NAC and medications.
NAC is in the Distil supplement database, evidence Grade A. The page below lists every medication we have explicitly assessed it against.
NAC, or N-acetyl cysteine, is a precursor to glutathione, the body's main internal antioxidant. By topping up glutathione it may support lung health and reduce oxidative stress, with Grade A evidence in that antioxidant and respiratory role. The evidence is Grade B for mood and for repetitive behaviours in autism, where Dean's RCT is the anchor, and Grade B for the liver, where an RCT in NASH showed improvements in liver tissue and enzymes. The usual dose is 600mg twice daily. The interactions worth knowing: NAC has an effect on clotting through von Willebrand factor, so as a precaution it is worth pausing a couple of weeks before any planned surgery, and worth a mention to your GP if you take a blood thinner. That effect has only been shown at doses far higher than a supplement provides, with no clear human bleeding data at supplement doses, so treat it as a conservative flag rather than an established risk. It also potentiates the blood-pressure-lowering of nitroglycerin, which is a pairing to avoid. On the positive side, glycine and NAC together as GlyNAC tend to outperform either alone for glutathione restoration. Take it with food to limit stomach upset, and expect a harmless rotten-egg smell in urine at high doses.
Below are the 2 documented pairs we have explicitly assessed for NAC: 2 amber. The pairs cluster around 1 mechanism: Additive vasodilation. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Last reviewed 14 June 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.
Additive vasodilation
Amber Does interact with Glyceryl trinitrate?
Taking NAC with glyceryl trinitrate (GTN) can make GTN act more strongly, which may mean a more pronounced headache and a larger drop in blood pressure than GTN alone, because NAC is a sulfur-rich compound and GTN needs sulfur groups in the body to work. If you use a GTN spray or patch and take NAC, watch for dizziness, faintness on standing, or worse headaches, and tell your GP or pharmacist so they can review the timing or doses.
Evidence: Supported by human study data.
Amber Does interact with Isosorbide mononitrate?
Taking NAC with isosorbide mononitrate may make the nitrate act more strongly, which can mean a more pronounced headache and a larger drop in blood pressure than the nitrate alone, because NAC is a sulfur-rich compound and nitrate medicines rely on sulfur groups in the body to work. If you take isosorbide mononitrate and want to use NAC, watch for dizziness, faintness on standing, or worse headaches, and tell your GP or pharmacist so they can review the timing or doses.
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. Use the checker below to surface any medication, 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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