Ashwagandha and medications.
Ashwagandha is in the Distil supplement database, evidence Grade A. The page below lists every medication we have explicitly assessed it against.
Ashwagandha is an adaptogenic herb best evidenced for lowering cortisol and improving stress resilience, where the trials are Grade A; its effects on testosterone, sleep, and thyroid sit at Grade B, meaning promising but less settled. It works on the HPA axis, the body's stress response system. Only the standardised KSM-66 and Sensoril extracts have been trialled, at 300 to 600mg and 125 to 250mg respectively; raw powder is not equivalent. One trial found KSM-66 normalised thyroid markers in subclinical hypothyroidism, but the same activity means caution in hyperthyroidism. The interactions need care. It can alter thyroid hormone levels, so flag it if you take thyroid medication. It adds to the sedation of benzodiazepines, and may interfere with immunosuppressants, so avoid it after a transplant or with autoimmune disease without prescriber input. Never start it at the same time as Rhodiola; stagger by at least four weeks. Avoid in pregnancy. If used beyond eight weeks, taper over a week or two rather than stopping abruptly.
Below are the 15 documented pairs we have explicitly assessed for Ashwagandha: 15 amber. The pairs cluster around 6 mechanisms: Additive CNS sedation, Additive CNS depression, Immune-stimulant vs immunosuppressant (precautionary), Additive serotonergic activity, Calming effect vs stimulant (opposing), and Additive thyroid-hormone effect. 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
Additive CNS sedation
Ashwagandha can have a calming, mildly sedating effect and improves sleep for some people, and clonidine commonly causes drowsiness and tiredness. Taken together they may add to the sedation. Use with care, particularly around driving, and especially in the first weeks.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can have a calming, mildly sedating effect and improves sleep for some people, and guanfacine commonly causes drowsiness and tiredness. Taken together they may add to the sedation. Use with care, particularly around driving, and especially in the first weeks.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive CNS depression
Ashwagandha can have a mild sedating effect on top of its main anti-stress action. Combined with alprazolam, the sedation can stack. Use with care around driving or heavy machinery.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can have a mild sedating effect on top of its main anti-stress action. Combined with diazepam, the sedation can stack. Use with care around driving or heavy machinery.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can have a mild sedating effect on top of its main anti-stress action. Combined with lorazepam, the sedation can stack.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can have a mild sedating effect on top of its main anti-stress action. Combined with temazepam, the nocturnal sedation can stack.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Immune-stimulant vs immunosuppressant (precautionary)
Ciclosporin works by calming the immune system down, which is what stops your body rejecting a transplant or quietens an autoimmune condition. Ashwagandha has been reported to do the opposite and gently stimulate the immune system. There is no proof the two clash in people, but because the stakes with a transplant or autoimmune disease are high, it is safer not to start ashwagandha while you take ciclosporin without first talking to your transplant or specialist team.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Tacrolimus works by calming the immune system down, which is what stops your body rejecting a transplant or quietens an autoimmune condition. Ashwagandha has been reported to do the opposite and gently stimulate the immune system. There is no proof the two clash in people, but because the stakes with a transplant or autoimmune disease are high, it is safer not to start ashwagandha while you take tacrolimus without first talking to your transplant or specialist team.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive serotonergic activity
Ashwagandha has mild effects on serotonin pathways that overlap with citalopram. Most people tolerate the combination but watch for restlessness, jaw tension, or sleep disruption.
Ashwagandha has mild effects on serotonin pathways that overlap with sertraline. Most people tolerate the combination but watch for restlessness, jaw tension, or sleep disruption.
Calming effect vs stimulant (opposing)
Ashwagandha is calming and mildly sedating, while dexamfetamine is a stimulant, so the two pull in opposite directions. In theory ashwagandha could take the edge off how well your medication works, or change how settled or wired you feel. No studies have tested the two together in people, so this is a watch-and-see caution rather than a hard rule. If you take both, keep an eye on whether your focus, sleep, or heart rate feel different, and do not change your stimulant dose without your prescriber knowing.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha is calming and mildly sedating, while lisdexamfetamine is a stimulant, so the two pull in opposite directions. In theory ashwagandha could take the edge off how well your medication works, or change how settled or wired you feel. No studies have tested the two together in people, so this is a watch-and-see caution rather than a hard rule. If you take both, keep an eye on whether your focus, sleep, or heart rate feel different, and do not change your stimulant dose without your prescriber knowing.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha is calming and mildly sedating, while methylphenidate is a stimulant, so the two pull in opposite directions. In theory ashwagandha could take the edge off how well your medication works, or change how settled or wired you feel. No studies have tested the two together in people, so this is a watch-and-see caution rather than a hard rule. If you take both, keep an eye on whether your focus, sleep, or heart rate feel different, and do not change your stimulant dose without your GP knowing.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive thyroid-hormone effect
Carbimazole is given to bring an overactive thyroid down. Ashwagandha tends to push thyroid hormone the other way, up, so it can work against your treatment. It is best not to add ashwagandha while you are being treated for an overactive thyroid. If you already take both, tell your GP and have your thyroid bloods checked.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Ashwagandha can nudge your own thyroid hormone levels up. On top of levothyroxine, that can tip you into having a bit too much thyroid hormone, with symptoms like a racing heart, feeling wired, or losing weight. If you take both, it is worth asking your GP to check your thyroid blood tests, as your levothyroxine dose may need lowering.
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.
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.
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- the evidence-backed compounds worth adding, and the ones worth dropping
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