Why Am I So Tired All the Time? The Nutrients That Genuinely Support Energy

Feeling tired all the time is one of the most common reasons people feel below their best — and while lifestyle, sleep and stress are usually involved, nutrition is very often part of the picture. Several specific nutrient shortfalls are strongly linked to fatigue, and the reassuring news is that they are among the easiest things to check and address.

Here are the big ones, what the evidence says, and how to support your energy sensibly.

Iron — the most common culprit, especially in women

Tiredness and lack of energy are classic symptoms of iron deficiency anaemia. Iron is essential for making the red blood cells that carry oxygen around your body, so when it runs low, everything feels harder. Women are especially at risk: heavy periods and pregnancy are very common causes, and in a 2025 study of 33,000 UK adults, nearly one in three women had absolute iron deficiency — and around half of those affected reported no obvious symptoms.

The headline: in a 2025 study of 33,000 UK adults, close to 1 in 3 women were iron deficient — and about half had no symptoms they had noticed.

A crucial tip: vitamin C significantly improves absorption of the iron found in plant foods, which is why a gentle iron with built-in vitamin C, such as Zooki Iron, is a smart combination.

Vitamin B12 — energy, blood and nerves

Vitamin B12 helps turn food into energy and is essential for healthy red blood cells and a properly functioning nervous system. Deficiency causes extreme tiredness and a lack of energy, and it becomes more common with age, affecting around 1 in 10 people aged 75 or over. Vegans and vegetarians are also at higher risk, because B12 is found mainly in animal foods. A high-strength, well-absorbed option like Zooki Vitamin B12 makes topping up easy.

Magnesium — the quiet all-rounder

Magnesium is involved in hundreds of processes in the body, including energy production, and it is one of the nutrients officially recognised to contribute to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. Modern diets, stress, caffeine and alcohol all deplete it. A gentle, well-absorbed form such as Zooki Magnesium Glycinate Capsules (or the liquid Zooki Magnesium) supports energy while also helping with sleep and muscle function.

Don’t forget hydration

One of the most overlooked causes of that mid-afternoon slump is simply not drinking enough. Controlled trials show that even mild dehydration — under 2% of body weight — significantly increases fatigue and impairs concentration and mood, in both men and women. Water is the foundation, but when you are sweating, busy or flagging, an electrolyte drink helps you rehydrate and re-mineralise properly. Zooki Electrolytes+ Energy & Focus adds a smart, jitter-free energy and focus boost to its electrolytes.

The B-vitamin and mineral team

Energy metabolism is a team effort. A whole group of nutrients — vitamin C, several B-vitamins (B2, B3, B5, B6, folate and B12), plus iron and magnesium — are recognised to contribute to the reduction of tiredness and fatigue. This is exactly why a comprehensive daily multivitamin can be a sensible foundation, covering the bases if your diet is inconsistent. See Zooki Men's Multi and Zooki Women's Multi.

The bottom line

If you are tired all the time, look first at the fundamentals — sleep, stress, hydration and a nutrient-rich diet — and consider whether iron, B12 or magnesium might be low. Getting these right, in well-absorbed forms, is one of the simplest ways to feel genuinely more like yourself.

Two more energy factors: vitamin D and blood sugar

Vitamin D. Low vitamin D is common, especially through the UK winter, and is associated with tiredness and low mood. Because the sun is too weak here for much of the year, a daily Vitamin D supplement is widely recommended from around October to March.

Blood-sugar swings. That heavy, foggy feeling an hour after a sugary breakfast is a blood-sugar crash. Building meals around protein, fibre and healthy fats — rather than refined carbs alone — keeps energy steadier and avoids the peaks and troughs that leave you reaching for another coffee.

Caffeine: helpful, until it isn’t

Caffeine genuinely boosts alertness, but it borrows energy rather than creating it — and if you rely on it to paper over poor sleep or dehydration, you can end up in a cycle of jitters and crashes. Two simple rules help: keep caffeine to the first half of the day so it does not wreck your sleep, and pair it with water. Pairing caffeine with L-theanine, as in Electrolytes+ Energy & Focus, also smooths out the jittery edge for cleaner focus.

Building a day of steadier energy

• Start hydrated: you wake up mildly dehydrated, so have a glass of water before your coffee.
• Anchor meals with protein and fibre to avoid blood-sugar crashes.
• Move a little, often: a short walk beats a biscuit for a mid-afternoon lift.
• Top up the basics: if your diet is inconsistent, a daily multivitamin such as Men's Multi or Women's Multi covers the energy-supporting nutrients.

Frequently asked questions

Which single supplement is best for energy?

There is no one answer — it depends on what you are short of. Iron and B12 are the most common shortfalls behind fatigue, so those are sensible first checks.

Can I take iron and vitamin C together?

Yes — vitamin C improves iron absorption, which is why a gentle iron like Zooki Iron already includes it. Avoid taking iron alongside tea or coffee, which hinder absorption.

Should men take an iron supplement?

Usually not without reason: men and post-menopausal women rarely need extra iron and should not supplement it unless a test shows they are low. Menstruating women are the main group at risk.

Recommended products

Shop the full Zooki range, or browse the Zooki Reference Guide to match a product to your goal.