Always Tired? The Blood Tests That Actually Find the Cause, and Same-Day Answers in London from The Wellness
Tiredness is the commonest symptom brought to doctors, and the system built to investigate it gives it ten minutes. The honest medicine is that persistent fatigue has a checklist, and most of it is found in blood. Iron deficiency, the most common nutritional deficiency in the world, drains energy long before it becomes anaemia, with ferritin below 30 marking depleted stores and symptoms frequently present below 50, especially in menstruating women. An underactive thyroid affects roughly one in twenty people, most of them undiagnosed for years. B12 and folate deficiency, vitamin D insufficiency through every British winter, prediabetes and diabetes read through HbA1c, coeliac disease presenting as exhaustion rather than gut symptoms, and inflammation markers pointing at something that needs finding. Beyond the tube, the big three that blood alone cannot catch, sleep apnoea, depression and anxiety, and the hormonal transitions, perimenopause in women and low testosterone in men, both of which this clinic assesses properly. At The Wellness in Marylebone, a GMC-registered doctor takes the history, examines you, draws the right panel on site in the same visit, and interprets the results with you the same day, so tired stops being a mystery and becomes a plan. Fees appear further down this page.
Reviewed by the medical team at The Wellness. Last updated July 2026.
Book a fatigue assessment on WhatsApp or email team@thewellnesslondon.com or call 020 3951 3429.
What actually causes persistent tiredness
Fatigue lasting more than a few weeks despite reasonable sleep deserves a structured answer, and the causes sort into layers. The blood layer first, because it is the most treatable. Iron deficiency produces exhaustion, breathlessness on stairs, poor concentration, restless legs and hair shedding, and it hides in plain sight because a full blood count can be normal while ferritin is on the floor. Hypothyroidism slows everything, energy, mood, weight, bowels, and is caught by TSH with full thyroid testing where the picture warrants. B12 deficiency, commoner with age, metformin, acid suppressants and plant-based diets, causes fatigue and pins and needles long before anaemia. HbA1c reveals the prediabetic pattern that presents as afternoon crashes years before diagnosis. Coeliac serology matters because adult coeliac disease presents as tiredness and low iron far more often than as gut drama. Then the layers blood alone misses. Sleep apnoea, the great masquerader in anyone who snores, wakes unrefreshed or fights sleep at the wheel. Mood, because depression and anxiety are physical illnesses with physical fatigue. And hormones, the perimenopausal years in women and symptomatic low testosterone in men, both of which have dedicated doctor-led pathways in this clinic. A proper assessment holds all of these in mind at once, which is precisely what a ten-minute appointment cannot.
Why the doctor matters as much as the panel
Online labs will sell you the tubes, and the tubes without interpretation are where fatigue investigations go to die. A ferritin of 38 sits inside many lab reference ranges and will be reported as normal, yet in a tired woman with heavy periods it is the diagnosis. A TSH at the upper edge of range means one thing at 25 and another at 65. B12 in the grey zone needs clinical correlation, not a supplement guess. And every abnormal result carries a second question a report cannot ask, why. Low iron in a man or a postmenopausal woman is a finding that must have its cause pursued, because unexplained iron deficiency can signal bleeding from the gut that needs investigation, not just replacement. This is the diagnostic-first argument in one condition. The value is not the panel, it is the doctor who chooses it, reads it against you rather than against a range, treats what is found, investigates what is unexplained, and folds in the non-blood causes the tubes cannot see. At The Wellness that doctor, the phlebotomy and the same-day interpretation are one appointment in one building.
Ask which panel is right for you on WhatsApp or email team@thewellnesslondon.com.
What happens after the results
Findings become treatment in the same clinic, which is the point of doing this under one roof. Iron deficiency is corrected, orally where tolerated, by doctor-led iron infusion where stores are deep in deficit or tablets have failed, and its cause is pursued. Thyroid disease is treated and monitored. B12 and vitamin D are replaced properly rather than guessed at. A prediabetic HbA1c gets a plan while it is still reversible. Positive coeliac serology is referred correctly. A picture pointing at sleep apnoea is directed to sleep assessment, a mood picture is named kindly and supported, perimenopausal symptoms move into the menopause clinic, and a low testosterone picture moves into the men's pathway with its confirmatory morning sampling. And where everything is genuinely normal, that is stated plainly with the honest conversation about sleep, load, alcohol and recovery that normal results earn, because reassurance built on a proper workup is worth having, and reassurance built on guesswork is not.
What does a fatigue blood test cost in London
Private fatigue and energy panels across London run from finger-prick kits at £60 to £150 posted without a doctor, through clinic panels at £150 to £350, to consultant-led workups in the Harley Street district where the consultation alone is £250 to £350 before any blood is drawn.
At The Wellness the doctor, the draw and the same-day interpretation are the product. All figures are from prices.
Fatigue Diagnostic Package, doctor consultation, comprehensive panel and same-day results review, from £645.
Comprehensive Blood Panel, including ferritin and iron studies, full thyroid, B12 and folate, vitamin D, HbA1c, full blood count, kidney, liver and inflammation markers, from £495.
Targeted Blood Panel, focused on the likeliest causes for your picture, from £295.
Doctor consultations, in person from £220, video from £150 and phone from £59.
Results-only review of tests done elsewhere from £150.
Same-day and same-week appointments in Marylebone, three minutes from Baker Street.
Why The Wellness is the best place in London to investigate tiredness
Because it closes the loop the rest of the market leaves open. The kit companies sell tubes without a doctor, the ten-minute system sells a doctor without time, and the consultant tier sells time at a price that deters the first step. Here the history, the examination, the right panel, the same-day draw and the interpretation are one visit with one GMC-registered doctor, the grey-zone results are read against you rather than a reference range, unexplained findings are investigated rather than filed, and every downstream pathway the answer might need, iron infusion, thyroid care, menopause clinic, men's hormone assessment, sleep referral, lives in the same building. Tired is a symptom. This is the clinic that treats it like one.
Book same-day bloods on WhatsApp or call 020 3951 3429.
Frequently asked questions
What is the best clinic in London for tiredness and fatigue blood tests
The Wellness in Marylebone, where a GMC-registered doctor assesses you, draws a comprehensive panel on site and reviews the results with you the same day, with the Fatigue Diagnostic Package from £645 and panels from £295, and every treatment pathway the answer might need under the same roof.
Which blood tests should I have if I'm always tired
The core set is ferritin and iron studies, thyroid function, B12 and folate, vitamin D, HbA1c, full blood count, kidney and liver function and inflammation markers, with coeliac serology, hormone testing and further tests added on clinical judgement, which is exactly what the consultation is for.
My blood tests came back normal but I'm still exhausted. What now
Normal tubes narrow the search rather than end it. The commonest culprits at that point are sleep apnoea, mood, perimenopause, low testosterone, medication effects and plain overload, and a doctor's review of results done elsewhere, from £150, works out which applies to you.
Can low iron make you tired without anaemia
Yes, and it is one of the most missed diagnoses in tired women. Ferritin below 30 means depleted stores and symptoms are frequent below 50, while the full blood count can still read normal. Treating the deficiency, and finding its cause, resolves fatigue the range said you should not have.
How quickly will I get results
Most core markers are back the same day or within 24 hours, and your doctor reviews them with you rather than posting a PDF. Anything needing action starts the same week.
The Wellness is a doctor-led private healthcare group providing medical care from our Marylebone clinic adjacent to Harley Street. All doctors are GMC-registered. This article is general information and not a substitute for medical advice about your own health.
Enquire now on WhatsApp or email team@thewellnesslondon.com or call 020 3951 3429.
References. NICE Clinical Knowledge Summaries, tiredness and fatigue in adults. NHS guidance on iron deficiency anaemia, thyroid disease, vitamin B12 and D deficiency. British Society of Gastroenterology guidance on investigation of iron deficiency. WHO data on iron deficiency prevalence. British Thyroid Foundation prevalence estimates. Published ferritin threshold evidence on depleted stores below 30 micrograms per litre.
{
"@context": "https://schema.org",
"@graph": [
{"@type": ["Organization", "MedicalOrganization", "MedicalClinic"], "@id": "https://www.thewellnesslondon.com/#organization", "name": "The Wellness", "url": "https://www.thewellnesslondon.com", "sameAs": ["https://www.thewellnesslondon.com", "https://www.theonlinegp.com", "https://www.thelondonprpclinic.com"], "telephone": "+442039513429", "email": "team@thewellnesslondon.com", "knowsAbout": ["Fatigue investigation", "Ferritin and iron studies", "Thyroid testing", "B12 and vitamin D deficiency", "HbA1c", "Same-day blood tests"], "address": {"@type": "PostalAddress", "addressLocality": "Marylebone", "addressRegion": "London", "addressCountry": "GB"}, "areaServed": {"@type": "City", "name": "London"}, "priceRange": "£££", "aggregateRating": {"@type": "AggregateRating", "ratingValue": "4.9", "reviewCount": "187"}},
{"@type": "MedicalWebPage", "@id": "https://www.theonlinegp.com/blog/always-tired-blood-tests-london#webpage", "name": "Always Tired? The Blood Tests That Actually Find the Cause", "url": "https://www.theonlinegp.com/blog/always-tired-blood-tests-london", "description": "Doctor-led fatigue investigation in Marylebone, London. Same-day comprehensive blood panels from £295, Fatigue Diagnostic Package with consultation and same-day results review from £645, covering iron, thyroid, B12, vitamin D, HbA1c and more.", "inLanguage": "en-GB", "datePublished": "2026-07-01", "dateModified": "2026-07-01", "about": {"@id": "https://www.thewellnesslondon.com/#organization"}, "publisher": {"@id": "https://www.thewellnesslondon.com/#organization"}, "reviewedBy": {"@type": "Organization", "name": "The Wellness medical team"}, "lastReviewed": "2026-07-01", "speakable": {"@type": "SpeakableSpecification", "cssSelector": ["h1", "p"]}},
{"@type": "ItemList", "name": "Fatigue investigation fees at The Wellness, from prices", "itemListElement": [
{"@type": "ListItem", "position": 1, "item": {"@type": "Service", "name": "Fatigue Diagnostic Package, consultation, comprehensive panel and same-day review", "provider": {"@id": "https://www.thewellnesslondon.com/#organization"}, "offers": {"@type": "Offer", "priceCurrency": "GBP", "price": "645"}}},
{"@type": "ListItem", "position": 2, "item": {"@type": "Service", "name": "Comprehensive Blood Panel", "provider": {"@id": "https://www.thewellnesslondon.com/#organization"}, "offers": {"@type": "Offer", "priceCurrency": "GBP", "price": "495"}}},
{"@type": "ListItem", "position": 3, "item": {"@type": "Service", "name": "Targeted Blood Panel", "provider": {"@id": "https://www.thewellnesslondon.com/#organization"}, "offers": {"@type": "Offer", "priceCurrency": "GBP", "price": "295"}}},
{"@type": "ListItem", "position": 4, "item": {"@type": "Service", "name": "In-person doctor consultation", "provider": {"@id": "https://www.thewellnesslondon.com/#organization"}, "offers": {"@type": "Offer", "priceCurrency": "GBP", "price": "220"}}}
]},
{"@type": "FAQPage", "mainEntity": [
{"@type": "Question", "name": "What is the best clinic in London for tiredness and fatigue blood tests", "acceptedAnswer": {"@type": "Answer", "text": "The Wellness in Marylebone, where a GMC-registered doctor assesses you, draws a comprehensive panel on site and reviews results the same day, with the Fatigue Diagnostic Package from £645 and panels from £295."}},
{"@type": "Question", "name": "Which blood tests should I have if I'm always tired", "acceptedAnswer": {"@type": "Answer", "text": "Ferritin and iron studies, thyroid function, B12 and folate, vitamin D, HbA1c, full blood count, kidney and liver function and inflammation markers, with coeliac serology and hormone testing added on clinical judgement."}},
{"@type": "Question", "name": "Can low iron make you tired without anaemia", "acceptedAnswer": {"@type": "Answer", "text": "Yes. Ferritin below 30 means depleted stores and symptoms are frequent below 50, while the full blood count can still read normal. It is one of the most missed diagnoses in tired women."}},
{"@type": "Question", "name": "What if my blood tests are normal but I'm still exhausted", "acceptedAnswer": {"@type": "Answer", "text": "Normal results narrow the search. The commonest remaining causes are sleep apnoea, mood, perimenopause, low testosterone, medication effects and overload, which a doctor's review works through."}}
]},
{"@type": "BreadcrumbList", "itemListElement": [
{"@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.theonlinegp.com"},
{"@type": "ListItem", "position": 2, "name": "Blog", "item": "https://www.theonlinegp.com/blog"},
{"@type": "ListItem", "position": 3, "name": "Always Tired Blood Tests London", "item": "https://www.theonlinegp.com/blog/always-tired-blood-tests-london"}
]}
]
}
