Drug & supplement interaction

Sweet Violet + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated June 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Sweet Violet and Levothyroxine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Levothyroxine states a food rule worth keeping to.

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Interaction report

Sweet Violet and Levothyroxine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Levothyroxine and Sweet Violet in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Sweet Violet at all — not against Levothyroxine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Sweet Violet safety at a glance

Sweet Violet overall Use caution Generally regarded as gentle in small culinary or tea amounts, but human safety data are limited.

Pregnancy Avoid Not enough safety information is available, so it is best avoided during pregnancy.

Breastfeeding Avoid There is not enough information to know if it is safe while breastfeeding, so avoid it.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine and Sweet Violet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

What to actually watch for

What Levothyroxine’s Own FDA Label Lists

This is not an interaction — none of it involves Sweet Violet. These are the most notable effects listed in the ADVERSE REACTIONS section of Levothyroxine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 10 of them are worth acting on rather than waiting out — marked below.

A change in thyroid levels Worth acting on
Bone thinning Worth acting on
Muscle weakness Worth acting on
A heart attack Worth acting on
Heart failure Worth acting on
Wheezing Worth acting on
Seizures Worth acting on
Chest pain Worth acting on
Shortness of breath Worth acting on
A severe allergic reaction Worth acting on

Showing the 10 most notable of 32 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed › Sweet Violet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Sweet Violet side to compare — that is a limit of the record, not a statement that Sweet Violet has no side effects.

How to take them

Some Levothyroxine Products Have a Food Rule — Sweet Violet Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Sweet Violet included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Levothyroxine on its own and move Sweet Violet to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Levothyroxine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Overlapping uses

What Levothyroxine Is Prescribed For, and What Sweet Violet Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Levothyroxine is a prescription medicine with approved uses on its FDA label. Sweet Violet is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Levothyroxine is prescribed for: Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain. It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

Sweet Violet has been studied for:

Depression studied, not established Sweet Violet has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows
Sweet Violet for depression
A small study in patients aged 16 to 50 years with mild to moderate depression and insomnia who are taking sertraline shows that taking an extract of sweet violet aerial parts syrup every 12 hours for 4 weeks improves Pittsburgh Sleep Quality Index (PSQI) scores by 10 points, compared with 3 points in those receiving placebo.
1 source cited

106575. Shayesteh M, Vaez-Mahdavi MR, Shams J, et al. Effects of Viola odorata as an Add-On Therapy on Insomnia in Patients with Obsession or Depression: A Pilot Randomized Double-Blind Placebo-Controlled Trial. J Altern Complement Med 2020;26(5):398-408.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Levothyroxine on your own; if you are taking Sweet Violet for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Sweet Violet or Levothyroxine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Sweet Violet or Levothyroxine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Levothyroxine

This page covers Sweet Violet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).

By severity: 2 major · 39 moderate · 9 minor.

From our pharmacist’s overview on the Levothyroxine page

“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine interaction page

One more smart check

Taking Sweet Violet as Part of a Dietary Supplement Product? Check It for Interactions

We hold 14 real supplement products containing Sweet Violet, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sweet Violet. Even though Sweet Violet itself has no known interaction with Levothyroxine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Sweet Violet and Levothyroxine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Sweet Violet

Steady interest

#1,420 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Levothyroxine

Top 10

#2 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Sweet Violet reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Sweet Violet and Levothyroxine records this page draws on were last updated June 22, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Sweet Violet

What is Sweet Violet?

Cough and sore throat
Bronchitis and chest congestion
Trouble sleeping
Skin irritation
Mild constipation
Headache

Sweet Violet is a traditional herb used mainly as a soothing remedy for coughs, sore throats, and minor respiratory complaints. Modern scientific evidence supporting these uses is very limited, so it should not replace proven treatments. It is generally considered gentle in food-like amounts, but talk with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or giving it to a child.

Viola odorata · Violaceae · Flowers, leaves, and roots; sometimes the whole plant · Tea (infusion), syrup, dried herb, tincture, and topical preparations

An interaction check asks whether these two react with each other — it does not ask whether Sweet Violet is a good idea for someone in your situation. Here is what our Sweet Violet record says about it on its own.

Sweet Violet: dosing

There is no standardized or officially established dose for Sweet Violet. Traditional use most often involves a tea made from the dried flowers or leaves, or a syrup for cough, but exact amounts vary widely between products and recipes.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

From our Sweet Violet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Sweet Violet monograph & all interactions

Medication

About Levothyroxine

What Is Levothyroxine Used For?

Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet

Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.

It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

See full Levothyroxine drug information

Keep checking

Other Drugs & Sweet Violet

Browse every other medication we’ve checked against Sweet Violet — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

0Moderate

0Minor

2,829No known interaction

2,829 No interaction

No interaction 2,829 drugs checked — show the list

We also checked Sweet Violet against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Sweet Violet list.

See the full Sweet Violet interactions page

See every supplement checked against Levothyroxine, ranked by severity

Evidence & sources

Sweet Violet References

The 8 references that drive our Sweet Violet monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Beiraghdar F, Einollahi B, Ghadyani A, et al. A two-week, double-blind, placebo-controlled trial of Viola odorata, Echium amoenum and Physalis alkekengi mixture in symptomatic benign prostate hyperplasia (BPH) men. Pharm Biol 2017;55(1):1800-5.
Qasemzadeh MJ, Sharifi H, Hamedanian M, et al. The effect of Viola odorata flower syrup on the cough of children with asthma: a double-blind, randomized controlled trial. J Evid Based Complementary Altern Med 2015;20(4):287-91. doi: 10.1177/21565872155848 PubMed
Feyzabadi Z, Rezaeitalab F, Badiee S, et al. Efficacy of Violet oil, a traditional Iranian formula, in patients with chronic insomnia: A randomized, double-blind, placebo-controlled study. J Ethnopharmacol 2018;214:22-8. doi: 10.1016/j.jep.2017.11.036. PubMed
Shayesteh M, Vaez-Mahdavi MR, Shams J, et al. Effects of Viola odorata as an Add-On Therapy on Insomnia in Patients with Obsession or Depression: A Pilot Randomized Double-Blind Placebo-Controlled Trial. J Altern Complement Med 2020;26(5):398-408.
Taherzadeh Z, Khaluyan H, Iranshahy M, Rezaeitalab F, Eshaghi Ghalibaf MH, Javadi B. Evaluation of sedative effects of an intranasal dosage form containing saffron, lettuce seeds and sweet violet in primary chronic insomnia: A randomized, double-dummy, do
Tafazoli V, Shahriari M, Heydari M, Nikbakht HA, Zarshenaas MM, Nimrouzi M. The Effect of Viola Odorata L. Oil for Fever in Children: A Randomized Triple-blinded Placebo-controlled Clinical Trial. Curr Drug Discov Technol 2020;17(5):696-703. PubMed
Yazdi N, Kardooni M, Namjuyan F, Vardanjani HM, Tafazoli V, Jaladat AM. Efficacy of Sweet Violet (Viola odorata) flower oil on the symptoms of adults with allergic rhinitis: A double-blind randomized placebo-controlled clinical trial. Complement Ther Med PubMed
Saffar Shahroodi A, Nejabat M, Nimrouzi M, Aghaei H, Salehi A, Rezaei Mokarram A. Effects of intranasal administration of violet oil in dry eye disease. Clin Exp Optom 2019;102(6):576-582. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Sweet Violet and Levothyroxine Together: Common Questions

Is it safe to take Sweet Violet with Levothyroxine?

We do not list a known interaction between Sweet Violet and Levothyroxine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Should I take Sweet Violet and Levothyroxine at the same time of day?

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Levothyroxine on its own and move Sweet Violet to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.

Are Sweet Violet and Levothyroxine used for the same thing?

They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Sweet Violet in each. That is a conversation for your prescriber, especially if Levothyroxine is being adjusted to a target.

Does Levothyroxine interact with any supplements?

Yes. Levothyroxine has documented interactions with 50 supplements in our database — Sweet Violet is not one of them. The Levothyroxine interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Sweet Violet monograph Uses, safety profile, and every drug interaction in one place Levothyroxine drug information The full plain-English guide to this medication Levothyroxine supplement interactions Every supplement checked against Levothyroxine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 8 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and Sweet Violet?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.