When we think about hormones that control energy and metabolism, names like insulin, cortisol, or thyroid hormones usually come to mind. But there’s a lesser-known player with a surprising amount of influence: hepcidin. Often called the “iron hormone, hepcidin is primarily responsible for regulating iron levels in the body. However, its role goes far beyond just iron. Emerging research suggests that hepcidin also has a hand in driving fatigue, inflammation, and even weight gain.

What is hepcidin?

Hepcidin is a peptide hormone produced mainly by the liver. Its primary function is to regulate iron homeostasis. When iron levels are insufficient or too high, hepcidin levels rise, blocking the release of iron into the bloodstream from dietary sources and stored reserves. Conversely, when the body needs more iron, hepcidin levels drop, allowing more iron to circulate.

Hepcidin works by binding to a protein called ferroportin, which is responsible for exporting iron from cells. When hepcidin binds to ferroportin, it triggers its breakdown, effectively locking iron inside cells like macrophages, liver cells, and gut enterocytes.

Hepcidin and Fatigue: A Missing Link

Iron is essential for energy production because it’s a key component of haemoglobin, which transports oxygen to our tissues. If hepcidin is elevated even slightly, it can restrict iron availability, leading to symptoms that mimic iron deficiency. One of the most common is fatigue.

This mechanism is particularly relevant in chronic diseases, such as autoimmune disorders, obesity, or infections, where inflammation drives chronic elevation of hepcidin. This condition, sometimes referred to as functional iron deficiency, can leave individuals exhausted even when their iron stores appear “normal” on standard lab tests.

Inflammation: A Driver of High Hepcidin

Hepcidin is highly sensitive to inflammation. Inflammatory cytokines, especially interleukin-6 (IL-6), can trigger a sharp rise in hepcidin production. This makes sense biologically; during infection, the body tries to sequester iron to prevent bacteria from using it. However, in chronic inflammatory conditions like obesity, metabolic syndrome, and autoimmune diseases, this response becomes maladaptive.

The result? Chronically elevated hepcidin, reduced iron availability, and a persistent feeling of exhaustion and brain fog, which are often misattributed to other causes.

The Link Between Hepcidin and Fatigue

Iron is vital for the production of haemoglobin, which carries oxygen in the blood. When hepcidin levels are abnormally high, it can block iron from entering the bloodstream, even if there’s plenty of iron in the diet or stored in the body. This results in a functional iron deficiency where iron is present but unusable, leading to symptoms like fatigue, weakness, and brain fog. People with chronic inflammation, certain infections, or conditions like anaemia of chronic disease often experience elevated hepcidin and related fatigue.

How Hepcidin May Contribute to Weight Gain

Hepcidin doesn’t just affect energy levels; it may also influence metabolism and weight. Chronic inflammation, often seen in obesity, can increase hepcidin production. This creates a vicious cycle: inflammation raises hepcidin, hepcidin disrupts iron balance, low iron reduces energy and physical activity, and lower activity contributes to further weight gain. Additionally, iron is essential for proper thyroid function and metabolic rate. When iron is poorly absorbed due to high hepcidin, metabolism may slow, contributing to unwanted weight gain or difficulty losing weight.

Hepcidin, Stress, and Inflammation

Stress and chronic illness can elevate inflammatory markers like IL-6, which directly stimulates hepcidin production. This explains why people under chronic stress or dealing with long-term conditions like autoimmune diseases or infections often feel tired and gain weight despite no major changes in diet. It’s not just about willpower; the body is literally working against itself through biochemical signals like hepcidin.

Can Hepcidin Be Managed or Balanced?

Currently, there’s no direct medication to block hepcidin, though research is ongoing. However, addressing the underlying causes of inflammation, improving gut health, reducing stress, and treating infections can help lower hepcidin levels naturally. For some, managing hepcidin also means timing iron supplements strategically. For instance, taking iron during times when hepcidin is naturally lower, such as in the morning or between meals, may improve absorption.

Hepcidin may be a small hormone, but its impact is big, influencing how we feel, how much energy we have, and even our weight. Understanding hepcidin gives us a more complete picture of health, showing that fatigue and weight gain aren’t always about lifestyle choices alone. Sometimes, it’s about a hormone quietly controlling our internal iron economy and, with it, much more than we realise.


Felciya, is a Specialist Dietitian at The London Obesity & Endocrine Clinic. She has helped many patients overcome weight management barriers. ©Simplyweight


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