When is the best time to take vitamin D?

Take vitamin D with a meal that contains some fat; the time of day matters less than the meal. In a 50-person trial, a single 50,000 IU dose of vitamin D3 reached a peak blood level about 32% higher after a fat-containing breakfast than a fat-free one. No trial we cite compares morning with night.

What the trials found about timing

Vitamin D is fat-soluble, so it makes sense that fat in a meal helps it absorb. Two studies back that up, and one is much stronger than the other.

• The stronger study. 50 healthy older adults, after a 12-hour fast, took one 50,000 IU dose of vitamin D3 with either a fat-free or a fat-containing breakfast. Peak blood vitamin D3 at 12 hours was 32% higher (95% CI 11% to 52%) with the fat-containing meal. The type of fat (the ratio of monounsaturated to polyunsaturated) made no difference. Limits: one day, a single dose 25 times a 2,000 IU softgel, and a blood level rather than a health outcome.
• The weaker study. 17 patients taking vitamin D for medical reasons, at doses of 1,000 to 50,000 IU a day, moved their usual dose to the largest meal of the day. Their average blood 25-hydroxyvitamin D rose from 30.5 to 47.2 ng/mL over 2 to 3 months. Limits: no control group, 17 people, a wide dose range, and patients who were not responding to treatment before. It agrees in direction with the first study but should not be leaned on.

Morning or night: does it matter?

We found no trial that compares taking vitamin D in the morning with taking it at night, so we cannot tell you one is better. The practical answer is the meal: take it with the largest or most fat-containing meal you reliably eat, at whatever time that is, and take it at the same time each day so you do not forget or double up. Our label directs one softgel daily, with no time of day specified.

Can you take vitamin D3 at night, or will it keep you awake?

No study we cite tests vitamin D at night or links it to wakefulness or sleepiness, so we cannot say either way from evidence, and we make no sleep claim for it. If a dose at a particular time of day does not sit well with you, move it to another meal. If you notice unusual sleepiness, confusion or dizziness after starting, stop and ask a clinician. Confusion and apathy are listed among the signs of high blood calcium, which is the safety issue to rule out (see vitamin D side effects).

Empty stomach, fasting, and the softgel's own oil

The fat-free comparison in the stronger study was a meal without fat, not an empty stomach, so no study we cite tests an empty stomach directly. The trial supports the direction (some fat helps) and no more. Our softgel is vitamin D3 in soybean and corn oil inside a gelatin shell, and no study we cite shows whether that oil does the job of the fat in a meal, so the meal advice stands. If you fast strictly, the softgel contains oil and gelatin; take it in your eating window.

What our label says

Electric Tiger Vitamin D3 directs adults to take one softgel (50 mcg, 2,000 IU) daily, or as directed by a health care professional, as low as $15.35 a bottle on subscription. Count any other vitamin D you take: the adult upper limit is 100 mcg (4,000 IU) from all sources. The reference numbers are in how much vitamin D should you take a day.

Questions people ask

When should I take vitamin D3, and what is the best time?

With a meal that contains fat, at a time you can repeat daily. The trial support is for the fat, not the clock.

Is morning or night better?

We found no trial comparing them. Choose the meal, then keep the time consistent.

Can I take vitamin D3 on an empty stomach?

You can, but the one trial we cite shows better absorption with fat in the meal than without, so a meal is the better habit. An empty stomach was not itself tested.

Will vitamin D3 break a fast?

Our softgel is vitamin D3 in oil with a gelatin shell. If your fast is strict, take it with your first meal.

When should I take vitamin D3 with calcium, K2 or other supplements?

This softgel contains no calcium and no K2, so those have their own directions on their own labels. We found no timing trial for pairing vitamin D with them, so we cannot give a time. Count the vitamin D in any combined product toward the 100 mcg limit.

How and when to take it, if I take a different amount than 2,000 IU?

The meal advice applies at any dose, but the amount is a different question: see the dosage guide above, and ask a clinician before going over 100 mcg (4,000 IU) from all sources.