Why is it better to take calcium at night?

Calcium is an important mineral that plays a vital role in bone health, muscle function, nerve transmission, and hormone secretion. Most health experts recommend getting 1,000-1,200 mg of calcium per day, but when you take your calcium supplement can be just as important as how much calcium you take.

There is growing evidence that taking calcium supplements at night may provide greater benefits than taking them during the day. Here are some of the key reasons why it may be advantageous to get more of your daily calcium intake in the evening hours:

Better absorption

Calcium absorption appears to be more efficient at night. Research indicates that the body’s ability to absorb and utilize calcium is controlled by circadian rhythms, and peak calcium absorption occurs between midnight and 2 AM.

During the day, the production of stomach acid tends to be lower, which can limit calcium dissolution and absorption. Taking calcium supplements at bedtime allows absorption to happen when the body is primed to take in calcium efficiently.

Replenishes stores depleted during the day

Our calcium needs are greater during the day when we are active and losing calcium through sweat and waste elimination. By taking calcium before bed, you can help replenish the calcium lost during your waking hours.

This ensures your body has enough calcium to carry out all of its important functions while you sleep. Getting an influx of calcium at night may leave you better supplied for the day ahead.

Combats rises in parathyroid hormone

Our parathyroid glands produce a hormone called PTH that regulates calcium levels in the body. When calcium levels drop too low, the parathyroid releases PTH to stimulate the release of calcium stores from the bones.

Studies show that PTH levels start to rise in the evening if dietary calcium intake has been inadequate during the day. Taking a calcium supplement at night helps keep PTH levels from rising excessively and pulling calcium from your skeleton.

Counteracts cortisol effects

Cortisol is a hormone that helps regulate metabolism and stress responses. Cortisol tends to be highest in the morning and lowest in the evening. This matters because cortisol can deplete calcium from the bones.

By taking calcium supplements at night, you can help counteract the bone-depleting effects of cortisol during a time when cortisol levels are already low. This protective effect helps maintain bone mineral density.

May support melatonin production

Melatonin is an important sleep hormone produced in the brain that helps regulate circadian rhythms and improve sleep quality. Research indicates that calcium supplementation at night may enhance melatonin production. This is likely because calcium is needed as a cofactor in melatonin synthesis.

Promoting restful sleep is another advantage of taking calcium before bed. Getting good sleep is vital for bone health and overall well-being.

Better Sleep

In addition to the ways evening calcium intake can support bone metabolism, taking calcium at night may also promote better sleep. Here’s an overview of how calcium supplementation may improve your sleep:

Helps nervous system relaxation

Calcium plays an integral role in regulating nerve impulses and smooth muscle contractions. As calcium levels fall, nerve cells can become overexcited. Restoring calcium late in the day calms neurological activity and aids muscular relaxation – two prerequisites for falling asleep.

Activates calming neurotransmitters

Calcium is needed for the synthesis of neurotransmitters with sleep-inducing effects, like melatonin, serotonin and GABA. When calcium levels are adequate, the body can more efficiently convert tryptophan into serotonin and serotonin into melatonin. These chemicals quiet the mind and promote drowsiness.

Regulates sleep hormones

As discussed earlier, calcium has an impact on melatonin, cortisol and parathyroid hormone – all hormones that influence the sleep-wake cycle and sleep quality. Calcium helps produce and maintain optimal levels of these hormones so you can sleep soundly through the night.

May reduce leg cramps

Nocturnal leg cramps are a common cause of sleep disruption that may be linked to calcium deficiency. Calcium is essential for proper muscle function. Supplementing with calcium at night may help prevent painful leg cramps from jolting you awake.

Stronger Bones

One of the main reasons to pay attention to your calcium intake is building and maintaining strong, healthy bones. Here’s an overview of how taking calcium at night can benefit your skeletal health:

Slows bone loss

Bone undergoes a continual process of remodeling and turnover. Bones are broken down (resorption) and rebuilt (formation) in a balance that favors resorption as we age. This makes bones weaker and more prone to fractures over time. Consuming calcium before bed helps slow the pace of bone loss to preserve bone mineral density.

Reduces fracture risk

Up to 30% of women over age 50 will suffer an osteoporosis-related fracture. Many fractures result from weakened bone that cannot withstand normal impacts. Supplemental calcium at night strengthens bones and helps prevent devastating breaks.

Supports bone rebuilding

Your skeleton is most active at night while you sleep. This is when old, damaged bone is cleared out and new bone is formed. Calcium is required for optimal bone production. Taking calcium supplements in the evening provides the raw material to manufacture strong, resilient bones.

Potential Drawbacks

While the research points to real advantages of taking your calcium at bedtime, there are also some potential drawbacks to consider:

Possible sleep disturbances

There have been occasional reports of calcium supplements impairing sleep quality or causing vivid dreams and nightmares. High calcium doses may have stimulatory effects in sensitive individuals. Start with a low dose and monitor your sleep response.

Interaction with other medications

Calcium can interfere with the absorption of certain antibiotics and thyroid medications if taken at the same time. To avoid this issue, separate your calcium and other med schedules by at least a few hours.

Possible constipation

Calcium supplements can sometimes cause constipation, bloating or flatulence. Stay well hydrated and get sufficient magnesium to counteract calcium’s binding effects on the bowels. Reduce your dose if GI issues arise.

The Ideal Calcium Dosage

When it comes to the optimal amount of supplemental calcium to take at night, there are a few factors to consider:

Your age

Calcium needs increase as we get older to counteract age-related bone loss. The National Institutes of Health recommends 1,200 mg per day for women over 50 and men over 70.

Menopausal status

Estrogen helps regulate calcium absorption and utilization. After menopause, women’s calcium requirements jump to 1,200 mg daily to offset accelerated bone loss.


Certain drugs like steroids, seizure meds and diuretics can deplete calcium levels. People taking these medications often need supplementary calcium. Discuss your dosage with your doctor.

Health conditions

Malabsorption disorders, kidney disease and some autoimmune diseases increase calcium needs. Work with your healthcare provider to determine your ideal calcium intake.


If you regularly eat calcium-rich foods like dairy, leafy greens, fish with bones and tofu, you may need less supplemental calcium. Get your levels tested to find your optimal dose.

The Best Sources of Calcium

While calcium supplements can help you meet your daily calcium quota, getting plenty of calcium through food should be your first priority. Here are some of the top dietary calcium sources to incorporate in your evening meals:


Plain yogurt is an excellent source of highly bioavailable calcium. Just one cup of yogurt provides around 300 mg of calcium. Choose unsweetened yogurt and top it with fruit, nuts and seeds.


Cheese is one of the most calcium-dense foods. Hard cheeses like cheddar, Swiss and parmesan provide over 200 mg per ounce. Include cheese on salads or as part of a nighttime snack.


If you don’t eat dairy, tofu can be an excellent plant-based calcium source. Calcium-set tofu prepared with calcium sulfate contains about 250-500 mg of calcium per 3.5 ounces.


Canned sardines and salmon are superb sources of bone-building calcium thanks to their edible soft bones. Three ounces of canned sardines supplies over 300 mg of highly absorbable calcium.

Fortified plant milks

Many plant-based milks like almond, coconut and oat milk are fortified with calcium carbonate. Opt for fortified milks to enjoy with your breakfast cereal or evening tea.

Tips for Taking Calcium Supplements at Night

If you are taking calcium supplements, utilize these simple tips to maximize the benefits and absorption:

Take with food

Consuming calcium supplements alongside food enhances absorption. Have your supplement with dinner or a bedtime snack.

Combine with magnesium

Magnesium improves calcium absorption and counters constipation. Look for a calcium-magnesium combined supplement.

Avoid iron supplements

Iron can hinder calcium absorption, so take your iron earlier in the day if possible. If taking both, separate by a few hours.

Increase vitamin D

Vitamin D boosts calcium absorption. Make sure you are getting enough vitamin D from sunlight, food or supplements.

Split your dose

Taking 500-600 mg of calcium at a time is ideal. You can take one dose with dinner and a second before bed.

Common Myths About Calcium and Bone Health

There are many myths and misconceptions surrounding calcium and bone health. Here are some common calcium myths along with the reality:

Myth: All milk products are good calcium sources

Reality: While dairy can provide calcium, full-fat sources are better than low-fat. Skim and nonfat milk have much less usable calcium due to removed milk fat.

Myth: Protein harms bones

Reality: Protein is actually essential for bone strength and health. Recent research found no link between protein intake and fracture risk.

Myth: Vitamin C supplements increase calcium absorption

Reality: Large doses of vitamin C can actually inhibit calcium absorption. Get your vitamin C from food instead of supplements.

Myth: Weight-bearing exercise can fully offset calcium loss

Reality: While strength training is vital for bones, it does not negate the need for adequate calcium intake from diet and supplements.

Myth: Calcium from supplements is poorly absorbed

Reality: Calcium citrate is absorbed equally well from both foods and supplements when taken with meals.

The Bottom Line

Your nighttime calcium intake can have wide-ranging effects on your bones, sleep and overall health. The scientific evidence strongly suggests that supplemental calcium is best absorbed and utilized when consumed in the evening hours.

Aim for 500-600 mg of calcium at dinner or before bed – either through food, supplements or a combination of both. Pair your calcium with magnesium and vitamin D for optimal results.

Timing your calcium properly can help keep your bones strong, your nerves relaxed and your sleep restful so you wake up feeling refreshed and restored.

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