Health condition · Clinically reviewed
Pre-diabetes, a reversible risk state, if you catch it.
HbA1c of 42-47 mmol/mol — above normal but below diabetes. A clear window for evidence-based lifestyle change to prevent progression.
Why trust this guide
- 01
Clinically reviewed
Written by our editorial team and reviewed by a registered UK clinician before publication.
- 02
Sourced from guidance
Every claim is checked against NICE, Diabetes UK or peer-reviewed sources you can see at the end.
- 03
Current for 2026
Reflects current UK guidance on the NHS Diabetes Prevention Programme, weight loss targets and where GLP-1s fit.
Key facts
Pre-diabetes at a glance.
The essentials, in plain English - what it means, how common it is, and why acting now genuinely changes the trajectory.
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What it is
A reversible risk state defined by HbA1c 42-47 mmol/mol - above normal, but below the diabetes threshold.
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How common
Around 1 in 3 UK adults over 40 have pre-diabetes - many without knowing.
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Progression risk
Without action, roughly 5-10% of people with pre-diabetes progress to type 2 diabetes each year.
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The NHS DPP works
The NHS Diabetes Prevention Programme cuts the risk of progression substantially in people who complete it.
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Weight is the biggest lever
A 5-10% body weight loss dramatically reduces the chance of progressing to type 2 diabetes.
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It is silent
Pre-diabetes has no symptoms - which is why risk-based HbA1c screening is essential.
Why this guide matters
A warning, not a verdict.
Pre-diabetes is one of the few labels in medicine where action reliably rewrites the story. The three points below shape everything else on this page.
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Reversal is realistic
A 5-10% weight loss with a Mediterranean-style diet moves many people back to normal HbA1c.
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The NHS DPP works
Nine months of structured support cuts progression risk substantially in people who complete it.
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Cardiovascular risk starts now
Pre-diabetes already raises heart and stroke risk - BP, lipids and QRISK3 belong in the same visit.
How the diagnosis is made
From screening HbA1c to a prevention plan.
The steps a UK GP will normally follow, in order - so you know what to expect and why.
Phase 1 · Recognising
Screening and diagnostic tests
Phase 2 · Confirming
Baseline work-up and cardiovascular risk
Phase 3 · Managing
Referral to a prevention programme
- 01
Recognising
Screening HbA1c
A single blood test measuring average glucose over 3 months - offered on risk factors or NHS Health Check.
- 02
Recognising
Repeat if borderline
A single borderline HbA1c is often repeated within 3-6 months to confirm the trend.
- 03
Recognising
Fasting glucose or OGTT
If HbA1c is uncertain or unreliable (e.g. anaemia, haemoglobin variants), a fasting glucose or oral glucose tolerance test is used.
- 04
Confirming
Lipid profile
Cholesterol and triglycerides - because pre-diabetes rarely travels alone.
- 05
Confirming
Blood pressure measurement
BP is checked at the same visit - hypertension often co-exists and multiplies cardiovascular risk.
- 06
Confirming
QRISK3 cardiovascular assessment
A 10-year heart and stroke risk estimate - guides whether a statin is offered alongside lifestyle change.
- 07
Managing
Referral to a structured programme
NHS Diabetes Prevention Programme or a private equivalent - the intervention with the strongest evidence.
Typical timeline: 4-8 weeks from first HbA1c to a settled plan.
Signs & risk factors
What pre-diabetes actually looks like.
Usually, nothing at all - which is why risk factors matter. Here is what puts you in a higher-risk group and when to seek urgent care.
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Asymptomatic (typical)
Most people with pre-diabetes feel entirely well - which is why it is found on screening, not symptoms.
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Central weight gain
Weight around the middle is the pattern most strongly linked to insulin resistance and pre-diabetes.
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Obesity
A BMI over 30 (or over 27.5 in South Asian and other high-risk groups) sharply raises the risk.
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Family history of T2DM
A parent, sibling or child with type 2 diabetes puts you in a higher-risk screening group.
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Prior gestational diabetes
A history of diabetes in pregnancy needs lifelong annual HbA1c screening.
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PCOS
Polycystic ovary syndrome is closely linked to insulin resistance - screening is recommended.
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South Asian, African-Caribbean ethnicity
These groups develop pre-diabetes at a lower BMI and younger age - screening starts earlier.
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Red flag: symptomatic diabetes
Thirst, polyuria, unexplained weight loss - repeat HbA1c urgently; this is no longer pre-diabetes.
Treatment
How pre-diabetes is managed in the UK.
Structured lifestyle change first - with medication reserved for higher-risk cases. Here is what each option does, and where it fits.
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NHS Diabetes Prevention Programme
A free 9-month structured behavioural programme - the intervention with the strongest evidence base in the UK.
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Structured lifestyle programme
Private equivalents run by dietitians and health coaches - useful if NHS DPP is not available or accessible.
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Mediterranean-style diet
Higher fibre, olive oil, oily fish, vegetables and legumes - the most consistently supported eating pattern.
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150 min/week + resistance
150 minutes moderate activity per week plus 2 resistance sessions - protects muscle and insulin sensitivity.
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5-10% weight loss target
A modest, sustained weight loss of 5-10% is the single most powerful lever against progression.
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Metformin (specific cases)
Considered in higher-risk pre-diabetes where lifestyle change alone has not worked - a specialist or GP decision.
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GLP-1 for higher-risk BMI
Semaglutide or tirzepatide - considered in specialist settings for higher-BMI, higher-risk pre-diabetes.
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Annual HbA1c surveillance
Yearly HbA1c to catch progression early - or to confirm you have moved back to a normal range.
What this guide is based on
The sources behind every number on this page.
UK national guidance and specialist society standards, current at the time of last review.
Key references
Guidelines and standards we relied on.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, ask them.
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NICE. Type 2 diabetes: prevention in people at high risk (PH38 / NG38).
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Diabetes UK. Patient information on pre-diabetes.
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NHS. NHS Diabetes Prevention Programme.
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Diabetes Prevention Program (DPP) research group. Long-term follow-up studies.
Red flags
When pre-diabetes needs more than lifestyle change.
Most pre-diabetes is a slow, silent process. These are the situations where a prevention programme alone is not enough.
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Symptomatic diabetes on presentation
Thirst, polyuria, tiredness - repeat HbA1c urgently; this is no longer pre-diabetes.
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Rapid weight loss
Unexplained weight loss with high glucose - deserves same-day assessment.
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Very high HbA1c (>48 mmol/mol)
Above the diabetes threshold - triggers full diabetes work-up, not a prevention programme.
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Ketones on urine dip
Any positive urine ketones with hyperglycaemia - urgent assessment for possible new type 1 or DKA.
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Family history of MODY
Young-onset diabetes across generations - consider specialist referral for genetic testing.
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Post-transplant
Immunosuppression can trigger new-onset diabetes - specialist-led monitoring is needed.
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Pregnancy planning
Aim to normalise HbA1c before conception - discuss with your GP or diabetes team.
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PCOS with severe symptoms
Severe insulin resistance may need specialist endocrinology input alongside lifestyle change.
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Post-bariatric surgery follow-up
A recurrence of pre-diabetes after bariatric surgery warrants specialist review.
Living with it
A window to change the story, if you use it.
Four things that make the biggest difference day to day - food, activity, reviews and mindset.
A quiet reminder
Consistency beats intensity, every time.
Small, steady changes - kept up for months - do more than a heroic week that does not last.
- 01 Food
Not what you cut - what you add
Building meals around vegetables, protein and fibre changes the whole day. Less about strict restriction.
- 02 Activity
Move after meals
Even a 10-minute walk after eating meaningfully reduces post-meal glucose peaks.
- 03 Reviews
Annual HbA1c matters
A yearly HbA1c catches progression early - or confirms your changes are working.
- 04 Mental health
A diagnosis is not a failure
Pre-diabetes is a warning, not a verdict. Ask for support if the label is weighing on you.
Frequently asked
Everything we get asked about pre-diabetes.
Quick answers on HbA1c, reversal, the NHS DPP, metformin, GLP-1s and when to worry.
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What is pre-diabetes?
A reversible risk state where HbA1c sits at 42-47 mmol/mol - above normal, but below the diabetes threshold of 48. It signals a clear window to act before type 2 diabetes develops.
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How is pre-diabetes diagnosed?
By a blood test - usually HbA1c between 42 and 47 mmol/mol. A fasting glucose or oral glucose tolerance test is used when HbA1c is unreliable.
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Can pre-diabetes be reversed?
Yes - a sustained 5-10% weight loss combined with a Mediterranean-style diet and regular activity moves many people back to a normal HbA1c range.
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What is the NHS Diabetes Prevention Programme?
A free 9-month structured behavioural programme for adults at high risk of type 2 diabetes - the intervention with the strongest UK evidence base for preventing progression.
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Should I take metformin for pre-diabetes?
Not routinely. Metformin is considered in higher-risk pre-diabetes where lifestyle change alone has not worked - a decision made with your GP or a specialist.
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Do GLP-1 injections like semaglutide have a role?
In specialist settings, for higher-BMI, higher-risk pre-diabetes - GLP-1s can support meaningful weight loss and reduce progression. Not a first-line option for most.
Related content
Keep reading.
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HbA1c diabetes test
The blood test at the heart of the diagnosis.
Learn more -
Lipid profile
Cholesterol testing - because risk rarely travels alone.
Learn more -
Cardiovascular risk assessment
QRISK3 and what to do with the number.
Learn more -
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