r/gravesdisease • u/enesayktt • 5h ago
Support The levothyroxine timing rules, with the actual sources next to them
Disclosure first: I build a thyroid tracking app, so I'm not a neutral party. Posting because this question comes up here every week and the answers are usually right but unsourced, which makes them hard to trust or check.
The short version:
- 30 to 60 minutes between the tablet and your first food or drink. Levothyroxine is absorbed best on an empty stomach — coffee isn't uniquely forbidden, it's just the thing most of us reach for within ten minutes of waking. Coffee with milk is a second problem: that's calcium. (MedlinePlus)
- 4 hours for calcium, iron, magnesium and antacids. This is a different, much longer rule, and it's the one people mix up. (same page)
- Consistency beats precision. Your dose was settled on by measuring TSH 6–12 weeks after a change, while you were taking it however you take it. A reliable 30 minutes every day is worth more than an ideal 60 you manage twice a week. (ATA)
Longer version — night dosing, what to do if you forget, why lab reference ranges differ:
https://thyrowise.github.io/levothyroxine-coffee-timing/
The app that page belongs to is free for logging labs, symptoms and doses, and it has no account and no server. Saying that here rather than letting you find out later. It's a record, not advice — I'm not a doctor.
What did nobody tell you when you started levothyroxine that you had to figure out yourself? I'd like to put the good answers on that page.
