Vitamins and supplements you should not take before bed

Taking all your vitamins and supplements at night may be the easiest way to avoid forgetting, but sleep and supplements don't always go hand in hand in bed.

Taken too close to lights out, some supplements can disrupt sleep or make it difficult to fall asleep in the first place.

To maintain good sleep, consider carefully before taking the following supplements before going to bed.

Vitamin B12

B vitamins , especially B12, play an important role in energy production and nerve function, so it's a good idea to get these vitamins at the start of your day.

Keep in mind that studies have linked insomnia to both low and high vitamin B12 levels. The best way to do this is to make sure you're getting enough vitamin B12 to support your health, and to get the right dose. On average, adults should consume about 2.4 micrograms (mcg) of vitamin B12 per day, with slightly higher recommendations of 2.6 mcg and 2.8 mcg for pregnant and breastfeeding women.

Calcium

Taking calcium before bed may disrupt sleep because it can negatively affect the absorption of magnesium, a mineral that aids sleep.

But don't ignore it entirely: Calcium deficiency can also affect your sleep. It's best to stick to the recommended daily intake of calcium supplements, which is about 1,000 milligrams (mg) (1,200 mg per day for adults over 51), or simply get calcium through food sources—research on the effects of dietary sources of calcium like milk and dairy products on sleep suggests they can improve sleep quality.

Multivitamin

Since most multivitamins contain nutrients like calcium and B vitamins, it's best to avoid taking them before bed for the reasons mentioned above. Additionally, most multivitamins contain fat-soluble vitamins that require dietary fat for best absorption, so they're "best taken with meals, rather than right before bed ."

Of course, not everyone needs a multivitamin for optimal health if they are meeting their nutritional needs through diet alone. However, taking a daily multivitamin may be beneficial for those who are trying to conceive, pregnant and breastfeeding women, those with absorption problems, and older adults with poor appetites who are at risk of nutritional deficiencies.

Magnesium

Magnesium is an essential mineral that helps support sleep. A 2024 study of magnesium threonate found that when people took this form of magnesium two hours before bed, they experienced improvements in sleep quality (especially deep sleep), mood, energy, alertness, activity, and daily productivity. The average adult should consume a minimum of about 310 to 420 mg of magnesium per day, with the recommended dose being higher for men.

Magnesium is a popular nighttime supplement for good reason—research shows it plays a role in regulating neurotransmitters involved in sleep and relaxation. Magnesium glycinate or citrate, which is known to be well tolerated by most people, is taken in doses of 200 to 400 mg after dinner or before bed.

Vitamin C

A 2024 study found that higher serum vitamin C levels were associated with better sleep. Further studies confirmed that 132 to 191 mg of vitamin C per day may help prevent sleep disorders. The average adult should consume a minimum of about 75 to 90 mg of vitamin C per day, with higher doses recommended for men and up to 120 mg per day for those who are breastfeeding.

Iron

If you are iron deficient, poor sleep may be normal. However, taking a daily iron supplement to ensure your blood levels are normal may help you get better sleep. The average man should consume about 8 mg of iron per day, the average woman should consume 18 mg per day, while pregnant women should consume 27 mg per day.

Omega-3 fatty acids

A 2024 study reported that higher polyunsaturated omega-3 intake led to better sleep efficiency, which is the ratio of time you spend asleep to total time in bed. Experts suggest that omega-3 fatty acid supplementation may help support sleep by influencing the regulation of serotonin secretion, which in turn helps regulate sleep. The average adult should get at least 1.1 to 1.6 grams of omega-3 fatty acids per day, with higher recommended doses for men and pregnant and lactating women.

Micah Soto

Update 19 August 2025