Drug & supplement interaction

Black Tea + Levothyroxine Sodium

Levothyroxine Sodium brand names: Tirosint-Sol, Thyquidity, Ermez.

No Known Interaction

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

The bottom line No known interaction

We found no known interaction between Black Tea and Levothyroxine Sodium 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 Sodium states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Black Tea and Levothyroxine Sodium

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 Sodium and Black Tea 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.

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.

Black Tea safety at a glance

Black Tea overall Generally safe Moderate amounts are generally safe for most healthy adults, but the caffeine can cause problems in large amounts.

Pregnancy Possibly Safe When used orally in moderate amounts. Due to the caffeine content of black tea, mothers should closely monitor their intake to ensure moderate consumption. Caff... Read the full pregnancy detail

Breastfeeding Possibly Safe When used orally in moderate amounts. Due to the caffeine content of black tea, caffeine intake should be closely monitored. Breast milk concentrations of caffe... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine Sodium and Black Tea? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Levothyroxine Sodium

Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine Sodium is filed under 3 classifications — including thyroid hormone, oral drugs. Black Tea has documented interactions with 46 drug classes — the most serious being ephedrine (major), adenosine (adenocard) (moderate) and anticoagulant/antiplatelet drugs (moderate) — and none of Levothyroxine Sodium’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Black Tea Does Interact With Other Medications

Black Tea has 8 major, 572 moderate, 114 minor known drug interactions in our database — Levothyroxine Sodium isn’t one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 572 Minor 114 No known interaction 2,136 (incl. Levothyroxine Sodium)

Taking anything else?

Check Another of Your Medications Against Black Tea

Covers the 2,830 medications we’ve checked against Black Tea. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Black Tea and Levothyroxine Sodium May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 4 of them are worth acting on rather than waiting out — marked below.

Bone thinning Worth acting on Additional detail
Black Tea
“Some epidemiological research suggests that caffeine, which is found in black tea, may be associated with an increased risk of osteoporosis, but conflicting evidence exists. Caffeine can increase urinary excretion of calcium. Females identified with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass.”

Black Tea · Natural Medicines adverse-effect record, reported in bone loss.
6 sources cited

2669. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. PubMed

10202. Massey LK. Is caffeine a risk factor for bone loss in the elderly? Am J Clin Nutr 2001;74:569-70. PubMed

11317. Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J Nutr 1993;123:1611-4. PubMed

6025. Lloyd T, Johnson-Rollings N, Eggli DF, et al. Bone status among postmenopausal women with different habitual caffeine intakes: a longitudinal investigation. J Am Coll Nutr 2000;19:256-61. PubMed

2723. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed

11839. Dews PB, O'Brien CP, Bergman J. Caffeine: behavioral effects of withdrawal and related issues. Food Chem Toxicol 2002;40:1257-61. PubMed
Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›
Seizures Worth acting on Additional detail
Black Tea
“Orally, caffeine in black tea can cause insomnia, nervousness, headache, anxiety, agitation, jitteriness, restlessness, ringing in the ears, tremors, delirium, and convulsions. Caffeine may also exacerbate sleep disturbances in patients with acquired immunodeficiency syndrome (AIDS).

There is some concern that stopping regular use of caffeine may cause withdrawal symptoms such as headache; tiredness and fatigue;”

Black Tea · Natural Medicines adverse-effect record, reported in anxiety.
6 sources cited

11832. Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html. DOI

11838. Holmgren P, Norden-Pettersson L, Ahlner J. Caffeine fatalities--four case reports. Forensic Sci Int 2004;139:71-3. PubMed

13735. Leson CL, McGuigan MA, Bryson SM. Caffeine overdose in an adolescent male. J Toxicol Clin Toxicol 1988;26:407-15. PubMed

10204. Dreher HM. The effect of caffeine reduction on sleep quality and well-being in persons with HIV. J Psychosom Res 2003;54:191-8.. PubMed

13738. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl) 2004;176:1-29. PubMed

2723. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›
Chest pain Worth acting on Additional detail
Black Tea
“Orally, black tea can cause some cardiovascular-related adverse events. Some of these effects may be due to the caffeine content of black tea. Acute administration of black tea can cause increased blood pressure. However, regular consumption does not seem to increase blood pressure or pulse, even in patients with mild hypertension.”

Black Tea · Natural Medicines adverse-effect record, reported in arrhythmia.
6 sources cited

1451. Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed

1452. Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. PubMed

2722. Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. PubMed

13739. Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA 2005;294:2330-5. PubMed

2729. FDA. Proposed rule: dietary supplements containing ephedrine alkaloids. Available at: www.verity.fda.gov (Accessed 25 January 2000).

11832. Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html. DOI
Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›
A severe allergic reaction Worth acting on Additional detail
Black Tea
“Orally, caffeine in black tea can cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare.”

Black Tea · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).
1 source cited

11315. Infante S, Baeza ML, Calvo M, et al. Anaphylaxis due to caffeine. Allergy 2003;58:681-2. PubMed
Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›
Mood changes or irritability / Tiredness / Headache reported in 8.5% of FDA reports for Levothyroxine Sodium Additional detail

Black Tea

Recorded for Black Tea in the same Natural Medicines adverse-effect record shown under Seizures above.

Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›
A fast or pounding heartbeat Additional detail

Black Tea

Recorded for Black Tea in the same Natural Medicines adverse-effect record shown under Seizures above.

Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›
Anxiety or restlessness / Trouble sleeping Additional detail

Black Tea

Recorded for Black Tea in the same Natural Medicines adverse-effect record shown under Seizures above.

Levothyroxine Sodium

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine Sodium. Read the label on DailyMed ›

Showing the 10 most notable of 12 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Black Tea but not commonly for Levothyroxine Sodium: trouble concentrating, raised blood pressure, dependence or withdrawal symptoms and ringing in the ears.

Effects for Levothyroxine Sodium come from the ADVERSE REACTIONS section of its FDA label; effects for Black Tea come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 312,551 voluntary FDA FAERS reports for Levothyroxine Sodium that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Black Tea in Pregnancy & Breastfeeding

Pregnancy Possibly Safe

When used orally in moderate amounts. Due to the caffeine content of black tea, mothers should closely monitor their intake to ensure moderate consumption. Caffeine crosses the human placenta but is not considered a teratogen. Fetal blood concentrations of caffeine approximate maternal concentrations. The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects. In some studies, consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage. This increased risk may be most likely to occur in females with genotypes that confer a slow rate of caffeine metabolism. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy patients can safely consume doses up to 300 mg daily during pregnancy without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations. Advise keeping caffeine consumption below 300 mg daily. This is similar to the amount of caffeine in about 3 cups of black tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as black tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

Pregnancy Possibly Unsafe

When used orally in large amounts. Caffeine from black tea crosses the placenta, producing fetal blood concentrations similar to maternal levels. Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage. Advise keeping caffeine consumption from all sources below 300 mg daily. This is similar to the amount of caffeine in about 3 cups of black tea. High doses of caffeine throughout pregnancy have resulted in symptoms of caffeine withdrawal in newborn infants. High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight. Preliminary evidence from a population study also suggests that increasing consumption of black tea might increase the risk of spina bifida; however, this finding needs to be verified with additional research. Cohort studies suggest that consuming large amounts of caffeine during pregnancy may reduce the height and weight of the infants born as they grow up. In a cohort of mother/infant pairs with a median maternal plasma caffeine level of 168.5 ng/mL (range 29.5-650.5 ng/mL) during pregnancy, birth weights and lengths were lower in the 4th quartile of caffeine intake compared with the 1st. By age 7, heights and weights were lower by 1.5 cm and 1.1 kg respectively. In another cohort of mother/infant pairs with higher maternal pregnancy plasma caffeine levels, median 625.5 ng/mL (range 86.2 to 1994.7 ng/mL), heights at age 8 were 2.2 cm lower, but there was no difference in weights. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as black tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. More evidence is needed to determine the safety of using black tea during pregnancy. For now, advise avoidance of large quantities of black tea during pregnancy.

Lactation Possibly Safe

When used orally in moderate amounts. Due to the caffeine content of black tea, caffeine intake should be closely monitored. Breast milk concentrations of caffeine are thought to be approximately 50% of maternal serum concentrations. Minimal consumption would likely result in limited exposure to a nursing infant.

Lactation Possibly Unsafe

When used orally in large amounts. Consumption of black tea might cause irritability and increased bowel activity in nursing infants. Black tea might also interfere with iron metabolism and folic acid bioavailability in nursing infants. Large doses or excessive intake of black tea should be avoided during lactation.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Levothyroxine Sodium Products Have a Food Rule — Black Tea Should Not Break It

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

Everything else you take

See Every Supplement That Interacts With Levothyroxine Sodium

This page covers Black Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine Sodium 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).

Open the Levothyroxine Sodium interaction page

One more smart check

Taking Black Tea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 271 real supplement products containing Black Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Tea. Even though Black Tea itself has no known interaction with Levothyroxine Sodium, 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 Black Tea and Levothyroxine Sodium 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 Black Tea

Top 25%

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

29 days ago today

Medication Levothyroxine Sodium

Top 5%

#130 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 Black Tea reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Black Tea and Levothyroxine Sodium records this page draws on were last updated July 11, 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 Black Tea

What is Black Tea?

Mental alertness and energy
Heart health support
Blood pressure and cholesterol
Digestive complaints
Weight management
Antioxidant support

Black tea is a popular caffeinated drink made from the fully oxidized leaves of the Camellia sinensis plant, and it contains caffeine and antioxidant plant compounds. Moderate tea drinking is generally safe for most adults and may modestly support heart health and alertness, but it is not a proven treatment for any disease. If you are pregnant, breastfeeding, sensitive to caffeine, or taking medicines, talk to your pharmacist or doctor.

Camellia sinensis · Theaceae · Leaves and leaf buds (fully oxidized) · Brewed tea, tea bags, loose leaf, instant powder, capsules, and standardized extracts

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

Black Tea: dosing

There is no official standardized dose of black tea as a medicine. Most people drink it as a beverage, a few cups per day. A typical cup contains roughly the caffeine of a smaller cup of coffee, but the exact amount depends on the brand and how long it is steeped.For supplements or extracts, the right amount is not well established. Follow the directions on the product label and do not exceed them. Keep in mind that supplements are not closely regulated, so quality can vary.Health agencies often suggest healthy adults keep total caffeine from all sources to a moderate amount each day.

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

Read the full Black Tea monograph & all interactions

Medication

About Levothyroxine Sodium

Most-Reported Side Effects for Levothyroxine Sodium

From FAERS, the FDA’s public side-effect reporting system (312,551 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 26,585 reports

Nausea 22,605 reports

Headache 19,408 reports

Diarrhea 18,759 reports

Dyspnea 16,717 reports

Keep checking

Other Drugs & Black Tea

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

8Major

572Moderate

114Minor

2,135No known interaction

8 Major 572 Moderate 114 Minor 2,135 No interaction

Major

8 interactions

Moderate

572 interactions

Showing 60 of 572 moderate interactions — see all 572 on the Black Tea page.

Minor

114 interactions

Showing 60 of 114 minor interactions — see all 114 on the Black Tea page.

No interaction 2,135 drugs checked — show the list

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

Showing the 60 most looked-up of 2,135 medications checked with no known interaction — see the full Black Tea list.

See the full Black Tea interactions page

See every supplement checked against Levothyroxine Sodium, ranked by severity

Evidence & sources

Black Tea References

The 150 references that drive our Black Tea 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.

McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
Hertog MGL, Sweetnam PM, Fehily AM, et al. Antioxidant flavonols and ischemic heart disease in a Welsh population of men: the Caerphilly Study. Am J Clin Nutr 1997;65:1489-94. PubMed
Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. PubMed
Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. PubMed
Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. PubMed
Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. PubMed
Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3.
Lasswell WL Jr, Weber SS, Wilkins JM. In vitro interaction of neuroleptics and tricylic antidepressants with coffee, tea, and gallotannic acid. J Pharm Sci 1984;73:1056-8. PubMed
Kulhanek F, Linde OK, Meisenberg G. Precipitation of antipsychotic drugs in interaction with coffee or tea. Lancet 1979;2:1130.
Merhav H, Amitai Y, Palti H, Godfrey S. Tea drinking and microcytic anemia in infants. Am J Clin Nutr 1985;41:1210-3.
Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. PubMed
Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed
Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. PubMed
Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. PubMed
The National Toxicology Program (NTP). Caffeine. Center for the Evaluation of Risks to Human Reproduction (CERHR). Available at: http://cerhr.niehs.nih.gov/common/caffeine.html.
Klebanoff MA, Levine RJ, DerSimonian R, et al. Maternal serum paraxanthine, a caffeine metabolite, and the risk of spontaneous abortion. N Engl J Med 1999;341:1639-44. PubMed
Eskenazi B. Caffeine—filtering the facts. N Engl J Med 1999;341:1688-9. PubMed
Fernandes O, Sabharwal M, Smiley T, et al. Moderate to heavy caffeine consumption during pregnancy and relationship to spontaneous abortion and abnormal fetal growth: a meta-analysis. Reprod Toxicol 1998;12:435-44. PubMed
Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. PubMed
Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
FDA. Proposed rule: dietary supplements containing ephedrine alkaloids. Available at: www.verity.fda.gov (Accessed 25 January 2000).
Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med 1999;220:271-5. PubMed
Briggs GB, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1998.
Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. PubMed
Watson JM, Jenkins EJ, Hamilton P, et al. Influence of caffeine on the frequency and perception of hypoglycemia in free-living patients with type 1 diabetes. Diabetes Care 2000;23:455-9. PubMed
Lloyd T, Johnson-Rollings N, Eggli DF, et al. Bone status among postmenopausal women with different habitual caffeine intakes: a longitudinal investigation. J Am Coll Nutr 2000;19:256-61. PubMed
American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001;108:776-89. PubMed
Sinclair CJ, Geiger JD. Caffeine use in sports. A pharmacological review. J Sports Med Phys Fitness 2000;40:71-9.
Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000;343:1833-8. PubMed
Ali M, Afzal M. A potent inhibitor of thrombin stimulated platelet thromboxane formation from unprocessed tea. Prostaglandins Leukot Med 1987;27:9-13. PubMed
Ardlie NG, Glew G, Schultz BG, Schwartz CJ. Inhibition and reversal of platelet aggregation by methyl xanthines. Thromb Diath Haemorrh 1967;18:670-3. DOI
Olthof MR, Hollman PC, Zock PL, Katan MB. Consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans. Am J Clin Nutr 2001;73:532-8. PubMed
Hartman TJ, Tangrea JA, Pietinen P, et al. Tea and coffee consumption and risk of colon and rectal cancer in middle-aged Finnish men. Nutr Cancer 1998;31:41-8. PubMed
Ferrini RL, Barrett-Connor E. Caffeine intake and endogenous sex steroid levels in postmenopausal women. The Rancho Bernardo Study. Am J Epidemiol 1996:144:642-4. PubMed
Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33:1399-403. PubMed
Horner NK, Lampe JW. Potential mechanisms of diet therapy for fibrocystic breast conditions show inadequate evidence of effectiveness. J Am Diet Assoc 2000;100:1368-80. PubMed
Bracken MB, Triche EW, Belanger K, et al. Association of maternal caffeine consumption with decrements in fetal growth. Am J Epidemiol 2003;157:456-66.. PubMed
Shekelle PG, Hardy ML, Morton SC, et al. Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis. JAMA 2003;289:1537-45.. PubMed
McGowan JD, Altman RE, Kanto WP Jr. Neonatal withdrawal symptoms after chronic maternal ingestion of caffeine. South Med J 1988;81:1092-4.. PubMed
Nehlig A, Debry G. Consequences on the newborn of chronic maternal consumption of coffee during gestation and lactation: a review. J Am Coll Nutr 1994;13:6-21.. PubMed
Massey LK. Is caffeine a risk factor for bone loss in the elderly? Am J Clin Nutr 2001;74:569-70. PubMed
Dreher HM. The effect of caffeine reduction on sleep quality and well-being in persons with HIV. J Psychosom Res 2003;54:191-8.. PubMed
Kockler DR, McCarthy MW, Lawson CL. Seizure activity and unresponsiveness after hydroxycut ingestion. Pharmacotherapy 2001;21:647-51.. PubMed
Nix D, Zelenitsky S, Symonds W, et al. The effect of fluconazole on the pharmacokinetics of caffeine in young and elderly subjects. Clin Pharmacol Ther 1992;51:183. DOI
Greenblatt DJ, von Moltke LL, Perloff ES, et al. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies. Clin Pharmacol Ther 2006;79:125-33. PubMed
Infante S, Baeza ML, Calvo M, et al. Anaphylaxis due to caffeine. Allergy 2003;58:681-2. PubMed
Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J Nutr 1993;123:1611-4. PubMed
Nawrot P, Jordan S, Eastwood J, et al. Effects of caffeine on human health. Food Addit Contam 2003;20:1-30. PubMed
May DC, Jarboe CH, VanBakel AB, Williams WM. Effects of cimetidine on caffeine disposition in smokers and nonsmokers. Clin Pharmacol Ther 1982;31:656-61. PubMed
Abernethy DR, Todd EL. Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. Eur J Clin Pharmacol 1985;28:425-8. PubMed
Brown NJ, Ryder D, Branch RA. A pharmacodynamic interaction between caffeine and phenylpropanolamine. Clin Pharmacol Ther 1991;50:363-71. PubMed
Sanderink GJ, Bournique B, Stevens J, et al. Involvement of human CYP1A isoenzymes in the metabolism and drug interactions of riluzole in vitro. Pharmacol Exp Ther 1997;282:1465-72. DOI
Wahllander A, Paumgartner G. Effect of ketoconazole and terbinafine on the pharmacokinetics of caffeine in healthy volunteers. Eur J Clin Pharmacol 1989;37:279-83. PubMed
Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed
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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 Black Tea and Levothyroxine Sodium Together: Common Questions

Is it safe to take Black Tea with Levothyroxine Sodium?

We do not list a known interaction between Black Tea and Levothyroxine Sodium. 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.

Do Black Tea and Levothyroxine Sodium have any of the same side effects?

Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Should I take Black Tea and Levothyroxine Sodium at the same time of day?

At least one FDA label for a product containing Levothyroxine Sodium 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 Sodium on its own and move Black Tea 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.

How was the Black Tea and Levothyroxine Sodium combination checked?

Interactions in our licensed database are recorded against drug classes. Levothyroxine Sodium is filed under 3 classifications, and Black Tea has documented interactions with 46 drug classes — none of Levothyroxine Sodium's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Black Tea interact with any other medications?

Yes. Black Tea has 694 documented drug interactions in our database — Levothyroxine Sodium is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Levothyroxine Sodium interact with any supplements?

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

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

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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.