Supplements and Efavirenz.
Efavirenz, sold under the brand name Sustiva, is a non-nucleoside reverse transcriptase inhibitor (NNRTI): it binds reverse transcriptase directly at an allosteric site. NNRTIs are CYP3A substrates.
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI). The class binds HIV reverse transcriptase directly and forms a backbone of combination antiretroviral therapy. Efavirenz, the most established agent, is itself a CYP3A4 inducer and a CYP2B6 substrate, which is why its own drug interactions run deep. The supplement rules follow the same logic as the protease inhibitor page. Steady antiretroviral levels are what hold the virus suppressed, so anything that shifts them risks toxicity or, more dangerously, treatment failure and resistance. St John's Wort sits on the induction side and is the textbook exclusion. Supplements that inhibit CYP3A4, including curcumin, quercetin, resveratrol, schisandra, berberine, boswellia and bergamot, can raise levels instead. Bergamot is grapefruit-family citrus, the class whose interaction with these drugs is best documented in people. Boswellia is the least settled of them: laboratory work on the gum resin shows CYP3A4 inhibition, one study reports the opposite effect, and a literature search found no study of the combination in people, which is reason enough to keep it out of a regimen that depends on a steady level. Immune-active herbs (echinacea, andrographis, elderberry, cordyceps, astragalus) are excluded as a precaution on antiretroviral therapy regardless of CD4 count. As with all antiretroviral therapy, the HIV team signs off any new supplement rather than community pharmacy.
Below are the 12 documented pairs we have explicitly assessed against Efavirenz in the Distil database: 6 red, 5 amber, and 1 green. The pairs cluster around 3 mechanisms: CYP induction, CYP-mediated metabolism, and Immunosuppression caution. 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
Last reviewed 28 August 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
CYP induction
Red Does St John's Wort interact with ?
St John's Wort speeds up how the body clears the HIV medicine efavirenz, which can drop the drug level too low to control the virus and let HIV become resistant. This is a serious interaction and the two should not be combined. If you take efavirenz, do not start St John's Wort, and if you already take both, tell your HIV team before changing anything.
Evidence: Supported by human study data.
Amber Does Ginkgo Biloba interact with ?
Ginkgo may lower the level of the HIV medicine efavirenz in the blood, which could let the virus rebound. This has been reported in patients who were stable for years and then lost virus control after starting ginkgo. If you take efavirenz, it is best to avoid ginkgo, or only use it with your HIV team's knowledge and viral-load monitoring.
Evidence: Limited human data, from small studies or case reports, alongside a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
CYP-mediated metabolism
Red Does Andrographis interact with ?
Andrographis may shift efavirenz levels, and efavirenz has a narrow band where it works well without causing side effects, so we treat this as a do-not-combine pair outside your HIV team's supervision. The main route your body uses to clear efavirenz has been tested against andrographis in the laboratory and did not appear to be affected, but the backup route is one andrographis does slow, and efavirenz is given without the booster drug that would otherwise mask that. There is a second reason to be careful: rashes are common in the first weeks of efavirenz and are also among the commonest side effects of andrographis, so taking both makes it harder for your team to tell which one is causing a rash and whether it is the dangerous kind.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Boswellia interact with ?
Boswellia may change how quickly the body clears efavirenz, and the laboratory evidence points both ways at once, so we cannot say whether your levels would go up or down. Either direction matters, and efavirenz is less forgiving than most: a level that drifts too low may let the virus rebound and become resistant to this whole family of HIV medicines, while a level that drifts too high tends to bring on dizziness, vivid dreams and mood changes. We treat this as a do-not-combine pair, and if you are already taking both, tell your HIV team before you change anything.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Curcumin interact with ?
Curcumin (from turmeric) may shift efavirenz levels in either direction, and efavirenz has a narrow band where it works well without causing side effects, so we treat this as a do-not-combine pair outside your HIV team's supervision. Too little efavirenz may let the virus become resistant, and too much tends to worsen the dizziness, vivid dreams and low mood that this medicine can cause. Cooking amounts of turmeric in food are not the concern; concentrated curcumin supplements are, and no study has tested this combination in people.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Resveratrol interact with ?
Resveratrol supplements may shift efavirenz levels, and we cannot say reliably in which direction, so we treat this as a do-not-combine pair outside your HIV team's supervision. Too little efavirenz may let the virus become resistant to this whole family of HIV medicines, and too much tends to worsen the dizziness, vivid dreams and low mood it can cause. The small amounts in red wine and grapes are not the concern; concentrated supplements are, and no study has tested this combination in people.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does Schisandra interact with ?
Schisandra may change the amount of efavirenz in your blood, and it is not clear in which direction, because schisandra both slows and speeds up the liver enzymes that handle medicines. Either direction is a problem, since too little efavirenz can let HIV become resistant and too much can worsen the dizziness, vivid dreams and mood effects efavirenz can cause. Do not combine schisandra with efavirenz unless your HIV team has agreed it, and note this advice comes from how schisandra behaves with other medicines rather than from any study of schisandra with efavirenz, because none has been done.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Berberine interact with ?
If you take efavirenz, tell your HIV team before starting berberine. No study has tested this combination in people, so the caution rests on how berberine behaves with other medicines rather than on any measured effect on efavirenz, and the main enzyme that clears efavirenz has never been tested with berberine in a person. What berberine is known to do in people is slow certain liver enzymes rather than speed them up, so if anything it may nudge efavirenz levels up rather than down; this is not the pattern seen with St John's Wort or ginkgo, which have been linked to efavirenz levels falling and the virus rebounding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Bergamot Extract (BPF / Bergavit40) interact with ?
Bergamot is grapefruit-family citrus, and while it may have some effect on efavirenz levels the overlap is small, so the sensible step is to tell your HIV team before starting it rather than to avoid it outright. Efavirenz is cleared mainly by a liver enzyme that bergamot is not known to affect, and efavirenz speeds up the one enzyme bergamot does act on, so any effect tends to be limited. No study has tested bergamot with efavirenz, or with any HIV medicine, in people, so this is a precaution based on mechanism rather than a measured effect.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Quercetin interact with ?
Quercetin supplements may shift efavirenz levels, and of the HIV medicines we assess this is the one we know least about, so if you take efavirenz do not start quercetin without telling your HIV team first. Efavirenz is cleared mainly by a liver enzyme that has never been tested with quercetin in any study, and it is taken without a booster drug, which leaves it more exposed than the protease inhibitors. A fall in efavirenz level can let HIV become resistant, so viral load is what your team would keep an eye on.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Immunosuppression caution
Amber Does Cordyceps interact with ?
Cordyceps is sold as an immune supplement, but the human trials behind it were run in transplant patients where it acted alongside immune-suppressing medicines rather than against them, so what it does to an immune system already being managed for HIV has never been studied and it belongs with your HIV team before you start it. Efavirenz is handled by a different liver pathway from the protease inhibitors and is taken without a booster, and our curated interaction database records no evidence that cordyceps touches either that pathway or the one the protease inhibitors use. The reason for care here is your immune monitoring rather than your drug levels.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Other
Green Does Elderberry interact with ?
Elderberry is often described as risky for people living with HIV because it stimulates the immune system, and our curated interaction database records no interaction between elderberry and efavirenz: efavirenz works by blocking an enzyme the virus needs rather than by damping your immune system, so there is nothing here for elderberry to push against. Efavirenz is broken down mainly by a different liver enzyme from the other HIV medicines, and we have not identified a study of elderberry against that particular enzyme, so this one rests on there being no signal anywhere rather than on a direct test. We treat this pair as safe to combine, and because efavirenz has a fairly narrow band where it works well without causing vivid dreams or low mood, it is worth telling your HIV team about any supplement you start.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
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.
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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 methodologyA 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.
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