Supplements and Lithium carbonate.
Lithium carbonate, sold under the brand names Priadel, Camcolit, is a mood stabiliser with a narrow therapeutic window requiring blood-level monitoring.
Lithium is a mood stabiliser. UK psychiatry prescribes it mostly for bipolar disorder maintenance and as augmentation in treatment-resistant depression. The therapeutic window is narrower than almost any other psychiatric medicine. Trough plasma levels are checked regularly because the gap between therapeutic and toxic concentrations sits at roughly 0.4 to 1.2 mmol/L. Levels are sensitive to hydration, sodium intake, and renal function. Three points matter for supplements. First, anything that affects renal sodium handling shifts lithium clearance. Sodium-restricted diets raise lithium levels. High sodium intake lowers them. Second, NSAIDs (ibuprofen, naproxen, diclofenac) reduce lithium clearance and have caused lithium toxicity in case reports. The BNF flags this. Third, dehydration from any cause (gastroenteritis, sauna use, intense exercise) can push lithium into the toxic range. Lithium taken over years also affects thyroid function and kidney function, both requiring annual monitoring. Any supplement decision should run through the prescribing psychiatrist, not a community pharmacist.
Below are the 5 documented pairs we have explicitly assessed against Lithium carbonate in the Distil database: 5 amber. The pairs cluster around 5 mechanisms: Absorption interference, Additive thyroid suppression, Reduced mood-stabiliser effect, Narrow-therapeutic-index prescriber awareness, and Additive serotonergic activity. 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
Absorption interference
Psyllium may reduce how much lithium you absorb if you take them together, which could lower your lithium level below the range that keeps you well. Take your psyllium at least a few hours apart from your lithium, and keep to your scheduled lithium blood tests so any drop is picked up.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive thyroid suppression
Lithium can affect the thyroid and commonly causes an underactive thyroid or goitre over time. Iodine intake interacts with that effect, so taking an iodine supplement on top of lithium can add to the risk of thyroid problems. If you take lithium, do not start an iodine supplement without discussing it with your GP, and make sure your thyroid is being monitored.
Reduced mood-stabiliser effect
One of the leading explanations for how lithium steadies mood is that it lowers myo-inositol levels in the brain. Taking supplemental myo-inositol could in theory work against this and may reduce how well lithium controls mood, and there is a published report of mania in a person taking inositol. If you take lithium, do not start myo-inositol without discussing it with the doctor who manages your lithium first.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Narrow-therapeutic-index prescriber awareness
Omega-3 fish oil and lithium are often taken together on purpose, because omega-3 has been studied as a mood support added on top of lithium and is generally well tolerated. There is no good evidence that omega-3 changes your lithium blood level. The reason to mention it is that lithium has a narrow safe range, and at higher fish oil doses (around 3 grams a day or more) omega-3 has a mild blood-thinning effect, so it is worth telling the doctor who manages your lithium what dose you take and keeping to your usual lithium blood tests.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive serotonergic activity
Saffron has its own mild antidepressant effect that appears to act on serotonin, and lithium also affects serotonin signalling when used for mood. Taking them together may add up. If you take lithium, tell your GP before adding saffron, as lithium needs careful monitoring.
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.
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 methodologyWant this checked across everything you take?
This page checks the pairs you enter. The personalised Distil report goes further:
- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
- where your current routine may be leaving you short of your goals
- the evidence-backed compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 for the first 25 customers. The interactions check is one section of it, and you can read a real one in full before you buy.
See a real sample reportSomething 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.