Levothyroxine is a commonly prescribed medicine in the UK, used for underactive thyroid. If you have just been prescribed levothyroxine, this page explains what it is, the brands and strengths it comes in, how to take it, and how to have it dispensed and delivered free on the NHS with PillSorted.
This content has been medically reviewed and approved by Zeinab Ardeshir (GPhC 2075730), Superintendent Pharmacist at PillSorted (GPhC-registered online pharmacy 9011258). Last reviewed: 2 July 2026.
What is levothyroxine?
Levothyroxine replaces the thyroid hormone your body is missing when you have an underactive thyroid (hypothyroidism). It is usually taken for life.
Brands and strengths
Levothyroxine is the name of the active ingredient. In the UK it is sold as generic levothyroxine and under brand names including Eltroxin, Vencamil and Evotrox — all contain the same active ingredient and work the same way. Common strengths:
- Levothyroxine 25 microgram tablets
- Levothyroxine 50 microgram tablets
- Levothyroxine 75 microgram tablets
- Levothyroxine 100 microgram tablets
- UK brands: Eltroxin, Vencamil and Evotrox
What levothyroxine is used for
- Underactive thyroid (hypothyroidism)
How to take levothyroxine
Taken once a day on an empty stomach, ideally 30–60 minutes before breakfast, with water. You will have regular blood tests so the dose can be adjusted. Always follow your prescriber’s instructions (BNF).
Side effects
When the dose is right there are usually no side effects. Too much can cause a fast heartbeat, sweating or weight loss — tell your prescriber. This is not a full list — see the patient information leaflet (BNF).
Levothyroxine: frequently asked questions
Yes. Eltroxin is a brand name for levothyroxine; the generic has the same active ingredient.
Food and some drinks reduce how well it is absorbed, so taking it on an empty stomach helps it work reliably.
Yes. If you have an NHS prescription for levothyroxine, you can nominate PillSorted as your NHS pharmacy and we will dispense and deliver it to your door for free.
Get your levothyroxine delivered free on the NHS
If you have an NHS prescription for levothyroxine, PillSorted dispenses and delivers it to your door — completely free. Nominate PillSorted as your NHS pharmacy once, and we take care of your repeat prescriptions from then on.
What you get
- Free delivery, every time — your medicine posted to your door, always free.
- Your whole family, one account — manage everyone’s prescriptions in one place.
- Real pharmacists, every prescription — every order checked by our UK pharmacist team.
How it works
- Choose PillSorted as your NHS pharmacy
- We collect your prescription from your GP
- Your medication is delivered free to your door
Sources: NICE; BNF — Levothyroxine.
This page is for general information only and is not a substitute for advice from your GP or pharmacist. Always take your medicine exactly as prescribed. For advice about your own health, consult a clinician.