG-CoA reductase. Statins are the most-prescribed class in the UK.
Below are the 5 documented pairs we have explicitly assessed against Simvastatin in the Distil database: 1 red, 3 amber, and 1 green. The pairs cluster around 3 mechanisms: Additive muscle toxicity, Additive lipid lowering, and CYP3A4 inhibition. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Additive muscle toxicity
High-dose niacin combined with simvastatin raises the risk of severe muscle breakdown (rhabdomyolysis). The FDA has a class warning on this combination. Do not combine.
Additive lipid lowering
Berberine lowers LDL cholesterol on its own. Combined with simvastatin the effect is additive. If you take both, ask for a lipid panel sooner than usual after starting so your GP can confirm you are not pushing lipids lower than intended.
CYP3A4 inhibition
Curcumin may slow how the body clears simvastatin via CYP3A4. Simvastatin is more sensitive to CYP3A4 inhibition than atorvastatin, so the effect on muscle and liver side-effect risk may be larger. We treat this as a watch-and-tell-your-GP pair.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Quercetin may slow how the body clears simvastatin via CYP3A4. Because simvastatin is more sensitive to CYP3A4 inhibition than atorvastatin, the effect may be larger. Watch for muscle pain and tell your GP if you take both.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Other
Statins do reduce plasma CoQ10 levels, but the best-quality randomised trials show that taking CoQ10 alongside a statin does not reliably reduce muscle pain or improve other statin side effects. We treat the pair as safe to combine. If you find it helps you personally that is fine, but the evidence for routine use is weak.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
For adults over 18.
This tool gives evidence-graded information, not medical advice. Always discuss changes with your GP, pharmacist, or specialist before making them, especially if you take any medication, are pregnant, breastfeeding, or have a serious health condition.
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 methodologySomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us and we'll add it in the next quarterly update.