Best Time to Take Calcium: Timing, Absorption and Safety Guide

Split your calcium across the day and keep each dose at about 500 mg or less. Memorial Sloan Kettering’s example is 500 mg in the morning and 500 mg in the evening for 1,000 mg a day, and calcium carbonate goes with a meal while calcium citrate can go with or without food.

Morning or night: which is better?

The sources give no morning-versus-night ranking. They give per-dose limits (about 500 mg, or 500 to 600 mg per UAB), spacing, and food rules by form. MSKCC calcium supplement guide says that if you take more than 500 mg of calcium supplements a day, you should take it in divided doses. Purdue Extension calcium supplement guidelines says not to take more than 500 mg at one time and to allow 4 to 6 hours between doses.

UAB calcium supplement tips gives a slightly higher line of 500 to 600 mg at one time. It also suggests that if your breakfast is already high in calcium, such as cereal with milk or calcium-fortified orange juice, you may want to save your supplement for later in the day.

Pick a time you will repeat every day. MyHealthfinder, from the U.S. Office of Disease Prevention and Health Promotion, suggests taking it at the same time each day, for example when you brush your teeth before bed.

How the form changes the timing

Can you take vitamin D and calcium together at night?

Vitamin D helps your body absorb calcium, and some supplements combine the two. NIAMS calcium and vitamin D guide from the National Institute of Arthritis and Musculoskeletal and Skin Diseases says vitamin D helps your body absorb the calcium you get from food. Purdue Extension notes that vitamin D is often supplemented along with calcium, and MedlinePlus notes that some calcium supplements already include vitamin D. For bedtime timing, confirm with a pharmacist or your provider.

The timing rules that matter are about dose size, spacing and the medicines and minerals listed further down this page, not about putting vitamin D and calcium in the same routine. MyHealthfinder suggests tying a daily dose to a routine, such as brushing your teeth before bed.

Calcium citrate vs. calcium carbonate: which should you choose?

Both forms are absorbed well, according to UAB. The choice usually comes down to your stomach acid, your medicines and how your gut handles each one.

What is the best calcium citrate?

The best calcium citrate is one that meets the USP standard and matches the dose you need. MedlinePlus says to look for the word “purified” or the United States Pharmacopeia (USP) symbol. Purdue Extension explains that USP letters mean the tablet meets USP standards for the amount of elemental calcium on the label and how well it dissolves, and that a USP calcium tablet must dissolve in 30 to 40 minutes.

Avoid calcium made from bone or dolomite, or from unrefined oyster shell without the USP symbol. MSKCC and MedlinePlus both warn that these can contain lead or other toxic metals. Purdue Extension states that under USP standards, a calcium tablet must contain 90-110% of the elemental calcium listed on the supplement label.

To see how one calcium ingredient has been tested in people, read our Aquamin calcium human studies page.

How do you take calcium for the best absorption?

Use these rules from the major sources:

• Keep each dose at about 500 mg or less (MSKCC, Purdue, MedlinePlus).
• Spread your daily total across the day, with 4 to 6 hours between doses (Purdue).
• Take carbonate with meals and citrate with or without food (MedlinePlus).
• Get enough vitamin D, since it helps your body absorb calcium (NIAMS).
• Take it at the same time each day so it becomes a habit (MyHealthfinder).

Should a 70-year-old take calcium?

It depends on what you eat and what your provider finds. MedlinePlus says many people get enough calcium from their normal diet, but older women and men may need extra calcium to help prevent osteoporosis, and your health care provider will tell you if you need a supplement.

The NIH reference values are set by sex and age. MyHealthfinder lists them like this:

These are reference values for the whole day, from food and supplements combined. A reference value is not a personal dose, and your provider sets your amount. The NIH upper limit, as quoted by Cleveland Clinic, is 2,500 mg a day for adults 19 to 50 and 2,000 mg a day for adults 51 and older.

Osteoporosis is the reason this matters for older adults. MyHealthfinder reports that four in 20 women and one in 20 men older than 65 in the United States have osteoporosis. If your bones are already thinning, our osteopenia calcium and vitamin D safety guide covers that situation in more detail.

Is calcium from food the best source for seniors?

Yes, food comes first. MyHealthfinder says getting calcium from foods is best, and MSKCC says the best way to get calcium is through the food you eat. A supplement is for the gap. MSKCC notes that your doctor “may suggest” a supplement if you find it hard to get enough from food alone.

Source: MSKCC calcium supplement guide, Calcium-Rich Foods and Drinks table.

MSKCC also notes that older people may absorb calcium citrate better than carbonate, which is why citrate often comes up for older adults.

Should seniors take calcium tablets?

Ask your provider first. The NIAMS guide says to talk to your health care provider if you are thinking about taking a calcium supplement. MedlinePlus says the decision should balance the benefits and risks of extra calcium, and that taking extra calcium over a long period raises the risk of kidney stones in some people.

Can you get enough vitamin D from food alone?

For most people, it is hard. NIAMS says that in the United States most people do not consume enough vitamin D to meet recommended intakes. Its list of food sources is short: fish such as trout, salmon, tuna and mackerel, plus foods fortified with vitamin D. Most of the vitamin D Americans get from food comes from fortified foods, mainly milk, some yogurts, ready-to-eat cereals and orange juice.

Your skin can make vitamin D from sun exposure, but NIAMS adds that many people still have low vitamin D status. MSKCC says it can be hard to get enough vitamin D from sunlight and foods alone. The NIAMS reference is 15 micrograms (600 IU) a day for children and adults ages 1 to 70, and 20 micrograms (800 IU) for adults older than 70.

Are calcium tablets safe during pregnancy?

Ask your prescriber or midwife before you start, and bring your full list of supplements. Cleveland Clinic notes that adequate calcium has been shown to help regulate blood pressure during pregnancy, and that calcium may help prevent pregnancy-related complications such as hypertension and preeclampsia. Cleveland Clinic also advises talking with your healthcare provider before beginning calcium supplementation to find out how much you might need.

The NIAMS table lists separate reference amounts for pregnant and breastfeeding teens and adults. Use the figure your prescriber gives you, not a number from a website.

Do calcium tablets help with muscle cramps?

The NIAMS calcium guide does not show a link between calcium tablets and muscle cramps. It does say calcium helps your muscles work properly. Cleveland Clinic lists muscle pain among the signs of a calcium deficiency, along with fatigue and tingling in the hands and feet.

If cramps keep coming back, bring them to your provider rather than adding a tablet on your own. Your provider can check whether low calcium is part of the picture.

What side effects should you watch for?

Which medicines can interact with calcium?

Confirm any of these with your prescriber or pharmacist before you combine them.

• Antibiotics and iron pills. MedlinePlus says calcium supplements may change the way your body absorbs some medicines, including certain types of antibiotics and iron pills. UAB says to take calcium citrate if you take an iron supplement.
• Bisphosphonates such as alendronate (Fosamax) and risedronate (Actonel). MSKCC says to take your calcium supplement at least 30 minutes after the bisphosphonate.
• Diuretics and antacids. MSKCC says to talk with your doctor before taking calcium if you take diuretics (water pills) or antacids for indigestion.
• Strong prescription antacids such as Nexium, Prilosec or Axid. UAB says to take calcium citrate with these.

Before you start: a short checklist

• Check the label for the elemental calcium per tablet and the USP symbol.
• Ask your provider how much calcium you need, including whether you need extra for osteoporosis. MSKCC says that if you have osteoporosis, you might need more calcium, vitamin D, or both.
• Tell your provider if you have a history of kidney stones, too much calcium in the blood, parathyroid problems, or heart disease. MSKCC lists these as reasons to talk with your doctor first.
• Tell your pharmacist about every medicine you take, including antacids and iron.
• Check today’s price and label details at the store or on the brand’s site, since prices change.

Cleveland Clinic calcium overview and MedlinePlus calcium supplements page are good next reads if you want the full picture on calcium’s roles in the body.

By BackToHealthTroy.com Editorial Team

This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.