Do Multivitamins Actually Work? What the Evidence Really Says

Walk down any pharmacy or supermarket aisle, and you will see shelves full of multivitamins promising better energy, stronger immunity, and a healthier you. In the UK alone, we spend over £500 million a year on vitamins and supplements. Around three in four adults take something, whether that is a daily multivitamin, vitamin D, or omega-3 capsules.

It is natural to want something simple you can do to look after your health. For many of us, swallowing a tablet every morning provides a certain peace of mind. Perhaps your mum always gave you vitamins as a child. Perhaps you saw an advert that made you worry you were missing something, or perhaps you just like the feeling of doing something proactive.

But do these tablets actually do anything? It depends on who you are and what you are hoping to achieve.

Will a multivitamin help you live longer?

A major study published in 2024 looked at nearly 400,000 healthy adults in the US. Researchers followed them for over 20 years. The findings were clear: people who took daily multivitamins did not have a lower risk of dying from any cause than people who did not take them. There was no difference in deaths from cancer, heart disease, or stroke.

This is not one small study. It is one of the largest and longest investigations into multivitamin use ever undertaken. And it matches what other big reviews have found. For most healthy adults who eat a reasonable diet, a daily multivitamin does not seem to add extra years to their lives.

If you have been taking them in the hope of protecting yourself from serious illness, this might feel disappointing. Take reassurance in that the same research found no harm either. You have not been doing anything wrong.

For most people, this finding simply confirms that you are probably already getting what you need from your food.

So are they completely useless?

You might think so after reading the above. But there is more to the story.

While multivitamins do not seem to help us live longer, there is some evidence that they might help our brains work a little better as we age. A well-designed study called COSMOS followed over 5,000 older adults for two years. People who took a daily multivitamin had better memory and slightly slower mental decline compared to those who took a placebo (dummy pill).

The effect was small, and multivitamins are certainly not a cure for dementia. But it suggests that for older adults, there may be specific benefits worth considering.

It is best to see a multivitamin as a way to fine-tune your health rather than a way to stop a major illness. They will not stop a heart attack or stroke. But they can provide a small safety net and help fill in the gaps on days when your meals are not as varied or healthy as you would like them to be.

Who genuinely needs a supplement?

While most “healthy” people do not need a general multivitamin, some people have genuine nutritional gaps that food alone cannot easily fill. For these groups, supplements are not a luxury but a real necessity.

Vitamin D is the big one in the UK. From October to March, the sun (what sun, you might be asking!) is not strong enough for our skin to make enough of it. The NHS recommends that everyone consider taking 10 micrograms of Vitamin D daily during autumn and winter. Some people need it all year round, including those who do not get outside much, people with darker skin, and those who cover most of their bodies for religious or cultural reasons.

Women who are pregnant or trying to conceive should take 400 micrograms of folic acid every day until they are 12 weeks pregnant. This helps prevent serious problems with the baby's spine and brain development. Start taking it before you stop using contraception if pregnancy is a possibility. This is one supplement where the evidence for its use is rock solid.

People following a vegan diet often need vitamin B12. This vitamin is not found naturally in plants, and without it, you can develop a type of deep tiredness that does not improve with rest, along with nerve problems that can become permanent if left untreated.

Children aged six months to five years should be given daily vitamins containing A, C, and D, unless they are drinking more than 500ml of formula a day. Breastfed babies should get vitamin D drops from birth.

And if you have a medical condition that affects how you absorb nutrients, such as Crohn's disease, coeliac disease, or if you have had weight loss surgery, you will likely need specific supplements for life. Your body simply cannot extract what it needs from food in the usual way. A dietitian or specialist should guide you with exactly what you need.

If you fall into any of these groups, a supplement is not a waste of money. It is doing a real job.

Getting the most from your multivitamins

Taking the right supplement is only half the story. If it is taken in a way that prevents proper absorption, the benefit is lost. A few practical points can make a real difference.

Many vitamins in a multivitamin formula, including A, D, E, and K, are fat-soluble. This means your body cannot absorb them properly without a small amount of fat. Taking them on an empty stomach with just water means they will pass straight through without bringing you any benefit. A meal containing some fat, even just a splash of milk in your tea or a few nuts, helps your body to actually use what you have paid good money for.

Timing matters too. B vitamins help the body turn food into energy, and for some people, they can be mildly stimulating. Taking a multivitamin late in the day can occasionally cause restless sleep or vivid dreams. Breakfast or lunch is usually the better choice.

If you are already taking individual supplements like vitamin D or iron, check whether your multivitamin also contains them. Doubling up is easy to do by accident, and certain vitamins can cause problems if they build up over time. Vitamin A, for example, is stored in the liver and can reach harmful levels if you take more than the recommended amount for prolonged periods. Iron can cause stomach problems and, in excess, more serious issues. More is not always better.

A word on safety

Multivitamins are generally safe for most people at standard doses. But there are situations where caution is needed.

If you take blood thinners like warfarin, vitamin K in multivitamins can interfere with how the medicine works and can increase the risk of a blood clot developing. If you have kidney problems, certain minerals can build up to dangerous levels because your body cannot clear them properly. If you are pregnant, high doses of vitamin A can harm your baby, which is why pregnancy-specific supplements exist.

If you are on regular medication or have a long-term health condition, check with your pharmacist or GP before starting a new supplement. This is not about being overly cautious. It is about making sure everything works together safely.

Here is a summary of some common vitamins that you may need to avoid or use with caution if you have certain health conditions:

The real issue with the UK diet

Many people in the UK are simply not getting enough vitamins and minerals from their food in the first place.

Government surveys show that teenage girls are especially at risk of low iron. Nearly one in five adults has vitamin D levels below the recommended threshold. Only about one in six of us manages to eat five portions of fruit and vegetables a day.

This happens for understandable reasons. Life is busy. Healthy food can feel expensive or time-consuming. Processed snacks are designed to be tasty and addictive. And when you are tired, a ready meal or takeaway is always going to win over chopping vegetables.

A multivitamin can help fill some of those gaps. But it cannot replicate what whole food provides. Real food contains fibre, antioxidants, and hundreds of compounds that work together in ways a tablet cannot mimic. Supplements are a backup, not a replacement.

Food first approach

Life is busy, and eating a perfect diet every day can be hard. However, it is worth remembering that a pill can never quite replace the goodness we get from real food.

A varied diet is your most powerful tool. Simple changes can make a big difference to how you feel. For example, you could try to add one extra portion of fruit or vegetables to your plate each day. Whole grains and healthy proteins also help your body get the vitamins it needs naturally.

Think of vitamins as a small helping hand rather than a total fix. When we focus on healthy eating habits, we are building a strong foundation for our health. This is a journey, and every small, healthy choice you make is a step in the right direction.

Common Vitamins and Where to Find Them

So, should you take a multivitamin?

If you eat a varied diet with plenty of fruit, vegetables, whole grains, and protein, you probably do not need a daily multivitamin. Your food is already doing the job.

If you fall into one of the groups with genuine needs, such as pregnant women, vegans, older adults, or people with absorption problems, then yes, a supplement makes sense. Choose one appropriate for your situation.

If your diet is genuinely limited and you know it, a basic multivitamin can act as a safety net while you work on the bigger picture. Just do not expect it to undo the effects of a poor diet or protect you from serious illness.

And if you are not sure whether you have a deficiency? Do not guess. Ask your GP for a blood test. It takes the guesswork out of the equation and means you can target exactly what you need, rather than spending money on things you do not.

The bottom line

Peace of mind, as mentioned earlier, is a valid reason to take a multivitamin, as long as expectations are realistic. These tablets are not magic. They will not fix your poor diet, add years to your life or shield you from disease. But for some people, in some situations, they do provide genuine support.

The basics matter more than any supplement: eating as well as you can, moving your body, and getting enough sleep. These measures have far stronger evidence behind them.

If you want to take a multivitamin, choose a simple, affordable one. Ignore the expensive "personalised" packs, high-strength formulas and premium brand names. A basic supermarket own-brand will do the same job for a fraction of the price.

And if something does not feel right, or you are worried about your energy levels, your diet, or whether you might be lacking something, speak to your pharmacist or GP. They can help you figure out what you actually need, rather than what the marketing wants you to believe.

Spend your money on things that actually make a difference.

References

1. Loftfield E, et al. Multivitamin Use and Mortality Risk in 3 Prospective US Cohorts. JAMA Network Open. 2024;7(6):e2418729 ↩
2. Vyas CM, et al. Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the COSMOS randomized clinical trial. American Journal of Clinical Nutrition. 2024 ↩
3. NHS. Vitamins and Minerals. Accessed February 2026 ↩
4. NHS. Vitamin D. Accessed February 2026 ↩
5. National Diet and Nutrition Survey. Years 9 to 11 (2016/17 to 2018/19). Public Health England. Accessed February 2026 ↩
6. British Dietetic Association. Supplements: Food Fact Sheet. 2019. Accessed February 2026 ↩

This article is for general information. It doesn't replace advice from your own doctor, pharmacist or prescriber.