How to Take Levothyroxine: Patient Information Guide
When to Take Your Medication
Take levothyroxine once daily on an empty stomach, one-half to one hour before breakfast, with a full glass of water. 1
Alternative Timing Option
- Bedtime dosing is an effective alternative if morning dosing is difficult for you. 2
- A clinical trial showed that taking levothyroxine at bedtime (at least 2-3 hours after your last meal) actually improved thyroid hormone levels compared to morning dosing, though quality of life was similar with either approach. 2
- Choose whichever time works best for your schedule, but be consistent. 1
Why Timing Matters
- Your stomach must be empty for optimal absorption of the medication. 1
- Taking it with food significantly reduces how much medication your body absorbs. 1
- Consistency in timing helps maintain stable thyroid hormone levels. 3
Foods and Drinks to Avoid
Timing Restrictions Around Levothyroxine
Wait at least 30-60 minutes after taking levothyroxine before eating or drinking anything except water. 1
Specific Foods That Interfere With Absorption
Avoid these foods within 4 hours of taking your medication:
- Soy products (soy milk, tofu, soy-based infant formula) - these significantly decrease levothyroxine absorption 1
- High-fiber foods in large amounts may affect absorption 3
- Grapefruit juice can interfere with medication absorption 3
- Coffee - while not absolutely prohibited, it may reduce absorption if taken too close to your dose 1
Medications and Supplements to Separate From Levothyroxine
Take these at least 4 hours before or after your levothyroxine dose: 1
- Iron supplements (including multivitamins with iron) 1
- Calcium supplements (including calcium-fortified foods and antacids containing calcium) 1
- Antacids (especially those containing aluminum or magnesium) 1
- Proton pump inhibitors for acid reflux 3
Why This 4-Hour Gap Matters
These substances bind to levothyroxine in your digestive tract, preventing your body from absorbing the medication properly. 1 Even if you feel fine, you may not be getting the full dose your doctor prescribed. 3
Important Swallowing Instructions
Swallow tablets whole with a full glass of water to avoid choking or gagging. 1
For Those Who Cannot Swallow Pills
- Crush the tablet immediately before taking it 1
- Mix the crushed tablet in 5-10 mL (1-2 teaspoons) of water 1
- Take the entire suspension immediately by spoon or dropper 1
- Never store the crushed medication - it must be taken right away 1
- Make sure you swallow all of the mixture 1
What to Expect From Treatment
Timeline for Improvement
- It may take 4-6 weeks before you notice improvement in your symptoms. 1
- Your doctor will check your blood levels after 6-8 weeks to see if your dose needs adjustment. 3
- Do not expect immediate results - thyroid hormone replacement works gradually. 1
This Is Lifelong Treatment
- Levothyroxine replaces a hormone your thyroid gland should normally produce. 1
- Most patients need to take this medication for life. 1, 4
- Never stop taking your medication without consulting your doctor, even if you feel better. 3
Critical Safety Information
What Levothyroxine Is NOT For
Levothyroxine should never be used for weight loss or obesity treatment in people with normal thyroid function. 1 Taking doses larger than needed can cause serious or life-threatening toxicity, especially when combined with diet pills or stimulants. 1
When to Call Your Doctor Immediately
Contact your healthcare provider if you experience: 1
- Rapid or irregular heartbeat 1
- Chest pain or shortness of breath 1
- Excessive sweating or heat intolerance 1
- Tremors, nervousness, or sleeplessness 1
- Severe headache 1
- Unusual weight loss or gain 1
- Persistent diarrhea or vomiting 1
These symptoms may indicate your dose is too high. 3, 1
Special Situations
If You're Pregnant or Planning Pregnancy
- Notify your doctor immediately - your levothyroxine dose will likely need to increase by 25-50% during pregnancy. 3
- Untreated hypothyroidism during pregnancy can harm your baby's development. 3
- Continue taking your medication throughout pregnancy. 3
Before Surgery or Dental Procedures
- Inform your surgeon or dentist that you take levothyroxine. 1
If You Have Diabetes
- Monitor your blood sugar more frequently when starting levothyroxine, as it may affect your glucose levels. 1
- Report any changes to your doctor. 1
If You Take Blood Thinners
- Your clotting status should be checked more frequently. 1
Common Questions
Can I take levothyroxine with my other morning medications?
No - take levothyroxine alone, then wait at least 4 hours before taking iron, calcium, or antacids. 1 Other medications may be taken after the 30-60 minute waiting period, but check with your pharmacist about specific interactions. 1
What if I miss a dose?
Take it as soon as you remember, unless it's almost time for your next dose. Never take two doses at once. 3 Contact your doctor if you miss multiple doses. 3
Will I lose hair?
Some temporary hair loss may occur in the first few months of treatment, but this is usually temporary and will resolve. 1
How should I store my medication?
Store at room temperature (68°F to 77°F), protected from light and moisture. 1 Keep in the original container with the child-resistant cap. 1