The best time to take calcium with vitamin D3

In this article:

• Calcium’s role in the body
• Vitamin D3’s role in the body
• Dosage
• Calcium timing
• Vitamin D3 with calcium timing
• Safety considerations
• The bottom line

In this article

• Calcium’s role in the body
• Vitamin D3’s role in the body
• Dosage
• Calcium timing
• Vitamin D3 with calcium timing
• Safety considerations
• The bottom line

Both calcium and vitamin D3 are essential for bone health, heart health, and the prevention and treatment of osteoporosis. People who are deficient in these vitamins, have osteoporosis, or are at risk of getting osteoporosis are often told to take calcium and vitamin D3. While calcium and vitamin D3 can be sold as separate vitamin supplements, they are often combined in one pill. This is because they are used for similar purposes and because taking vitamin D3 with your calcium supplement helps your body absorb the calcium more effectively.

The timing of when you take a supplement can affect how well it works and may help decrease potential side effects. Here, we’ll go over the best time to take calcium with vitamin D3 and other important considerations when combining calcium with vitamin D3.

The role of calcium in the body

Calcium is a mineral that plays many important roles in the body. According to the National Institutes of Health (NIH), calcium is a primary element found in bones and teeth, and it helps ensure that the body is able to move strongly and with flexibility. Calcium is also an important part of our circulatory system, helps muscles function properly, and plays a role in nerve transmission, hormonal secretion, and blood clotting.

As the NIH notes, the amount of calcium your body needs depends on your age and sex. For example, adults up to age 50 need about 1,000 mg of calcium per day. But the recommended daily allowance of calcium for women increases to 1,200 mg per day once they turn 51. Men typically don’t need 1,200 mg of calcium until they turn 71.  

If you don’t get enough calcium, you may develop osteoporosis, which is a weakening of the bones. Having osteoporosis can increase your risk of bone loss and bone fractures. Postmenopausal women and people who don’t consume dairy products are most vulnerable to calcium deficiency.

The role of vitamin D3 in the body 

Vitamin D3, also known as cholecalciferol, is necessary for healthy and strong bones, muscles, and nerves. Vitamin D3 also supports a healthy immune system. Additionally, vitamin D3 helps your body absorb calcium.

The amount of vitamin D3 you need depends on your age, sex, and various additional factors. For instance, adults up to age 70 need 600 international units (IUs) per day, but adults 71 and older need 800 IUs per day. People who have a vitamin deficiency may need more than these amounts. It’s best to check with your healthcare provider about the amount you should supplement with.

Vitamin D deficiency is prevalent, with over 1 billion people worldwide experiencing it. It most commonly impacts infants who are breastfed, individuals with dark skin, individuals with obesity, older adults, and people with gastrointestinal disorders such as celiac disease. In children, vitamin D deficiency can lead to rickets, which is a weakening and softening of the bones. It can also lead to osteomalacia in children or adults, which is when your bones and muscles become weak—as well as osteoporosis in adults.

There are two main forms of vitamin D supplements available: vitamin D2 and vitamin D3. Vitamin D2 comes from plant sources, whereas vitamin D3 comes from animal sources like fatty fish and cod liver oil. Some studies have found that taking vitamin D3 can lead to greater amounts of 25-hydroxyvitamin D (calcifediol), which is the major circulating form of vitamin D in the body. That’s why many healthcare providers specifically recommend you take vitamin D3. 

Calcium with vitamin D3 dosage for adults

The calcium with vitamin D3 dosage for adults varies based on age, sex, and whether you’re pregnant or deficient for either vitamin. To maintain bone health, it’s recommended that adults take in 600 IUs of vitamin D daily (and 800 IUs per day if they’re over 70). The daily recommended dose of calcium is 1,000 mg per day for adults up to age 50 and 1,200 mg a day for men and women over the age of 70.

Any pill that combines vitamin D3 and calcium shouldn’t exceed the daily dosages of each of these. “When taken together, the dosages remain the same as when taken separately,” explains Soma Mandal, MD, an internist at Summit Health. “It is important not to exceed the recommended doses unless recommended by a doctor.”

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The best time to take calcium supplements

The two most common types of calcium supplements are calcium carbonate and calcium citrate. Other calcium supplements include calcium sulfate, phosphate, microcrystalline hydroxyapatite, lactate, ascorbate, and gluconate.

The ideal timing of calcium supplementation depends on which type you are taking, according to Annika Kariniemi, RN, APRN, CNP, a family nurse practitioner and founder of ProHealth Medical Weight Loss. “Calcium carbonate (such as Tums or Caltrate) is best absorbed with food, as stomach acid helps break it down,” she explains. “Calcium citrate (like Citracal) can be taken with or without food, making it a better choice for those with lower stomach acid, such as older adults or people on acid-reducing medications.”

Kariniemi recommends avoiding calcium intake too close to bedtime since it may cause digestive discomfort. Dr. Mandel recommends taking calcium with food but not with high-fiber meals, since fiber can bind to calcium and reduce absorption.  

Michelle Routhenstein, RD, CDN, preventive cardiology dietitian and certified diabetes educator at EntirelyNourished.com, suggests taking calcium in smaller doses spaced apart, especially if you need more than 500 mg of calcium per day. In addition, some medications, such as antacids or thyroid medications, can interfere with calcium absorption, so Routhenstein recommends spacing these out from your calcium supplement by at least four hours.

The optimal time to take calcium with vitamin D3 

What about when you are taking both calcium and vitamin D3 together, either in two separate pills or as a supplement that combines them both? When should you take these?

For maximum absorption and comfort, Kariniemi recommends taking calcium and vitamin D in the morning or early afternoon with food. “Morning intake may help with energy levels, while nighttime intake might interfere with sleep in some individuals,” she explains. “While vitamin D plays a role in sleep regulation, there isn’t strong evidence that taking it at night significantly impacts sleep quality for everyone.”

It’s also important to consider sources of calcium and vitamin D3 you are getting with food, and not to exceed the overall daily recommended dosages. For example, foods like dairy products are high in calcium. Vitamin D is found in some dairy products and orange juice products fortified with vitamin D as well as fish like salmon, tuna, sardines, and raw mushrooms.

“I usually advise patients to be aware of their total intake of all sources of calcium and vitamin D, such as diet and supplements, to avoid excessive doses,” Dr. Mandal says. “Excess dosage can potentially lead to hypercalcemia or kidney stones.”

Dr. Mandal highly recommends consulting with a healthcare professional to help ensure that supplementation is safe and effective based on your individual health needs and situation.

Calcium and vitamin D3 safety considerations

Although taking calcium and vitamin D3 together is generally safe and doesn’t cause negative side effects for most people, there are some safety considerations and interactions to keep in mind, according to Kariniemi. These include:

• Since calcium can interfere with the absorption of iron, magnesium, and some antibiotics, it’s best to take them at different times of day.
• Excess calcium supplementation—over 2,000 mg per day—increases the risk of kidney stones, constipation, and even heart issues, so be sure not to exceed this daily amount.
• If you’re taking blood thinners, heart medications, or osteoporosis drugs, consult your healthcare provider before starting calcium and vitamin D supplements, as these can potentially interact with one another or cause unwanted side effects.

Bottom line: Considerations when taking calcium with vitamin D3 

Experts agree that the best time to take calcium with vitamin D3 is in the morning or afternoon. This may help with energy levels and decrease interference with sleep. Still, there’s no strong evidence that taking it in the evening impacts sleep, energy, or mood. “It is important to consult with your healthcare team, including your registered dietitian, to ensure the appropriate dosage and timing of calcium and vitamin D supplementation for you,” Routhenstein concludes.