UK weight loss medicine prices
When tiredness is worth an appointment
The NHS says to see a GP if you have been tired for a few weeks and do not know why, if it affects your daily life, if it comes with other symptoms such as weight loss or mood changes, or if someone has told you that you gasp, snort or choke in your sleep. That is a low bar on purpose. You do not need to prove you are exhausted enough.
Women carry several causes men do not, including periods, pregnancy and the menopause, and some conditions that are more common in women, such as an underactive thyroid and autoimmune disease. This page maps the common ones and links to the guides that go deeper.
The common causes, and what points to each
| Cause | Clues | What to ask for | More detail |
|---|---|---|---|
| Low iron | Heavy periods, breathless on stairs, hair shedding, restless legs | Full blood count and ferritin | Iron guide |
| Underactive thyroid | Feeling cold, constipation, dry skin, weight gain | TSH | Thyroid guide |
| Perimenopause or menopause | Age 40 plus, changing periods, night sweats, broken sleep | A GP review of your symptoms | Menopause guides |
| Sleep apnoea | Snoring, pauses in breathing, morning headaches | Referral for an overnight sleep study | Sleep guide |
| Low mood or depression | Low mood for 2 weeks or more, loss of enjoyment | A talk with the GP, or NHS talking therapies | NHS low mood page |
| Diabetes | Thirst, passing urine often, weight loss | HbA1c blood test | NHS tiredness page |
| Coeliac disease | Bloating, diarrhoea, mouth ulcers, anaemia | Coeliac antibody blood test, while still eating gluten | NHS coeliac page |
| Low B12 | Vegan diet, metformin, acid tablets, past stomach surgery | B12 and folate | NHS B12 page |
| Eating or drinking too little | On a weight loss medicine, small portions | A food and fluid diary | Eating too little guide |
Iron: the first test to ask for
Heavy periods are the usual reason women run short of iron. Ferritin, the iron store, falls before haemoglobin does, so you can be low on iron with a normal blood count. Our iron guide explains the ferritin number NICE uses and how to take tablets with less stomach upset.
Thyroid
An underactive thyroid is far more common in women than in men, and its symptoms copy both weight gain and weight loss medicine side effects. A TSH blood test settles it. The thyroid guide covers the test and what to do if you already take levothyroxine.
Menopause and perimenopause
The NHS lists hormone changes, including the menopause, among the common causes of tiredness. Night sweats break sleep, and low mood and brain fog add to the drain. Our brain fog and mood guide and the perimenopause guide cover the symptoms and treatment.
Sleep apnoea
In sleep apnoea, breathing stops and starts through the night. It is often missed in women because the textbook picture is a man who snores loudly. The NHS says a GP can refer you to a sleep clinic, and the overnight test can usually be done at home. Bring a partner to the appointment if they have seen you stop breathing. The sleep guide explains how weight loss helps.
Low mood
Low mood can make you tired and break sleep. The NHS says low mood lasting 2 weeks or more may be a sign of depression. Adults can self-refer to NHS talking therapies in England without seeing a GP first. If you have thoughts of harming yourself, get urgent help. The NHS page lists where to go, and Samaritans answer on 116 123.
Coeliac disease and B12
The NHS coeliac page says anyone with prolonged tiredness, unexplained anaemia, or a diagnosis of IBS or autoimmune thyroid disease should be tested. Keep eating gluten until the blood test is done, or the result may be wrong. Do not start a gluten-free diet until a specialist confirms the diagnosis.
Vitamin B12 deficiency is often caused by pernicious anaemia, an autoimmune condition. The NHS also lists a vegan diet without supplements or fortified foods, stomach surgery, and medicines including metformin and the acid-reducing tablets called proton pump inhibitors. Many women with PCOS take metformin, so mention it.
Coeliac disease, pernicious anaemia and autoimmune thyroid disease are all autoimmune conditions, which are more common in women. Our autoimmune guide covers the wider group.
Tired on a weight loss jab
Fatigue is a listed side effect. The Mounjaro leaflet lists "feeling tired" as common in people treated for weight management. The same leaflet warns that sickness and diarrhoea can cause dehydration, and advises drinking plenty of fluids.
Before you put tiredness down to the medicine, check three things. Are you eating enough protein and total food? Our eating too little guide sets out the warning signs. Are you drinking enough? The hydration guide has targets. And has anyone tested your iron, thyroid and B12? Eating less can lower iron intake while periods keep taking it out.
What GPs test, and what they find
A 2025 audit in the Annals of Clinical Biochemistry looked at 16,889 GP blood test requests for tiredness in 2019, measured against NICE's summary for tiredness in adults. It found some tests were often skipped.
| Test | How often GPs requested it | How often the result was abnormal |
|---|---|---|
| Full blood count | 89% | 23% |
| Thyroid (TSH) | 80% | 10% |
| Ferritin (iron store) | 9.4% | 26% |
| Coeliac antibody (IgA TTG) | 3.2% | 3% |
| HbA1c (diabetes) | 2.8% | 59% |
Ferritin was requested for fewer than 1 in 10 people, yet abnormal in about 1 in 4 of those tested. If you have periods or eat less than you used to, ask for it by name.
What to say at the appointment
- Say how long you have been tired and what it stops you doing.
- Mention periods, pregnancy, menopause symptoms, snoring, mood and any weight loss medicine.
- List every medicine and supplement, including metformin, acid tablets and biotin.
- Ask: "Could you check a full blood count, ferritin and TSH? Should I also have HbA1c, coeliac antibodies or B12?"
- Ask for the numbers, not only "normal", and when to come back if nothing is found.
The GP preparation guide has a symptom diary template. If tests come back normal and you are still exhausted after 3 months, the NHS says ME/CFS is one of the conditions a GP may consider.
Get urgent help if tiredness comes with chest pain, severe breathlessness, fainting, or thoughts of harming yourself. Call 999 for chest pain or collapse. Call 111 if you are unsure.
Paying for your own medicine? The lowest first-order prices today, with delivery included: Mounjaro from £89.00, Wegovy from £44.00, Wegovy pill from £52.99, Foundayo from £49.00.
Compare every price Discount codesSources
- Why am I tired all the time? (NHS)
- Tired all the time: what general practitioners request and find in patients with tiredness/fatigue (Handjiev, Nobes and Murphy, Annals of Clinical Biochemistry, 2025)
- Coeliac disease: diagnosis (NHS)
- Vitamin B12 or folate deficiency anaemia: causes (NHS)
- Obstructive sleep apnoea: diagnosis (NHS)
- Low mood and depression (NHS)
- Mounjaro patient information leaflet (Eli Lilly, via the electronic medicines compendium)