How Much Vitamin D Per Day is Enough?

Written by
The Manual Team
Medically approved by
Dr Earim Chaudry
Last updated
26th July 2021

In 30 seconds

How much vitamin D per day is enough? Technically speaking, between 10 and 25 micrograms of vitamin D per day is enough, depending on the source. Meanwhile, consuming over 100mg puts you at risk of vitamin D toxicity – and that’s not good.

You might see the amount of vitamin D written in international units (IU). In this case, between 400 and 1000IU of vitamin D is recommended.

What does this all mean in real terms? From early April to September, you should get all the vitamin D you need just from being outside. The rest of the time, you’ll want to get vitamin D from your diet or vitamin D supplements. Supplementation should be no more than 10 micrograms a day (unless your doctor has told you otherwise).

What’s the Right Amount of Vitamin D?

With the coronavirus pandemic having kept many of us at home, there has been a lot of talk about vitamin D deficiency. In a way, that has been positive. Even before the pandemic, an estimated one billion people worldwide were thought not to be getting enough vitamin D.

That’s a big problem – because your bone health, your immune system, your mood, and your muscle strength all depend on your levels of vitamin D. And the vitamin D deficiency symptoms, as a result, can be pretty nasty.

But how much vitamin D per day is enough? And is there such thing as too much vitamin D? Here, we answer those exact questions.

What is Vitamin D?

Vitamin D is one of the essential vitamins for your overall health. Its specific role is in the regulation of the levels of calcium, magnesium, and phosphate in your system – three minerals that are used strong bones, healthy cells, and all sorts of other parts of your body to keep you working as you should.

The cool thing is that you produce one of the D vitamins – vitamin D3, or cholecalciferol – when exposed to the sun. On sun exposure, the ultraviolet rays in the light stimulate its production on your skin. That’s great news because people don’t always get the amount they need from their diet.

Vitamin D3 – the so-called “active form” of the vitamin – can be found in fatty fish (think mackerel, sardines, salmon) and from animal liver, dairy products, and egg yolks. However, people on vegan diets need to focus on mushrooms, which is one of the few plant products that have vitamin D in them. However, that’s vitamin D2, a less potent form of the vitamin.

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What Happens if You Don’t Get Enough Vitamin D?

Vitamin D keeps your bones, your muscles, and your general well-being shipshape. And if you don’t get the right amount, you may experience some of the symptoms of vitamin D deficiency.

These include medical conditions that affect your bones, such as:

  • Rickets, in very extreme cases. This is when bones soften due to low vitamin D levels. It is most common in children and results in bone deformities.
  • Osteoporosis. As you age, your bones won’t be as strong as they once were. Osteoporosis is the condition in which your bones lose their density and become more liable to break. Vitamin D deficiency makes it more likely.
  • Osteomalacia. This is a condition characterised by weakened bones and bone pain. It’s similar to rickets but it’s normally found in older populations. Rather than the deformities you see in rickets, fractures are much more likely.

Less healthy bones are not the only problem you might encounter as a result of low vitamin D. Fatigue, depression, and a less powerful immune system are all possibilities too.

How Much Vitamin D Per Day is Enough?

The risks of vitamin D deficiency — like all vitamin deficiencies — are serious. But how much vitamin D per day is enough to avoid them? And what’s the optimum level of vitamin that you need?

According to most recommendations, it is best to receive between 10 and 25 micrograms of vitamin D per day. This equates to 400 to 1000 international units of vitamin D.

To put that into perspective, a microgram is a thousandth of a milligram, which itself is a thousandth of a gram. 10 micrograms are equal to 400 international units. 

Note: Manual’s Complete Blood Test will measure 7 essential markers for a complete health check-up. This includes vitamin D, vitamin B — and also testosterone, triglyceride, cholesterol, thyroid, and HDL.

Vitamin D in Your Diet

A vitamin D supplement usually contains 10 micrograms of vitamin D. The NHS is very clear that you should not be taking more than this daily, as it can cause problems (which we’ll come to below).

Instead, between early April and September, you should get enough vitamin D from the UK sunlight. During the rest of the year, particularly in the winter months, food is your best option. You can receive vitamin D from the following sources, according to the US National Institutes for Health (NIH):

  • Trout (85g): 645 IU, or 16mg
  • Salmon (85g): 570 IU, or 14.25mg
  • Mushrooms (60g): 366 IU, or 9.15mg
  • Fortified soy, almond, or oat milk (230ml): 100-144 IU, or 2.5-3.6mg
  • One large, scrambled egg: 44 IU, or 1.1mg

Other oily fish, as well as fortified breakfast cereals and fruit juices, are also good sources of vitamin D.

As a result, if you don’t think you are getting enough vitamin D from the sun, a fillet of trout or some mushrooms daily will be enough to keep your risk of vitamin D deficiency low.

What Happens if I Get Too Much Vitamin D?

Vitamin D is great for your health. However, it’s always possible to have too much of a good thing. High doses of vitamin D can cause health problems – largely caused by the build-up of calcium. These can include:

  • Bone pain
  • Kidney stones and other kidney problems
  • Nausea and vomiting
  • A need to urinate

That’s why, when you are taking multivitamins or a daily supplement without medical advice, you should only take the recommended dose.

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Key Takeaways

So, how much vitamin D per day is enough? Somewhere between 10 and 25 mg is best to aim for. Again, that’s 400 to 1000 IU a day. If you don’t get the required levels from the sun, your diet is the best source.

If taking vitamin D supplements, don’t overdo it. A too-high dose of vitamin D can also cause health problems.


  1. pinder Sahota (2014). Understanding vitamin D deficiency:


  2. HEART UK – Vitamin D:

  3. – Vitamin D:

  4. National Institutes of Health – Vitamin D:

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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