Vitamin D supplements hold a significant share in the UK vitamin market, accounting for over a third of sales. This popularity is underscored by an increasing body of research linking the nutrient to a variety of health benefits.

Recent studies have highlighted the wide-ranging impacts of this essential vitamin. For instance, research published in the American Journal of Nutrition this summer suggested that vitamin D could potentially slow cellular aging. Meanwhile, findings from the University of Porto in Portugal indicated that vitamin D supplements might also help reduce hair loss.

Eamon Laird, a vitamin D researcher at Trinity College Dublin, emphasizes the vitamin’s importance, noting its role in “everything from preventing bone fractures to bolstering our immune system.” He explains that our bodies have evolved to synthesize vitamin D naturally through sunlight exposure on the skin. However, during the winter months, up to half of the population experiences low levels of this nutrient.

Obtaining sufficient vitamin D through diet alone can be challenging, as it is primarily found in foods like oily fish and egg yolks. Consequently, health guidelines recommend that individuals over the age of four take a daily supplement of 10 micrograms (400 international units) from October to April.

For those who are housebound, have darker skin tones, or wear clothing that covers most of their skin when outdoors, Laird advises a year-round supplementation of 10 to 20 micrograms to ensure adequate vitamin D intake.

People who are housebound, have darker skin tones or wear clothing that covers most of their skin when outdoors, ‘are strongly recommended to take 10-20mcg all year round’, Eamon Laird adds. 

But what is the best way to take it? Eamon Laird assessed some popular options, which we then rated.

TABLETS

BUDGET

Tesco Health Vitamin D 12.5mcg tablets, £4 for 120 tablets

PRICE PER DAY: 3p.

EXPERT VERDICT: These pills tick the box in terms of current UK public health guidelines (10mcg a day). They’re also reasonably priced and at 120 tablets in a tub, should get you through the winter.

However, it’s not clear which form of vitamin D these pills contain – D2 or D3. Studies show D3 supplements are better at raising vitamin D levels. 6/10

MEDIUM DOSE

Healthspan Super Strength Vitamin D, £13.99 for 240 tablets, healthspan.co.uk

PRICE PER DAY: 6p.

EXPERT VERDICT: These contain vitamin D3, the more effective form, and the price is pretty good.

While the dose (25mcg) exceeds UK recommendations, it’s still within a safe level – it’s more in line with US recommendations (20mcg, or 800IU, daily).

This would be beneficial for people who are already deficient, to get their levels up quickly – or those who rarely get outdoor light exposure, or don’t eat foods rich in vitamin D. 7/10

HIGH DOSE

Now Vitamin D3 Max Potency, 50,000IU (1250 mcg), £11.69 for 50, healf.com

PRICE PER DAY: 23p.

EXPERT VERDICT: The dosage in these pills is too high and exceeds the upper safe level of 100mcg (4,000 IU) a day for adults, set by the UK’s Committee on Toxicity.

Vitamin D’s main role is to increase the amount of calcium the gut can absorb from food.

But taking excessive vitamin D can cause too much calcium to build up in the body, which can weaken bones, damage the kidneys – and form calcium deposits in the blood vessels, which can, in extreme cases, lead to heart attacks and death. 2/10

DROPS

Metagenics Vitamin D3 Drops with K2, £22.99 for 30ml, amazon.co.uk

PRICE PER DAY: 7p.

EXPERT VERDICT: Drops can be a good option for people who struggle to swallow pills and those with gastrointestinal disorders – such as Crohn’s disease or coeliac disease – that mean they don’t absorb nutrients in the gut well.

These drops [which provide 25mcg of vitamin D3 and 45mcg of vitamin K2 per three drops] are absorbed in the mouth under the tongue, so the vitamins go straight into the bloodstream and bypass the digestive system.

Vitamin K is being added to supplements as it can prevent excess vitamin D building up in the blood vessels and instead directs it to our bones. But this is only necessary if you’re taking very high levels.

These drops will last 333 days – nearly a year’s supply – so it’s decent value. But drops make it easier to take too much, so follow the instructions carefully. 7/10

PATCHES

Barriere Hello Sunshine Vitamin D3 Patches, £10.49 for 36 patches, healf.com

PRICE PER DAY: 29p

EXPERT VERDICT: One of the major advantages of absorbing vitamin D through the skin is that it is taken direct to the bloodstream, so in theory avoids the possibility of not being absorbed in the gut.

Research has shown that vitamin D can travel through the skin – and the maker quotes a small study involving 30 people where this patch was found to increase blood levels – but we don’t know if the full dose is delivered consistently with a patch.

Each patch contains 100mcg of vitamin D3 – which is the upper limit we should be taking. It’s the second most expensive product here. 5/10

DRINK SHOTS

MOJU Hot Mango Immunity Shot, £1.50 for 60ml, ocado.com

PRICE PER DAY: £1.50.

EXPERT VERDICT: At 10.5mcg per 60ml shot, this contains the recommended daily amount of vitamin D, plus some vitamin C.

But they’ve used vitamin D2 (from seaweed) in this, which isn’t as absorbable as the vitamin D3 form found in most supplements.

Each shot also contains 5.9g sugar (one and a half teaspoons) – which seems unnecessary when you can easily get vitamin D without any added sugar. And it’s not cheap. 2/10

POWDER

Nature’s Finest 2,000IU vitamin D3 powder, £5.73 for 150g, naturitas.co.uk

PRICE PER DAY: 19p.

EXPERT VERDICT: At 50mcg (2,000 IU) per dose, this is still under the 100mcg safe limit and contains easy-to-absorb vitamin D3.

Powder could be an easier option if you don’t like taking pills, as it can be added to cereal or smoothies.

But at £5.73 for just one month’s supply, it is pricey.

It also contains erythritol, a sweetener that may cause stomach cramps, diarrhoea and bloating in some people. 5/10

ENRICHED MUSHROOMS

M&S Baby Chestnut Mushrooms, £1.45 for 200g

PRICE PER DAY: £1.45.

EXPERT VERDICT: These are said to be ‘naturally enriched with vitamin D’ by light exposure.

When mushrooms are exposed to UV light, they produce vitamin D2, the version that’s less well absorbed. And mushrooms alone are not enough to maintain optimum vitamin D levels.

You’d need to consume at least 200g – a whole pack – every day to get the 10mcg minimum. 6/10

FIZZY TABLETS

Holland & Barrett Vitamin D 1,000 IU/25mcg, £4.49 for 20 effervescent tablets

PRICE PER DAY: 22p.

EXPERT VERDICT: These contain the better absorbed vitamin D3. But as with all effervescent tablets the bubbles are created by adding sodium carbonate – basically salt, so not great for people on low-sodium diets, such as those with high blood pressure.

They also contain the artificial sweetener sorbitol, which can cause stomach cramps and diarrhoea; and sucralose, which triggers bloating in some. And they’re quite pricey. 4/10