How to take the Wegovy pill and levothyroxine
The Wegovy pill and levothyroxine both need to be taken first thing in the morning on an empty stomach, which is why it’s not recommended to take them together.
The Wegovy pill only absorbs properly when your stomach is empty. You take it as soon as you wake up, swallow it whole with a small sip of water (no more than 120 ml), then wait at least 30 minutes before eating, drinking anything else, or taking any other tablet, which includes levothyroxine.1
Levothyroxine also needs to be taken on an empty stomach, 30 to 60 minutes before food to be effective.2
So the two medications can’t be swallowed together. Your prescriber will help you choose the approach that suits you.
Option 1: move levothyroxine to bedtime
You take the Wegovy pill in the morning as normal, and your levothyroxine at bedtime, at least three hours after your last meal.
Taking levothyroxine at bedtime is a recognised alternative to the morning, and moving it there removes any potential interactions with the Wegovy pill completely.
Option 2: keep both in the morning, in order
If you’d rather keep levothyroxine in the morning, we recommend you take it second, after the Wegovy pill’s 30-minute window:
- Take the Wegovy pill as soon as you wake up, with a small sip of water
- Wait at least 30 minutes, with no food, drink, or other tablets
- Take your levothyroxine with water
- Wait a further 30 minutes or so before breakfast, tea, or coffee
This approach maintains a gap between the two medications rather than taking them together.
Taking them at the same time increases thyroxine absorption, so by waiting 30 minutes before taking levothyroxine after the Wegovy pill, you’re reducing the chance of them interacting.
Following this schedule will mean waiting over an hour before you can have breakfast or drink your morning coffee.
What to keep separate from levothyroxine
Whichever option you choose, keep calcium, iron, and antacids at least 4 hours apart from your levothyroxine, as they reduce how much you absorb. Soya and high-fibre meals taken at the same time can interfere too.2
Does the Wegovy pill affect levothyroxine?
Yes, and this is the main difference between the pill and the injection.
The Wegovy pill is oral semaglutide, so it shares the same fasted dosing requirements as levothyroxine, and taking the two together can change how much thyroxine you absorb.
In one study on Rybelsus – another formulation of oral semaglutide used to treat type 2 diabetes – a single dose of levothyroxine taken with oral semaglutide increased total thyroxine exposure by 33%, while the peak level was unchanged.1
Because of this possible interaction, the Wegovy pill’s prescribing information advises monitoring thyroid levels when semaglutide and levothyroxine are taken together.1
More thyroxine in your system lowers how much levothyroxine you need, just as weight loss does.
If your dose stays the same, you can end up with too much thyroid hormone, which causes palpitations, anxiety, and trouble sleeping. A blood test can detect this, so your prescriber can lower your dose.
Separating the two doses, or moving levothyroxine to bedtime, will reduce the likelihood of medication interactions, helping your thyroxine levels remain stable.
Even so, your thyroid levels are worth checking in the first few months, as you may need a lower levothyroxine dose with weight loss.
Symptoms worth watching for
We recommend paying attention to the following symptoms, as they likely suggest your levothyroxine levels may need to change:
- A racing heart, anxiety, tremor, sweating, or trouble sleeping, which can mean your levels are too high, either from the absorption change or from weight loss reducing how much levothyroxine you need
- Returning fatigue, feeling colder, constipation, or low mood, which can mean your levels have dropped
None of these is an emergency on their own, but they’re worth mentioning to your GP. A blood test usually shows whether your thyroid levels have changed.
TSH monitoring on the Wegovy pill
NICE guidance on thyroid disease recommends measuring TSH (the hormone that tells your thyroid how much to produce) every three months until your level is stable, then once a year.4
Starting the Wegovy pill would be considered a meaningful change, so it’s sensible to bring your TSH check forward to roughly six to eight weeks after starting, and again after each dose increase. Ask your GP for this rather than waiting for your annual review.
Your TSH should stay in the target range your prescriber has set for you. If it decreases, you may be absorbing more levothyroxine, or you may have lost enough weight to reduce your dose. If it increases, your dose may need to be adjusted the other way.
The standard test is TSH. If your symptoms don’t match your TSH result, your GP may also check free T4 (the main hormone your thyroid produces).
NICE doesn’t recommend routine free T3 testing for an underactive thyroid, because your free T3 levels rarely change your treatment plan.4
Weight loss and your levothyroxine dose
A study in the Journal of Clinical Endocrinology & Metabolism found that lean body mass, not fat mass, is the strongest predictor of your thyroid hormone requirement, which is why your requirement often decreases as you lose weight.5
If you lose 10% to 15% of your body weight, your prescriber may reduce your levothyroxine to keep your TSH in range.
The Wegovy pill produces substantial weight loss. In the OASIS 4 trial, people taking oral semaglutide 25 mg lost an average of 13.6% of their body weight over 64 weeks, and those who completed the full course reached an average of 16.6%.3
You may need less levothyroxine while you’re taking the Wegovy pill.
Taking the two tablets close together increases the amount of thyroxine you absorb, and losing weight reduces the amount of levothyroxine your body needs.
Your prescriber will check your thyroid levels early in your treatment with the Wegovy pill and may lower your dose.
If your prescriber reduces your dose, they’ll usually retest your TSH six to eight weeks later. Changes are typically small, often a 25 microgram change.
Don’t adjust your own dose because thyroid hormone has a long half-life, and it’s easy to take too much.
If you have Hashimoto’s disease, the most common cause of an underactive thyroid in the UK, weight loss won’t reverse the underlying autoimmune process. You’ll still need levothyroxine; the dose may simply be lower.
Eating well on both medications
The Wegovy pill reduces appetite and quietens food noise, but the aim isn’t to eat as little as possible, as this can impact thyroid function and increase the risk of muscle loss and nutrient deficiencies.
Eating three balanced meals a day helps preserve muscle, supports thyroid function, and keeps your energy levels even.
We recommend a whole-food diet that provides enough protein, fibre, fat, and complex carbohydrates, and limits ultra-processed foods.
Second Nature’s balanced plate is a useful starting point: half your plate vegetables, a quarter protein, a quarter complex carbohydrates, plus a serving of fat.
Protein at every meal
Protein protects muscle mass during weight loss and helps you feel fuller for longer.
A useful visual is a portion around the size of your palm at each meal: eggs, fish, chicken, turkey, lean red meat, Greek yoghurt, beans, lentils, or tofu.
Iodine and selenium: how much you need
Your thyroid uses iodine and selenium to make its hormones.
Adults need 140 micrograms of iodine a day,11 and 75 micrograms of selenium for men or 60 micrograms for women.12
If you take levothyroxine, your thyroid hormone is already being replaced by the tablet, so the aim isn’t to consume excessive amounts of iodine. It’s to meet the daily requirements and avoid the extremes, because too much iodine is as problematic as too little.
Where to find iodine
Milk and dairy are the main sources of iodine in the UK diet, and white fish contains far more than oily fish.13
| Food |
Portion |
Average iodine (mcg) |
| Haddock |
120 g |
390 |
| Cod |
120 g |
230 |
| Scampi |
170 g |
160 |
| Cow’s milk |
200 ml |
50 to 100 |
| Yoghurt |
150 g |
50 to 100 |
| Plaice |
130 g |
30 |
| Egg |
1 egg |
25 |
| Cheese |
40 g |
15 |
| Salmon fillet |
100 g |
14 |
| Canned tuna |
100 g |
12 |
Iodine content varies with soil, season, and farming, so treat these as a guide rather than exact amounts. Iodine content in milk is higher in winter.13
A 200 ml glass of milk and one egg take most adults to around half the daily amount, and a portion of white fish once or twice a week covers the rest.
If you follow a vegan diet, iodine is harder to get through your diet, and not all plant milks are fortified with it. Check the label, and you might also need to consider a supplement.11
Where to find selenium
Brazil nuts are by far the richest source of selenium, with 68 to 91 micrograms per nut, more than a full day’s requirement.14
Six nuts would take you over the 400-microgram daily upper limit for adults, so one or two a day is plenty.14
Fish, shellfish, meat, eggs, and lentils also contain selenium, and a varied diet based on whole foods will naturally support healthy selenium intake without requiring much attention.12
When more isn’t better
Too much iodine can disrupt thyroid function, and if you already have a thyroid condition, an intake that’s fine for most people may affect you. The BDA advises adults not to exceed 600 micrograms a day.13
Kelp and brown seaweed are the most common cause of accidental excess. Their iodine content is very high and varies enormously, so they aren’t a reliable source, and the BDA advises eating them no more than once a week.13
If you have an underactive thyroid, kelp supplements are worth avoiding altogether unless your prescriber has recommended one.
Too much selenium causes selenosis, which first appears as hair loss and brittle nails. Supplements above 350 micrograms a day are the usual cause.12
For most people, you should be able to get enough iodine and selenium from your diet, and supplements aren’t necessary in most cases.
There’s no need to avoid broccoli, kale, or cabbage, as there’s no strong evidence they harm thyroid function in regular dietary amounts.
Eating three balanced meals when you’re not hungry
The Wegovy pill can reduce our hunger to the point that we might not feel like eating at all.
However, skipping meals or eating too little can increase the risk of muscle and hair loss, nutrient deficiencies, and low energy levels, as our bodies struggle to meet our everyday needs.
So, it’s essential to eat three balanced meals a day, even if you’re not hungry.
On days you’re not feeling that hungry, focus on easier-to-digest whole foods:
- Greek yoghurt with berries and nut butter
- Scrambled eggs and spinach on sourdough
- A smoothie with spinach, fruit, Greek yoghurt, and protein powder
- Soups with boiled eggs (or another protein source on the side) and toast
You could also try batch cooking once a week so you have meals ready to reheat on days you don’t feel like cooking.
Staying active
Movement supports weight loss, helps preserve muscle, and counteracts the fatigue that an underactive thyroid can cause.
We recommend focusing on building activity into your day as a habit first, before setting more ambitious movement targets.
Challenges like the NHS’ Couch to 5k are a good example of building something up slowly so that the habit sticks in the long term.
Running or walking a 5k doesn’t have to be the goal; more importantly, it’s about moving in ways you feel capable of and enjoy.
Research on habit formation suggests it takes an average of 66 days for a new behaviour to feel automatic.6
We’d recommend starting small and linking the habit to something you already do, like a 10-minute walk after dinner. Gradually do a little more as it feels manageable.
Resistance training will help to maintain muscle mass and improve muscle function while on GLP-1 medications, and it’s something you gradually introduce once physical activity is a habit.
Our members love the concept of exercise snacking, where you introduce small amounts of movement into your day, such as calf raises while the kettle boils or squats in front of the TV.
The Wegovy pill versus the injections
| Feature |
Wegovy pill (oral semaglutide) |
Wegovy injection (semaglutide) |
Mounjaro injection (tirzepatide) |
| How you take it |
A daily tablet, first thing on an empty stomach |
A once-a-week injection, any time of day |
A once-a-week injection, any time of day |
| Timing clash with levothyroxine |
Yes. Both require a morning fasting routine, and the pill needs 30 minutes clear before any other tablet. |
No |
No |
| Listed levothyroxine interaction |
Yes. Taken together, they increased thyroxine exposure by 33%; the prescribing information advises monitoring thyroid levels.1 |
No listed interaction |
No listed interaction |
| Average weight loss in trials |
13.6% at 64 weeks on 25 mg (OASIS 4)3 |
14.9% at 68 weeks on 2.4 mg (STEP 1); 20.7% at 72 weeks on 7.2 mg (STEP UP)7,8 |
20.9% at 72 weeks on 15 mg (SURMOUNT-1)9 |
Frequently asked questions
Can you take the Wegovy pill and levothyroxine at the same time?
No, not at the same time. The Wegovy pill needs 30 minutes clear before any other tablet, and taking levothyroxine together with oral semaglutide increases thyroxine absorption by 33%.1
Take the Wegovy pill first with a sip of water, wait at least 30 minutes, then take your levothyroxine. Many people find it simpler to move levothyroxine to bedtime instead.
Is it easier to take levothyroxine at night on the Wegovy pill?
For many people, yes. Taking levothyroxine at bedtime, at least 3 hours after your last meal, works as well as taking it in the morning and completely eliminates the risk of interaction with the Wegovy pill.
Does the Wegovy pill increase thyroxine levels by 33%?
Taking levothyroxine at the same time as oral semaglutide increased total thyroxine exposure by 33%, while the peak level remained unchanged.1
Your thyroid levels should be monitored after starting.
How often should I get my thyroid checked on the Wegovy pill?
NICE recommends every three months until your level is stable, then once a year.4
When starting the Wegovy pill or moving up a dose, ask your GP to bring a TSH check forward to roughly six to eight weeks later.
Will I need a lower dose of levothyroxine on the Wegovy pill?
Possibly. Taking the Wegovy pill and levothyroxine close together increases how much thyroxine you absorb, and losing weight reduces how much levothyroxine your body needs, so both tend to lower your dose.1,5
Your GP will adjust your prescription based on your TSH. Don’t change the dose yourself.
Can I take the Wegovy pill if I have Hashimoto’s?
Yes. Hashimoto’s is the most common cause of an underactive thyroid in the UK and isn’t a reason to avoid the Wegovy pill.
You’ll continue your levothyroxine, with the dosing schedule planned around the pill and the usual TSH monitoring after starting.
What if I’m sick soon after taking the Wegovy pill or my levothyroxine?
If you vomit within 30 minutes of a tablet, it may not have been fully absorbed.
Speak to your GP or pharmacist about whether to retake it, and flag persistent nausea to your prescriber, as it can affect both medications.
Would the Wegovy injection be simpler with levothyroxine?
In terms of timing your doses, yes. The injection isn’t a tablet and has no listed interaction with levothyroxine.
Still, the pill suits people who prefer to avoid injections, so we’d recommend speaking with your prescriber to see what option is best for you.
Can the Wegovy pill cause thyroid problems?
There’s no evidence that it causes thyroid problems in people with a normal thyroid.
In studies in rodents, semaglutide caused a type of thyroid tumour, but humans have very few of the receptors involved, and large human trials haven’t shown a consistent increase in thyroid cancer risk.
Unlike the US label, the UK prescribing information doesn’t list a personal or family history of medullary thyroid cancer as a formal contraindication, though your prescriber will still take a full history before starting.1
Take home message
The Wegovy pill and levothyroxine can be taken together, but not at the same time.
The pill has to be taken on its own, with 30 minutes clear before any food, drink, or other tablet, including levothyroxine.
Taking the two together also increases thyroxine absorption by 33%, so they shouldn’t be swallowed at the same time.
The simplest solution for many people is to take levothyroxine at bedtime, which removes the risk of interaction between the medications.
If you’d rather keep it in the morning, take the Wegovy pill first, wait 30 minutes, then take your levothyroxine.
Your thyroid levels should be checked in the first few months because weight loss will inherently lower your levothyroxine dose.
Second Nature combines medication with structured habit-change support from registered dietitians and coaches, built around the balanced plate of vegetables, protein, complex carbohydrates, and healthy fats.
A 2025 study published in JMIR Formative Research found that active subscribers on Second Nature’s GLP-1-supported programme lost an average of 19.1% of their body weight at 12 months, with 77.7% achieving at least 10% weight loss.10
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
