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Insulin

Insulin is a hormone produced by the pancreas, specifically by the beta cells of the islets of Langerhans. It plays a central role in glucose metabolism by regulating the amount of sugar (glucose) in the blood. Without that, the body cannot efficiently use or store glucose for energy.

Beyond its role in blood sugar control, it also influences fat storage, protein synthesis and cellular growth, making it a key regulator of metabolic health and biological aging.

How it works

After eating, especially meals rich in carbohydrates, blood glucose levels rise. In response, the pancreas secretes this hormone into the bloodstream. It binds to receptors on cells, especially in muscle, liver and fat tissue, enabling glucose to enter and be used for energy production or stored as glycogen or fat.

In summary, this hormone:

  • Lowers blood sugar by helping cells absorb glucose;
  • Promotes glycogen storage in the liver and muscles;
  • Stimulates lipogenesis (fat creation) when energy is abundant;
  • Inhibits fat breakdown (lipolysis) when their levels are high.

These actions are essential for maintaining energy balance and metabolic stability.

Insulin resistance

When cells become less responsive to its signals, a condition known as insulin resistance develops. This forces the pancreas to produce even more of this hormone to manage blood sugar, leading to hyperinsulinemia, chronically elevated levels.

Common contributors to insulin resistance include:

  • Diets high in refined carbohydrates and sugars;
  • Physical inactivity;
  • Chronic stress and elevated cortisol;
  • Poor sleep quality;
  • Visceral fat accumulation.

Over time, insulin resistance can progress to type 2 diabetes, but it may also exist silently for years, contributing to fatigue, weight gain and systemic inflammation.

Insulin and aging

Chronic elevation of insulin and poor glycemic control are associated with accelerated aging and several age related diseases. High insulin levels can:

  • Increase oxidative stress and DNA damage;
  • Promote chronic inflammation;
  • Stimulate fat storage and obesity;
  • Contribute to cardiovascular disease, cognitive decline and cancer.

In longevity research, this hormone is viewed as a key modulator of lifespan, with studies showing that lower insulin signaling is associated with extended lifespan in multiple species, from worms to rodents.

Insulin sensitivity and longevity

Insulin sensitivity refers to how effectively cells respond to this hormone. High insulin sensitivity means the body requires less of it to manage blood sugar, which is ideal for metabolic health and longevity.

People with higher insulin sensitivity tend to have:

  • Stable energy levels;
  • Better body composition;
  • Lower inflammation and oxidative stress;
  • Reduced risk of chronic diseases.

Research into blue zones and centenarian populations often reveals preserved insulin sensitivity and excellent metabolic flexibility as key traits of long lived individuals.

How to improve insulin sensitivity

Improving its sensitivity is possible with targeted lifestyle interventions:

Dietary strategies

  • Eat a low glycemic, whole food diet;
  • Emphasize fiber, polyphenols and healthy fats;
  • Avoid frequent snacking and minimize refined sugars;
  • Incorporate apple cider vinegar or cinnamon with meals.

Physical activity

  • Strength training improves glucose uptake in muscle;
  • Walking after meals reduces post-meal glucose spikes;
  • HIIT and aerobic exercise both increase their sensitivity.

Fasting practices

  • Time restricted eating lowers their levels and enhances sensitivity;
  • Intermittent fasting promotes metabolic flexibility and fat adaptation.

Sleep and stress

  • Prioritize 7–9 hours of quality sleep;
  • Practice stress management techniques (breathwork, meditation, nature walks);
  • Manage cortisol levels to reduce their resistance.

Supplements that may help

  • Berberine: mimics the effects of metformin;
  • Magnesium: improves insulin signaling;
  • Alpha-lipoic acid (ALA): antioxidant support for glucose uptake;
  • Chromium: may enhance insulin action;
  • Ceylon cinnamon: may reduce fasting glucose and improve sensitivity.

Insulin is much more than a blood sugar hormone, it’s a central regulator of energy, metabolism, fat storage and aging. While essential for life, too much of it, too often, accelerates biological aging and chronic disease.

By supporting its sensitivity through diet, movement, stress reduction and strategic fasting, we can promote better metabolic health and potentially extend both lifespan and healthspan.

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