Insulin
| Clinical | Optimal | |
|---|---|---|
| Male | 18 - 173 pmol/L | Below 60 pmol/L (ideal below 40 pmol/L) |
| Female | 18 - 173 pmol/L | Below 60 pmol/L (ideal below 40 pmol/L) |
What is Insulin?
Insulin is a hormone produced by the beta cells of your pancreas. Its primary role is to regulate blood sugar by signalling your cells to absorb glucose from the bloodstream for energy or storage. Measuring fasting insulin tells you how much of this hormone your pancreas needs to produce to keep your blood sugar at a normal level overnight.
In a healthy metabolic state, only a small amount of insulin is needed to maintain stable blood sugar. However, when cells become resistant to insulin's effects (insulin resistance), the pancreas must produce progressively more insulin to achieve the same result. This means fasting insulin levels can be elevated long before blood sugar itself begins to rise.
This makes fasting insulin one of the earliest detectable markers of metabolic dysfunction. It can reveal insulin resistance years, sometimes even a decade, before fasting glucose or HbA1c enter abnormal ranges. It is a marker that longevity researchers consider essential for comprehensive metabolic assessment.
Why Insulin Matters for Your Health
Insulin resistance is now recognised as a central driver of many of the most common chronic diseases, including type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, polycystic ovary syndrome (PCOS), and certain cancers. It is also strongly implicated in accelerated biological ageing.
From a longevity perspective, keeping insulin levels low is one of the most powerful metabolic goals. Chronically elevated insulin promotes fat storage (particularly visceral fat), inflammation, and cellular growth signals that may accelerate ageing processes. Many of the metabolic benefits associated with caloric restriction and fasting are mediated through reduced insulin signalling.
Fasting insulin is the earliest canary in the metabolic coal mine. By the time fasting glucose or HbA1c become abnormal, insulin resistance has often been present for years. Testing fasting insulin allows you to detect and reverse this trajectory at the earliest possible stage, when dietary and lifestyle interventions are most effective.
Insulin& Your Wearable Data
Fasting insulin is one of the earliest markers of developing insulin resistance and metabolic dysfunction, often rising years before glucose levels become abnormal. Wearable activity data is highly relevant: regular physical activity improves insulin sensitivity directly. Your wearable's tracking of daily steps, active minutes, and exercise sessions all correlate with lower fasting insulin concentrations.
The timing and intensity of exercise matter for insulin sensitivity. Wearable heart rate zone data can help you optimise your training: both moderate continuous exercise (zone 2-3) and high-intensity intervals (zone 4-5) improve insulin sensitivity, but through different mechanisms. Tracking your weekly distribution across heart rate zones helps ensure you are getting the right mix for metabolic health.
Sleep deprivation is a potent driver of insulin resistance. Wearable sleep data showing consistently short sleep duration, fragmented sleep, or reduced slow-wave sleep is associated with elevated fasting insulin. Even partial sleep restriction of 1-2 hours per night for a week can reduce insulin sensitivity by 25%. Your wearable sleep trends provide actionable data for protecting metabolic health.
What High Insulin May Suggest
Elevated fasting insulin is the hallmark of insulin resistance. It indicates that your pancreas is working overtime to produce extra insulin to keep blood sugar within normal limits. While blood sugar may still appear normal, the metabolic machinery behind the scenes is under significant strain.
Common causes include excess body weight (particularly visceral fat), a diet high in refined carbohydrates and sugars, physical inactivity, chronic stress, poor sleep quality, and genetic predisposition. Insulin resistance is strongly associated with metabolic syndrome, a cluster of conditions that dramatically increases cardiovascular risk.
High insulin promotes fat storage, suppresses fat burning, increases inflammation, and drives excessive cellular growth. Over time, the pancreas may become unable to keep up with the demand, leading to rising blood sugar and eventually type 2 diabetes. Addressing elevated insulin early through lifestyle changes can halt and reverse this progression.
What Low Insulin May Suggest
Low fasting insulin generally indicates good insulin sensitivity, meaning your cells respond efficiently to insulin and only a small amount is needed to maintain healthy blood sugar levels. This is typically a favourable finding.
Very low insulin (below 15 pmol/L) combined with elevated blood sugar may suggest inadequate insulin production, which could indicate type 1 diabetes or latent autoimmune diabetes in adults (LADA). This pattern requires prompt medical evaluation.
In the absence of elevated blood sugar, low fasting insulin reflects excellent metabolic health and is associated with reduced risk of chronic disease and healthy ageing.
How to Optimise Your Insulin
Food
Dramatically reduce refined carbohydrates and added sugars, which are the primary dietary drivers of insulin spikes, Increase intake of non-starchy vegetables, which provide fibre and nutrients without significantly raising insulin, Choose protein sources that do not spike insulin excessively, such as fish, eggs, and plant-based proteins, Include healthy fats from avocados, olive oil, and nuts, which improve satiety without raising insulin, Consider reducing meal frequency where appropriate, as each eating occasion triggers an insulin response
Lifestyle
Prioritise resistance training and high-intensity exercise, which are the most effective exercise types for improving insulin sensitivity, Aim for 7-9 hours of quality sleep, as sleep deprivation rapidly increases insulin resistance, Manage chronic stress, as cortisol directly impairs insulin sensitivity and promotes visceral fat storage, Consider time-restricted eating, consuming all meals within an 8-10 hour window, to provide longer daily periods of low insulin, Reduce sedentary behaviour by taking regular movement breaks throughout the day
Supplements
Berberine (500mg two to three times daily) is well-evidenced for improving insulin sensitivity and reducing fasting insulin levels, Magnesium (300-400mg daily as glycinate) is commonly deficient and directly involved in insulin signalling pathways, Chromium picolinate (200-1000mcg daily) may help enhance insulin receptor sensitivity
When to Speak to Your GP
Consult your GP if your fasting insulin results suggest levels significantly above the reference range, particularly if combined with elevated fasting glucose, HbA1c in the pre-diabetic range, or symptoms such as difficulty losing weight, fatigue after meals, or skin darkening (acanthosis nigricans). Seek medical advice if insulin is very low alongside elevated blood sugar, as this pattern may suggest a different type of diabetes requiring specific treatment.
References
- NICE. Type 2 diabetes in adults: management. NICE guideline NG28. nice.org.uk
- NHS. Type 2 diabetes — Understanding medicine. Updated 2024. nhs.uk
- NEJM. Reaven GM. Role of insulin resistance in human disease. Diabetes. 1988;37(12):1595-1607. pubmed.ncbi.nlm.nih.gov
- Lancet. Tabak AG, et al. Prediabetes: a high-risk state for diabetes development. Lancet. 2012;379(9833):2279-2290. pubmed.ncbi.nlm.nih.gov
Medical Disclaimer— This content is for general educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Omniwo Ltd is a wellness information service and is not a medical device, clinical laboratory, or regulated healthcare provider under MHRA guidelines. The “optimal ranges” presented on this page are based on published clinical guidelines (WHO, NICE, NHS) and peer-reviewed research; they represent functional wellness targets and may differ from standard laboratory reference ranges. Individual results should always be interpreted by a qualified healthcare professional (such as your GP) who understands your full medical history. Do not start, stop, or change any medication or supplement based solely on this information. If you are experiencing symptoms, seek medical attention promptly.