Can grapefruit or other fruits interfere with levothyroxine absorption, and how long should I wait after taking my dose before eating fruit?

Grapefruit and some other foods can interfere with levothyroxine absorption, so it’s best to take levothyroxine on an empty stomach and wait before eating fruit. Grapefruit juice can delay absorption and reduce the amount your body gets, which may make your thyroid levels less stable. ^{[1] [2]} Most labels also advise avoiding food for 30–60 minutes after your dose to maximize absorption. ^{[3] [4]}

How grapefruit affects levothyroxine

• Grapefruit juice may slow down how quickly levothyroxine is absorbed and reduce its bioavailability (the usable amount in your bloodstream). ^{[1] [2]}
• This effect has been specifically noted in official prescribing information for levothyroxine. ^{[1] [2]}

Other foods and supplements that interfere

• Certain high‑fiber foods and components like soybean flour, cottonseed meal, walnuts, and dietary fiber can bind levothyroxine in the gut and decrease absorption. ^{[1] [2]}
• Iron and calcium products (including many antacids and supplements) can also block absorption; separating these by at least 4 hours from levothyroxine is generally recommended. ^{[5] [6]}

Timing with meals and fruit

• Taking levothyroxine in a fasting state keeps thyroid‑stimulating hormone (TSH) more stable and within a tighter target range compared with taking it with breakfast or at bedtime. ^[7]
• Official instructions recommend taking levothyroxine once daily on an empty stomach, about 30–60 minutes before breakfast. ^{[3] [4]}

Practical recommendations

• Aim to take levothyroxine with water only, first thing in the morning, and wait 30–60 minutes before eating any food, including fruit. ^{[3] [4]}
• If you specifically consume grapefruit or grapefruit juice, it would be prudent to avoid it around the time of your dose to minimize reduced absorption. ^{[1] [2]}
• Keep iron, calcium, and antacids at least 4 hours away from your levothyroxine dose. ^{[5] [6]}

Quick reference table

Item	Effect on levothyroxine	What to do
Grapefruit/juice	May delay absorption and reduce bioavailability	Avoid near dosing; wait 30–60 min after dose before eating; consider separating grapefruit to later in the day
Soybean flour, cottonseed meal, walnuts, high dietary fiber	Can bind drug and decrease absorption	Take levothyroxine on empty stomach; keep consistent diet; monitor thyroid labs if diet changes
Iron, calcium, antacids	Decrease absorption	Separate by at least 4 hours from levothyroxine
General meals/breakfast	Raises and adds variability to TSH vs fasting dosing	Take levothyroxine fasting for more stable levels

Bottom line

• For best and most consistent absorption, take levothyroxine with water on an empty stomach and wait 30–60 minutes before eating any food, including fruit. ^{[3] [4]}
• Because grapefruit can reduce levothyroxine’s bioavailability, it’s reasonable to avoid grapefruit products close to your dose; having them later in the day is a safer option. ^{[1] [2]}
• Keep iron, calcium, and antacids at least 4 hours apart from your levothyroxine. ^{[5] [6]}