Comparison · Function Health vs UK options
Function Health is the most talked-about blood testing membership in America: 100-plus biomarkers for $365 a year, a mid-year retest, and a dashboard your podcast of choice will not stop mentioning. If you are searching for it from the UK, here is the short version: you cannot use it here. Its blood testing runs through Quest Diagnostics, a US laboratory network with no UK presence. What you can do is get the same depth of testing, with a professional venous draw, in 103 British clinics, with a written report within 4 working days rather than four weeks.
Comparison based on Function Health's public pricing and FAQ, checked September 2026. We are one of the providers compared and have tried to be fair, including where Function is the better choice.
What Function Health is
Credit where it is due. Function Health took the idea that a healthy person should know 100 of their own numbers, not the 12 a doctor orders when something is already wrong, and turned it into a mainstream membership. For $365 a year (it was $499 until late 2025) a member gets a 100-plus biomarker panel drawn at one of 2,000-plus Quest Diagnostics sites, a mid-year retest of around 60 of those markers, a clinician-written summary, a dashboard, and paid add-on tests on top. In 2025 it bought Ezra, the full-body MRI company, and Ezra's imaging arrived in London in January 2026, which is why "Function Health UK" searches have jumped.
But the imaging is the only part that crossed the Atlantic. Function's blood testing is built on Quest, and Quest does not operate in the UK. There is no UK sign-up, no UK draw site, and no way to post a sample across the ocean. A British searcher who wants what Function offers needs a British provider that matches it on the things that matter: how many markers, how the blood is taken, how fast and how well it is explained, and what it costs.
Side by side
| Function Health (US) | TrueVitals Ultimate (UK) | TrueVitals Signature (UK) | |
|---|---|---|---|
| Available in the UK | No. Blood draws via Quest Diagnostics, US only. | Yes. 103 UK clinics, or a phlebotomist at your home. | Yes. Randox Health clinics UK and Ireland. |
| Biomarkers per draw | 100+ on the first draw; ~60 repeated mid-year ("160+ tests" across both) | 140 in one draw | 230 in one draw |
| Price | $365 a year (about £275), membership, auto-renews. Add-ons extra. | £349 one-off plus £19 clinic draw or £39 at home. No membership. | £799 all in, clinic draw included. |
| Sample | Venous draw at Quest, or at-home draw for a fee | Venous draw by a registered phlebotomist | Venous draw at a Randox clinic, physical measurements included |
| Time to full results | Results trickle in over days; complete set typically 3 to 4 weeks, then a clinician summary | Full report and dashboard within 4 working days of your blood draw | Up to 12 working days |
| The report | Dashboard with ranges plus a clinician-written summary; AI chat and "Protocols" | 30-plus page written report: every marker explained, cross-system patterns, lifestyle quiz layered in, clinician-reviewed | Same report, deeper panel |
| Retesting | One ~60 marker retest included per year, must be used before renewal | Retest whenever you choose, at the same one-off price; each new report is compared to the last | Retest whenever you choose |
| Imaging | Ezra full-body MRI, now available in the UK separately | Blood only | Blood only |
Function Health details from functionhealth.com pricing and FAQ pages as of September 2026; currency conversion approximate. TrueVitals figures are current list prices.
The markers people want
Strip away the branding and Function's appeal is a specific list: the cardiovascular, metabolic and hormonal markers that predict disease years early and that no standard check-up includes. Here is that list, and where it sits in a TrueVitals panel.
The two cardiovascular markers that outperform cholesterol. ApoB counts the particles that actually cause plaque; Lp(a) is genetic, affects one in five people, and the NHS does not test it. Both in Ultimate. Heart health blood test guide.
Insulin resistance shows here 10 to 15 years before HbA1c moves. This is the marker Function members most often cite as the one that changed their behaviour. In Ultimate. Prediabetes guide.
TSH, Free T4, Free T3 and the antibodies that catch Hashimoto's before TSH changes. In Advanced and Ultimate. Thyroid guide.
High-sensitivity CRP for the low-grade inflammation behind cardiovascular and metabolic risk. In every TrueVitals panel.
Testosterone, SHBG, oestradiol, cortisol, DHEA-S, LH, FSH, prolactin, progesterone. Ultimate carries the full set for men and women. Hormone guide.
Vitamin D, B12, folate, magnesium, full iron studies, liver enzymes, cystatin C kidney function, PSA or CA-125, immunoglobulins, and urinalysis. All in Ultimate.
Two markers Function includes that Ultimate does not: homocysteine and a handful of extended lipid sub-fractions. Both are in the Signature panel. If those specifically are why you want Function, Signature is the honest recommendation. See every biomarker by panel.
Where it differs
Function's results arrive in pieces over three to four weeks and the clinician summary comes at the end. A TrueVitals report is written once, on the complete data set, and delivered within 4 working days, so the cross-system reading (what your iron is doing to your thyroid, what your cortisol is doing to your insulin) is done on everything at once.
A dashboard shows you a number against a range. A TrueVitals report explains every marker in plain English, connects the patterns, layers in your lifestyle quiz, and is clinician-reviewed before it reaches you. See a sample report.
You pay for the test you want, when you want it. Retest whenever you choose at the same one-off price, and each new report is compared against your last so you can see exactly what has changed.
The UK equivalent
Advanced
74 biomarkers · £269
Full thyroid with antibodies, ApoB, hs-CRP, full iron studies, core hormones, liver, kidney, vitamins, HbA1c. Already more than most UK competitors' top panel.
View AdvancedClosest to Function
Ultimate
140 biomarkers · £349
Everything in Advanced plus Lp(a), fasting insulin and HOMA-IR, the complete hormone set, tumour markers, immunoglobulins, cystatin C and urinalysis. More markers than Function's first draw, in one visit, with a report within 4 working days.
View UltimateSignature
230 biomarkers · £799
Processed by Randox. Adds homocysteine, extended apolipoproteins, autoimmune, digestive and neurological screening, plus physical measurements. The deepest private panel in the UK.
View SignatureClinic draw £19 at 103 UK clinics, or £39 for a phlebotomist at your home. Klarna available. No GP referral needed.
Honest comparison
If you live in the United States, Function is excellent value and we would not try to talk you out of it: $365 for a 100-plus marker draw and a mid-year retest is cheaper per year than most UK options, and the Quest network is genuinely everywhere. If you split your time between the two countries, a US membership plus a UK Ultimate once a year is a reasonable combination. And if what you actually want is imaging, Ezra's MRI is now available in London and does something no blood test can.
For everyone in the UK who wants the blood testing, the honest position is that Function is not an option, and the choice is between British providers. Among those, the question is depth per draw, sample quality and how well the results are explained. See how every UK provider compares on exactly those.
FAQs
Not for blood testing. Function's panels are drawn through Quest Diagnostics, which operates in the United States only, and there is no UK sign-up. The imaging side of the business, Ezra, launched in London in January 2026 and offers full-body MRI in the UK separately.
The closest like-for-like is a comprehensive one-visit panel with a venous draw and a full written report. TrueVitals Ultimate tests 140 biomarkers, more than Function's first draw, for £349 one-off with a report within 4 working days. Signature tests 230 for £799. Both are available across the UK without a membership.
$365 a year as of late 2025, reduced from $499. That includes a 100-plus biomarker panel and a mid-year retest of around 60 markers, with additional tests sold as add-ons. Pricing checked September 2026.
Around 100 on the annual baseline draw, plus about 60 of the same markers repeated mid-year, which Function describes as "160+ tests". A TrueVitals Ultimate panel tests 140 distinct biomarkers in one draw; Signature tests 230.
The markers that make Function popular, ApoB, Lp(a), fasting insulin, HOMA-IR, hs-CRP, full thyroid with antibodies, complete hormones, nutrients and iron, are all in Ultimate. Homocysteine and extended lipid sub-fractions, which Function includes, are in Signature.
It depends on whether you want a fixed rhythm. Function's membership includes a partial retest each year and renews automatically. With TrueVitals you pay per test and retest whenever you choose, with each new report compared to the last. For a single baseline, a one-off Ultimate is the simpler route.
No. Function does not accept external samples and its laboratory partner is US-based. UK testing has to be done through a UK laboratory network.
74 to 230 biomarkers. Venous draw at 103 UK clinics or at home. Explained in plain English, clinician-reviewed, no membership.
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