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Condition

Prediabetes

Elevated glucose below the diabetes threshold

Last reviewed
July 2026
Version
1.0
Review cadence
Annually

What it is

Prediabetes is blood glucose that is higher than normal but below the diabetes threshold — an HbA1c of 5.7–6.4%, a fasting glucose of 100–125 mg/dL, or an impaired glucose tolerance test. It reflects developing insulin resistance and is a warning window, not a fixed destiny.

Why it matters

Prediabetes identifies people at high risk of progressing to type 2 diabetes and its complications — but it is one of the most modifiable states in medicine. Intensive lifestyle change can cut progression substantially, often more than medication.

The evidence

What BioSignal knows about treating this

Guideline-anchored clinical contextLast reviewed July 2026 · reviewed annually · 2 references

What works for Prediabetes

BioSignal’s clinical summary, most important first.

  1. Intensive lifestyle change (the strongest evidence — diet, activity, and ~5–7% weight loss)
  2. Physical activity for insulin sensitivity
  3. Dietary carbohydrate quality
  4. Metformin in selected higher-risk people (clinician-directed)
  5. Sleep and weight management
Start Here

New to this? Read these first

  1. FoundationMetabolic HealthThe best place to understand the major drivers of metabolic disease.
  2. BiomarkerHemoglobin A1cAverage blood sugar over ~3 months
  3. Signal RecordIntermittent FastingTime-restricted eating, 5:2, and alternate-day fasting
  4. Body SystemMetabolismEnergy, blood sugar, and how the body processes fuel.
  5. ConditionType 2 DiabetesChronic high blood sugar from insulin resistance
Typical Journey

How this usually unfolds

  1. Recognize risk factors
  2. Get diagnosed
  3. Track key biomarkers
  4. Lifestyle first
  5. Evidence-based treatment
  6. Long-term monitoring

An orientation to how this topic is typically approached — not medical advice.

Who is at risk

  • Overweight and central obesity
  • Physical inactivity
  • Family history of type 2 diabetes
  • Older age
  • History of gestational diabetes or PCOS
  • Higher-risk ethnic background

How it's diagnosed

Diagnosed by HbA1c 5.7–6.4%, fasting glucose 100–125 mg/dL, or a 2-hour glucose tolerance test of 140–199 mg/dL. Fasting insulin and HOMA-IR can add context on the underlying insulin resistance.

  • HbA1c
  • Fasting plasma glucose
  • Oral glucose tolerance test
  • Fasting insulin / HOMA-IR (context)
Most important

Key biomarkers

Day to day

Lifestyle

  • Weight management
  • Regular activity
  • Carbohydrate quality
  • Sleep
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Frequently asked questions

Does prediabetes always become diabetes?

No. It signals high risk, but progression is far from inevitable — intensive lifestyle change (diet, activity, modest weight loss) substantially reduces the chance of developing diabetes, and many people return to normal glucose.

Should I take metformin for prediabetes?

Lifestyle change is first-line and, in trials, more effective. Metformin is considered for selected higher-risk people (for example, younger individuals with obesity or a history of gestational diabetes) — a clinician decision.

Evidence summary

The Diabetes Prevention Program and similar trials firmly establish that lifestyle change reduces progression from prediabetes to diabetes, outperforming metformin; the risk-marker value of prediabetes is well documented.

References & sources

  • ADA Standards of Care in Diabetes
  • Diabetes Prevention Program (DPP)

Educational information — not medical advice

Condition pages orient you across the evidence; they don't diagnose or treat. Diagnosis and management belong with a qualified clinician. See our Medical Disclaimer.

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