NEW YORK, June 2: When browsing the supplement aisle, you’ll often see multivitamins, omega-3s, and probiotics taking up most of the shelf space. However, if your multivitamin doesn’t include vitamin D, your doctor might suggest adding a separate vitamin D supplement to your daily routine. Known as the “sunshine vitamin,” vitamin D is something many people don’t get enough of, so if you’re wondering when is the best time to take it, here’s what you need to know.

What is vitamin D?

Roxana Ehsani, M.S., RD, CSSD, explains that vitamin D is one of four fat-soluble vitamins (the others being vitamins A, E, and K). Our bodies produce vitamin D when exposed to sunlight, and we can also obtain it through certain foods. Vitamin D plays many essential roles in the body, including supporting the immune system, muscle and nerve function, and helping the body absorb calcium.

Despite its importance, research shows that about 25% of Americans are deficient in vitamin D. This deficiency can be attributed to limited dietary sources of vitamin D, reduced sun exposure during winter, living in areas with little sunlight, or habits like covering the skin when outdoors.

The recommended daily intake of vitamin D for most older adults is 20 micrograms (800 international units, IU). For context, one egg or a 3-ounce can of tuna contains just over 1 mcg, 3 ounces of sockeye salmon has around 12 mcg, and 3 ounces of trout offer about 14 mcg. Unless you consume fish like salmon or trout daily or take cod liver oil (which has 34 mcg), it’s difficult to meet the recommended intake through diet alone, as most foods provide only small amounts.

In the U.S., fortified milk is the main dietary source of vitamin D, containing approximately 100 IU per 8-ounce serving. However, to meet the daily value, you’d need to drink over a quart of milk each day. Milk consumption has been decreasing in recent years, which some experts believe contributes to rising vitamin D deficiency rates.

Why take a supplement?

Because of these challenges, many people choose to take vitamin D supplements. However, it’s important not only to take the correct dose but also to ensure your body absorbs it effectively. Here’s what you should consider when deciding how and when to take your vitamin D.

Morning or evening?

Current scientific consensus indicates that the time of day you take vitamin D doesn’t significantly affect how well it’s absorbed. Some prefer taking supplements in the morning as part of their routine before the day starts, while others keep them handy in the evening after finishing chores. The key is consistency—pick a time you can stick to so you don’t forget.

What factors affect vitamin D supplementation?

Several factors can influence your vitamin D levels or your need for supplementation. Health conditions like osteoporosis, osteopenia, depression, kidney or liver disease, and a family history of neurological disorders may impact your vitamin D status.

David Davidson, M.D., stresses that people with absorption issues, such as those with inflammatory bowel disease or who have undergone gastric bypass surgery, should work closely with their doctors to tailor their vitamin D dosage and timing.

Body size can also affect how vitamin D is absorbed, so individualized advice from your healthcare provider is important before choosing a supplement. If you experience side effects like nausea, constipation, or changes in appetite after taking supplements, consult your doctor.

Personal preference matters

Incorporating vitamin D into your daily habits is essential to ensure you take it regularly. Many people find success by “habit stacking,” which means pairing vitamin D intake with another daily routine, such as brushing teeth. For example, placing your supplements next to your toothbrush can serve as a helpful reminder.

Always check with a healthcare professional to determine the best timing for you, but generally, the “best” time to take vitamin D is whatever fits your schedule and ensures consistency.

Take vitamin D with food

Since vitamin D is fat-soluble, taking it with a meal containing healthy fats can improve absorption. For example, if you eat almond-butter toast in the morning, take your supplement then, as almond butter has healthy fats. Similarly, a salad with walnuts and vinaigrette at dinner is a good pairing. You might also take vitamin D with a glass of whole milk or yogurt, which provides calcium that works synergistically with vitamin D.

If eating with your supplement isn’t always practical, such as when meals are on the go, discuss your schedule with a healthcare provider to find a good alternative.

Types of vitamin D

There are two main forms of vitamin D: D2 and D3. Vitamin D2 is found in UV-exposed plants, fungi, and fortified foods, while D3 comes from sunlight and animal-based sources. Both forms are beneficial, but D3 is more bioavailable, meaning your body uses it more efficiently. This means you may need a higher dose of D2 to get the same effect as D3.

Before starting supplementation, talk to your healthcare provider about which form is best for you. If you’re already taking vitamin D, verify that you have the correct type.

The best time to take vitamin D is when it fits seamlessly into your daily routine, making it easier to remember. Choose vitamin D3 over D2 for better absorption. Ideally, take your supplement with a meal containing fat to maximize uptake. For example, if you prefer taking vitamin D early in the morning or right before bed, accompany it with a small serving of nuts or nut butter to boost absorption and gain additional nutritional benefits.