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Supplement · Grade A

Alpha Lipoic Acid and medications.

Every documented pair, every citation. Below: 9 documented pairs grouped by mechanism.

Alpha Lipoic Acid is in the Distil supplement database, evidence Grade A. The page below lists every medication we have explicitly assessed it against.

Alpha lipoic acid is an antioxidant that works in both fat- and water-based parts of the body and helps recycle vitamins C and E. Its strongest evidence is Grade A for diabetic neuropathy, with Ziegler's work as the anchor, and Grade B for broader antioxidant and metabolic effects including insulin sensitivity. The active form is R-ALA; standard racemic ALA is half inactive S-ALA, so effectively half the dose, and the usual target is 300 to 600mg of R-ALA. On interactions, it needs a 4-hour separation from thyroid medication. It also lowers blood glucose, so stacking it with metformin and berberine creates a triple glucose-lowering effect that warrants watching for hypoglycaemia. It pairs well with vitamins C and E in the antioxidant network. Take it with food to limit stomach upset, and consider a B-complex alongside, since very high doses can deplete thiamine.

Below are the 9 documented pairs we have explicitly assessed for Alpha Lipoic Acid: 9 amber. The pairs cluster around 2 mechanisms: Additive glucose lowering and Reduced 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

Last reviewed 17 June 2026. Each interaction below is assessed against PubMed-indexed evidence.

Additive glucose lowering

Amber Does interact with Empagliflozin?

Alpha lipoic acid may lower blood sugar by improving how your body responds to insulin. Empagliflozin also lowers blood sugar, so the two may add up. The combination is usually manageable because empagliflozin rarely causes low blood sugar on its own, but monitor your glucose when you start alpha lipoic acid or change the dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 31221283 · BNF: Empagliflozin

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Gliclazide?

Alpha lipoic acid can lower blood sugar by improving how your body responds to insulin. Gliclazide already lowers blood sugar, so taking the two together may add up and could push your glucose too low. If you take both, monitor your blood glucose, especially in the first few weeks, and your doctor may need to reduce the gliclazide dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 31221283 · PMID 11951812 · BNF: Gliclazide

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Glimepiride?

Alpha lipoic acid can lower blood sugar by improving how your body responds to insulin. Glimepiride already lowers blood sugar, so the two may add up and could push your glucose too low. If you take both, monitor your blood glucose, especially in the first few weeks, and your doctor may need to reduce the glimepiride dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 31221283 · PMID 11951812 · BNF: Glimepiride

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Insulin aspart?

Alpha lipoic acid may improve how your body responds to insulin, which can lower blood sugar on top of the insulin you inject. This may increase the chance of glucose going too low. If you take alpha lipoic acid with insulin, monitor your blood glucose closely, especially early on, and your doctor may need to reduce your insulin dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 11951812 · PMID 31221283 · BNF: Insulin aspart

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Insulin glargine?

Alpha lipoic acid may improve how your body responds to insulin, which can lower blood sugar on top of the insulin you inject. This may increase the chance of glucose going too low. If you take alpha lipoic acid with insulin, monitor your blood glucose closely, especially early on, and your doctor may need to reduce your insulin dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 11951812 · PMID 31221283 · BNF: Insulin glargine

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Metformin?

Alpha lipoic acid may improve how your body responds to insulin and lower blood sugar. Metformin also lowers blood sugar, so the two may add up. The combination is generally manageable because metformin on its own rarely causes low blood sugar, but monitor your glucose when you start alpha lipoic acid or change the dose, and your doctor may adjust the metformin if needed.

Evidence: Supported by human study data.

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Pioglitazone hydrochloride?

Alpha lipoic acid may lower blood sugar by improving how your body responds to insulin. Pioglitazone works the same way, by improving insulin sensitivity, so the two may add up. The combination is usually manageable, but monitor your glucose when you start alpha lipoic acid or change the dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 31221283 · BNF: Pioglitazone

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Does interact with Sitagliptin?

Alpha lipoic acid may lower blood sugar by improving how your body responds to insulin. Sitagliptin also lowers blood sugar, so the two may add up. The combination is usually manageable because sitagliptin rarely causes low blood sugar on its own, but monitor your glucose when you start alpha lipoic acid or change the dose.

Evidence: Supported by human study data.

PMID 29990473 · PMID 31221283 · BNF: Sitagliptin

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Reduced thyroid-hormone effect

Amber Does interact with Levothyroxine?

Alpha lipoic acid may slow the body's conversion of thyroid hormone into its active form, so in theory it could blunt some of the benefit you get from levothyroxine and let a few underactive-thyroid symptoms creep back. This is based on animal studies rather than people, and the evidence is not all one way, so it is not a reason to avoid the combination. If you take levothyroxine, tell the clinician who manages your thyroid before starting alpha lipoic acid and ask for a thyroid blood test (TSH) a few weeks later so your dose can be reviewed if needed.

Evidence: Based on an established mechanism, with no direct study of this exact combination yet.

PMID 1815532 · PMID 26947333 · PMID 36404819 · BNF: Levothyroxine

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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