Always Tired? A Pharmacist’s Guide to Vitamins, B12, Iron and Energy

Always Tired? A Pharmacist’s Guide to Vitamins, B12, Iron and Energy 

By Lauren O’Reilly, Pharmacist 

Feeling tired is something most of us experience from time to time. But if you're constantly exhausted, it's tempting to reach for an “energy” supplement and hope for the best. 

My approach is slightly different: before choosing a supplement, I want to know why you're tired. 

Poor sleep, stress, lifestyle, hormonal changes, illness, medications and nutritional deficiencies can all contribute to fatigue. If tiredness has lasted for several weeks or is affecting your everyday life, it's worth speaking to your GP. Depending on your symptoms, they may recommend blood tests to look at things such as anaemia, thyroid function, diabetes or vitamin deficiencies. 

The nutrients that matter when it comes to energy 

There isn't one vitamin that gives everyone more energy. Several nutrients contribute to the processes that allow your body to release and use energy from food, while others are essential for making healthy red blood cells and supporting the nervous system. 

The ones I think are most useful to understand are iron, vitamin B12, folate and the B vitamins. 

Vitamin D is also worth considering, particularly if your levels are low. Vitamin D deficiency can be associated with muscle weakness and other symptoms that can make you feel generally run down, so it's another nutrient worth checking rather than simply assuming your tiredness is due to lack of sleep. 

B12: More than an “Energy vitamin” 

Vitamin B12 is needed for normal red blood cell formation and a healthy nervous system, and it contributes to normal energy-yielding metabolism. 

A deficiency can cause tiredness and lack of energy, but symptoms can also include pins and needles, weakness, a sore tongue, mouth ulcers and problems with memory or concentration. 

B12 deficiency is more likely in some people than others. For example, vegans may have a higher risk because B12 isn't naturally found in plant foods, so supplementation here is often recommended by healthcare professionals, where appropriate. Absorption can also be affected by conditions such as pernicious anaemia and some gastrointestinal disorders. Certain medicines, including metformin and proton pump inhibitors, can also affect B12 status. 

If you're experiencing persistent fatigue, don't assume you need a B12 supplement. A blood test can help establish whether deficiency is actually present. 

What about B-complex supplements? 

This is one area where I do sometimes recommend a B-complex, depending on the individual. 

There is some evidence that oral contraceptive use can affect the status of certain B vitamins, particularly vitamin B6. However, the evidence doesn't support the idea that modern contraceptive pills routinely cause B12 or folate deficiency. 

For women taking the oral contraceptive pill long term, I do sometimes recommend a B-complex as part of a broader nutritional approach, particularly where diet isn't great or there are other reasons to consider supplementation. 

One option we stock at Millie’s is AYA B-Complex with 1000mg Vitamin C, which provides a broad range of B vitamins alongside vitamin C. It is a high-strength formula, though, so I'd use it purposefully rather than treating B-complex supplements as something everyone needs every day. 

For women specifically looking for nutritional support alongside hormonal contraception, Health & Her Multivitamin for Women Taking Hormonal Contraception is another option worth considering. 

Iron is essential - but I wouldn't take it blindly 

Iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen around the body. When iron deficiency develops, tiredness and lack of energy are common symptoms. 

Women with heavy periods are particularly susceptible to low iron, but there are many other possible causes, including pregnancy, blood loss and low dietary intake. 

This is where I think it's really important to distinguish between a supplement for nutritional support and treatment for confirmed iron deficiency. 

If blood tests show that you are iron deficient, your doctor may recommend a higher-dose iron medicine. You shouldn't assume that a lower-dose supplement is enough simply because it's easier on the stomach. 

“Why are there so many different iron supplements?” 

This is a question I am often asked, because it can be confusing. The amount of elemental iron is what matters when comparing products - not the weight of the whole iron compound. 

And the formulation matters too. 

Traditional medicinal iron products such as Ferrograd and Galfer provide around 100 mg of elemental iron per dose. They're useful medicines for treating iron deficiency, but gastrointestinal side effects such as constipation, nausea and stomach discomfort can be an issue. Ferrograd contains 105 mg elemental iron, while Galfer contains 100 mg, and these are only sold behind the counter in a Pharmacy, following confirmation of diagnosed iron deficiency and prescribed iron supplementation. 

The important takeaway is gentler doesn't necessarily mean better — and higher dose doesn't necessarily mean better either. The right choice depends on your iron levels, why they're low, the dose you need and how well you tolerate the product. 

If your doctor has told you that you have iron deficiency anaemia, check with them or your pharmacist about the appropriate dose rather than automatically choosing the gentlest product. 

And because haemochromatosis is relatively common in Ireland, I would be particularly cautious about taking iron without knowing whether you actually need it. Haemochromatosis causes the body to absorb too much iron, allowing it to build up over time. 

Don't forget vitamin D 

Vitamin D is another nutrient I think is easy to overlook when someone says they're feeling generally run down. 

If you're deficient, correcting that deficiency is important for normal muscle function and overall health. But again, a vitamin D supplement isn't a general-purpose energy booster if your levels are already adequate. 

For someone who has been found to have low vitamin D, or who has been advised to supplement based on their individual circumstances, AYA Vitamin D3 1000IU and 2500 IU are options we stock at Millie's, depending on the dose you require. 

The key is to use the dose that's appropriate for you rather than assuming more is better. 

And what about CoQ10? 

Coenzyme Q10 is another ingredient you'll often see in “energy” supplements. 

It's involved in energy production within our cells, which is why it's included in products such as Revive Active Original. Each sachet provides 150 mg of CoQ10 alongside a broad combination of vitamins, minerals and amino acids. 

I see CoQ10 as an interesting additional ingredient in a broader supplement, rather than something I'd automatically recommend for unexplained fatigue. 

So, what vitamins should women take every day? 

There isn't a single daily supplement routine that every woman needs. 

Some people may benefit from targeted supplementation because of their diet, life stage, medication or a confirmed deficiency. Others don't need much beyond a healthy, varied diet. 

For example, folic acid is specifically recommended for women who could become pregnant, while vitamin D supplementation may be appropriate in certain circumstances. 

My preference is targeted supplementation rather than taking multiple products “just in case”. 

When tiredness needs investigating 

Speak to your GP if your tiredness: 

• has lasted for several weeks 
• is affecting your daily life 
• is getting worse 
• comes with breathlessness, palpitations or weakness 
• occurs alongside very heavy periods 
• comes with pins and needles, memory changes or other neurological symptoms 
• or simply feels unusual for you and you can't explain why. 

My Pharmacist Bottom Line 

If you're always tired, don't start with the supplement shelf - start with the reason. 

Iron and B12 deficiencies can absolutely contribute to fatigue, but taking them when you don't need them isn't the answer. 

For some women, a targeted supplement such as iron, B-complex or vitamin D may be useful. For others, the answer might be improving diet, sleep or addressing an underlying health problem. 

As Millie’s in-house pharmacist, that's why I prefer to look at your symptoms, diet, medications, life stage and, where appropriate, blood tests before deciding what supplement actually makes sense. 

A note on supplements 

If you're pregnant, have a medical condition, take regular medication or have been told you have abnormal blood results, speak to your GP or pharmacist before starting a new supplement. Iron should not be taken unnecessarily.