How Long Does It Take for a Vitamin D Supplement to Start Working?

Many doctors recommend that their patients take a daily vitamin D supplement.  This is because it can help to support strong bones, heart health, immune system strength, and even keep your mood better. Unfortunately, about a third of adults across the United States aren’t getting the levels they need to truly benefit from what it has to offer.

Do You Need a Vitamin D Supplement?

Without a blood test, the only answer anyone could give you is “possibly”. You might need to take a vitamin D supplement if you are one of the third of US adults getting insufficient amounts every day without it.  Insufficient amounts should be taken seriously as a 2016 peer-reviewed study analysis showed that getting too little can raise your risk of premature death from any cause.  Moreover, research published in the Journal of the American Medical Association (JAMA) revealed that over 80 percent of people who had been hospitalized with COVID-19 also had low levels of vitamin D in their blood.  It is not clear whether those two issues were directly connected, but they were interesting and statistically significant findings, nonetheless.

The only way to measure an individual’s levels is through a blood test. That said, many doctors are recommending a vitamin D supplement to their patients even without a test, as supplementing 1,000 IU of D3 (or D2 if you prefer plant-based sources, though D3 – sourced from sheep lanolin, which is obtained without harming the animal – is preferable if you are not following a strict vegan lifestyle) can come with notable potential benefits but is highly unlikely to place the patient anywhere near toxicity levels for the nutrient.

How Long Does It Take a Vitamin D Supplement to Work?

If you’re looking to try to boost your levels quickly, you might be tempted to head outside and spend a lot of time in direct sunlight. Sunlight is, after all, the primary way that the body gets the nutrient in the first place. Your skin absorbs the sunlight and produces its own. However, doctors warn against this method in large amounts. 

A handful of minutes – no more than 20 – can be good for you, but anything beyond that increases your risk of skin cancer and is unlikely to efficiently build your levels in any sustainable year-round way. Moreover, if you get too much direct sunlight, researchers have found that the sunlight can degrade the nutrient in your skin, going from working for you to working against you.

Unless you suffer from a fat malabsorption condition, a vitamin D supplement and dietary sources are usually seen as the best way to ensure adequate levels are consistently being reached. 

There are many factors that can dictate how long it will take for your levels to reach where they should be. If you have been deficient, it will depend on the size of the starting deficiency. That said, for most people who start using a vitamin D supplement and eat a generally healthy diet that includes some foods containing the nutrient, such as fish, you can expect to consistently maintain proper levels at around the three month mark after starting your protocol.