Hair Test vs Blood Test vs Elimination Diet

This page compares the four routes people in the UK actually use when they suspect a food is not agreeing with them: a hair sample screen like ours, an IgG blood test, a plain elimination diet, and testing through the NHS. For each one it sets out what is being measured, the typical cost, how long it takes, how strong the evidence behind it is, and what it is honestly useful for. The short version, stated at the top so you can stop reading if that is all you came for: an elimination diet is the only one of the four that can actually demonstrate a link between a food and how you feel. Every other method on this page, including the screen we sell, only narrows down where to start.

What this screen is — and what it is not

Before comparing anything, it is worth being blunt about our own product, because the rest of the page only makes sense once you know where we stand.

What our hair sample screen is:

A non-medical screening of 9-10 strands of hair, processed at a UK lab, covering 700+ items on the Gold screen (350 foods and drinks plus 350 non-food items).
A shortlist. It returns items your sample reacted to, so you have somewhere specific to begin instead of guessing from a list of everything you eat.
A way to structure a six-week elimination and reintroduction that you run yourself.
Quick and low-effort: no needles, no kit to wait for, no appointment. You post the strands yourself and your report is emailed within 3 working days of the sample arriving at the lab.
Backed by a 90-day money-back guarantee, on stated conditions: follow the plan for 6 weeks and keep a food diary.

What it is not:

A diagnostic test. It does not diagnose, treat or prevent anything, and it is not read or interpreted by a clinician.
A validated method. Hair screening of this kind has no proven accuracy, no peer-reviewed evidence base, and no approval from the MHRA or FDA as a medical test. The report on its own proves nothing about your body.
An allergy test. It does not measure IgE antibodies and must never be used to rule an allergy in or out.
A test for coeliac disease, lactose intolerance or any other named medical condition. Those are things to raise with your GP, who can arrange the proper blood work.
Proof of anything you notice afterwards. If you feel better during an elimination, the credit belongs to the elimination, not to the screen that suggested where to look.

We have been trading since 2017 and have completed 250,000+ screens, and our Google rating is 4.3 from 44 reviews. That tells you people find the service useful and that we have been around a while. It is not evidence that the method is accurate, and we will not present it as such.

The four routes compared

Method	What it measures	Typical UK cost	Turnaround	Evidence base	Best for
Elimination diet and food diary	Your own response to removing and then reintroducing a specific food	Nothing beyond your normal food bill	6 weeks of removal, then several days per food reintroduced	Strongest of the four. The approach dietitians generally favour, because it observes the thing you actually care about	Anyone willing to put in the weeks. It is the only method that demonstrates a link
Hair sample screen (what we sell)	A proprietary lab screen of a hair sample, reported as items your sample reacted to	£37 Silver (top 100 items), £49 Gold (700+ items), £65 Platinum	3 working days from the sample arriving; allow 5-7 days from posting	No proven accuracy. No published evidence that it identifies foods that affect you	People who want a starting shortlist and a structure, and who accept it proves nothing on its own
IgG blood test	Levels of IgG antibodies to a panel of food proteins	Roughly £130-£240	Commonly one to two weeks after the sample reaches the lab	Contested. Allergy bodies advise against using IgG to identify food intolerance; the NHS does not generally offer it	People who specifically want a blood-based panel and understand the disagreement about what it means
NHS testing	IgE allergy testing (skin-prick or blood) and coeliac screening (blood serology, sometimes biopsy)	Free at the point of use	Depends on referral and local waiting times	Established clinical testing, but aimed at allergy and coeliac disease, not at food intolerance	Anyone with worrying symptoms, a suspected allergy, or a reason to rule out a medical cause. Always the first stop

The elimination diet: the only method that demonstrates a link

Everything else on this list produces a piece of paper. Only an elimination diet produces a cause-and-effect observation about you.

The logic is simple. You remove a small number of suspected foods for around six weeks and record what you eat and how you feel each day. Once things have settled, you bring foods back one at a time, leaving several days between each, and watch what happens. If a food reliably brings a change back and removing it makes the change go away, you have something worth acting on. No laboratory reading can substitute for that, because no laboratory is measuring your day.

The honest drawbacks are real. It takes discipline and label reading. Your diary has to be accurate, because memory quietly rewrites itself. It is slow, and it is not perfectly clean: if you also start sleeping better, drinking less or feeling less stressed during the same six weeks, you may not know which change did the work. Expectation can colour your judgement too. Structured reintroduction is the part that controls for most of this, which is why it matters more than the removal phase and why so many people skip it and end up no wiser.

Its biggest practical problem is not accuracy but where to point it. A typical adult diet contains hundreds of ingredients. Removing everything is unsafe and unsustainable, so you need a shortlist. Working out that shortlist is the only job any test on this page can genuinely do for you.

IgG blood testing: what you are actually buying

An IgG blood test measures antibodies your immune system produces in response to food proteins, across a panel of foods, and returns a list with numbers against each one. Prices in the UK run roughly £130-£240.

The disagreement is not about whether the antibodies are there. They are, and the labs measure them. The disagreement is about what a raised reading means. Everyone produces IgG to foods they eat, whether or not the food bothers them. IgG is a marker of exposure to a food protein, and it can appear in people who tolerate that food perfectly well. Professional allergy organisations have repeatedly advised against using IgG panels to identify food intolerance, and the NHS does not routinely offer them for that purpose.

People do sometimes report feeling better after cutting out their high-IgG foods. That is worth taking seriously, but the most likely explanation is the same one that applies to our screen: they carefully removed foods and paid attention. The removal did the work. The panel just chose the foods.

Hair sample screening: where we sit, stated plainly

Our screen is cheaper than an IgG panel, needs no needles and no appointment, and covers a far wider list of items. Those are genuine practical advantages, and they are the only advantages we will claim.

On evidence, our position is worse than IgG testing, not better. IgG testing at least measures a real biological molecule whose meaning is disputed. Hair is largely non-living keratin and carries no circulating immune markers at all. There is no robust published research showing that screening a hair sample can identify which foods affect a person, and repeat samples do not always agree. We are not going to dress that up.

So what is the product for? It is for turning “it could be anything I eat” into “start with these”. If you were going to attempt an elimination diet anyway and could not decide what to remove, a £49 shortlist across 700+ items is a cheap way to stop dithering and start observing. The value sits entirely in what you do next. If you take the report, never change your diet and treat the list as a set of facts about your body, you have wasted your money and we would rather say so before you spend it.

NHS testing: free, but aimed at something else

The NHS does test food-related problems, and it does it properly. What it tests for is allergy and coeliac disease, both of which are medical conditions with defined diagnostic pathways: IgE testing by skin-prick or blood for suspected allergy, and blood serology with a possible biopsy for suspected coeliac disease. There is no NHS test for food intolerance, because there is no validated laboratory test for it anywhere. NHS and dietetic guidance for suspected intolerance points at a supervised elimination diet.

This is why a private test is never a substitute for a GP appointment. Our screen does not test for coeliac disease and does not test for allergy, and it cannot rule either out. If your symptoms are severe, persistent, or accompanied by anything that worries you, that is a GP conversation first, and any food experiment comes afterwards.

Does this sound like you?

A hair sample screen may be a reasonable purchase if most of these are true:

You have already seen your GP, or your symptoms are mild and long-standing rather than new, severe or escalating.
You genuinely intend to change what you eat for six weeks and keep a written diary, not just read a report.
You cannot work out where to start, and the list of candidate foods feels impossibly long.
You are comfortable with the idea that the report is a suggestion to test, not a finding to act on permanently.
£37-£65 is money you can spend on a starting point without resenting it if nothing comes of it.

It is probably not for you if any of these apply:

You have had a sudden, severe reaction to a food, or any swelling, difficulty breathing or collapse. That is an allergy question and belongs with a doctor, urgently.
You want proof, or a diagnosis, or something to show a clinician. This is not that document.
You are pregnant or breastfeeding, in which case the screen is not suitable and dietary changes should be led by your midwife or GP.
You are testing for a child under 6, which we do not accept.
You have a history of disordered eating, where restricting foods can do real harm. Speak to a professional first.

How to run a focused six-week elimination

This is the part that does the work, whichever method gave you your shortlist, and it is what our 90-day money-back guarantee asks you to complete.

Before you start

Pick a shortlist of no more than three or four items, whether from a report or from your own suspicions. Removing twenty foods at once is unsustainable and tells you nothing.
Start the diary on day one, before you change anything, so you have a baseline. Record meals, timings, and a simple score out of ten for how you felt, with a note on sleep, stress and anything else unusual.
Plan replacements before you remove anything. An elimination that leaves you hungry or short of a food group will not last six weeks, and cutting out a whole group needs proper advice.

Weeks one to six

Remove the shortlisted items completely, including in sauces, sandwiches and drinks. Partial removal produces an uninterpretable result.
Change nothing else deliberately. If you overhaul your sleep and alcohol at the same time, you will not know what caused any improvement.
Expect the first week or two to be uninformative. Give the full six weeks before drawing conclusions.

Structured reintroduction

Reintroduce one item at a time, in a normal portion, keeping everything else unchanged.
Wait three to five days before the next item. Reactions to foods can be delayed by hours or longer, and this gap is what lets you attribute anything you notice to a specific food.
Record the result before moving on. If nothing happens, that food goes back into your diet permanently. That is a useful result, not a failure.
If something does happen, remove that item again, wait for things to settle, and reintroduce it once more. A pattern that repeats twice is worth acting on. A one-off is not.
At the end, you should have a short list of items you have personally tested, and a much longer list you have cleared. Most people finish with fewer restrictions than they feared.

Common questions

If the elimination diet is the only method that proves anything, why buy a test at all?

Because the elimination diet needs a starting point and most people cannot choose one. That is the whole job of the screen: it gives you a small number of items worth exploring first instead of a blank page. If you already have a strong suspicion about a specific food, skip the test and go straight to the six weeks. That advice costs you nothing and works better than anything we can sell you.

Is an IgG blood test more reliable than a hair sample screen?

It measures a real molecule, which a hair screen does not, so in that narrow sense it is measuring something. But the meaning of the reading is disputed by allergy specialists, and the NHS does not generally offer it for intolerance. Neither method can tell you that a food affects you. Both, at best, produce a shortlist to test.

Can this tell me whether I have coeliac disease?

No. Our screen does not test for coeliac disease and cannot rule it out. Coeliac screening is a specific blood test arranged by your GP, and it needs you to still be eating gluten at the time, which is exactly why you should ask about it before starting any elimination. If coeliac disease is a possibility, see your GP first.

How long does the whole process take?

Allow 5-7 days from posting your sample to receiving your report, since your report is produced within 3 working days of the sample arriving and the post is the variable. Then allow six weeks of removal and a few weeks of reintroduction. Realistically you are looking at two to three months before you have an answer you can trust, and the delay is in the elimination, not the lab.

Can I test more than one person at once?

Yes. There is a Couples option at £74 and a Family option at £125, and a Personalised Meal Plan add-on at £10 if you would rather not build the six weeks of meals yourself. Everyone tested must be aged 6 or over.

What does the money-back guarantee actually cover?

If you follow your plan for six weeks and keep a food diary, and you are no better off, you can claim a full refund within 90 days. The conditions exist because the elimination is where any change comes from. We keep your data for 6 months, after which no records are held.

What if my report flags something I eat every day and love?

Then it is a candidate to test, nothing more. Remove it for the six weeks, reintroduce it carefully, and let your own response decide. Plenty of flagged items turn out to be perfectly fine, and finding that out is a legitimate use of the process.

When to speak to your GP. This hair sample screen is a non-medical, educational wellness service. It does not diagnose, treat or prevent any condition, it is not an allergy test, it does not test for coeliac disease, and it is not a validated method. If you have persistent or severe symptoms, unexplained weight loss, blood in your stool, difficulty swallowing, or any symptom that worries you, please see your GP before doing anything else. Talk to your GP, dietitian, midwife or pharmacist before making significant dietary changes, particularly if you are breastfeeding, taking medication or managing an existing condition. The screen is not suitable during pregnancy, and is for ages 6 and over.