Popping all your vitamins and supplements at night might be the easiest way to remember to take them, but sleep and supplements aren't always friendly bedfellows. Taken too close to lights out, some supplements can interrupt your sleep, or make it hard to fall asleep in the first place. Read below to learn more about what vitamins and minerals you should avoid before bed and what supplements may actually benefit sleep.
Vitamins and supplements to avoid before bedtime
To preserve your sleep hygiene, think twice about taking the following supplements before bedtime.
Vitamin B12
“B vitamins, particularly B12, play a role in both energy production and neurological function, so these would be better to take as you start your day,” says Hannah Holzum, RDN, the founder of Wholesome Nutrition Co.
Keep in mind that studies have linked insomnia to both low levels of vitamin B12 and elevated amounts of the vitamin. Best practice is to ensure that you take just enough vitamin B12 to support your health, while timing your dosage appropriately. The average adult should consume around 2.4 micrograms (mcg) of vitamin B12 daily, with slightly higher intakes of 2.6 mcg and 2.8 mcg recommended for pregnant and lactating women, respectively.
Calcium
Taking calcium before bedtime can disrupt sleep since it can negatively affect magnesium absorption, a mineral which supports sleep.
But don't skip it altogether: Calcium deficiency may also mess with your shut-eye. It’s best to stick to the recommended daily value of calcium supplementation, which is around 1000 milligrams (mg) (1200 mg daily for adults over 51 years), or simply consume calcium through dietary sources — research on the effect of dietary sources of calcium like milk and milk-based products on sleep shows that they may enhance sleep quality.
Multivitamins
Since most multivitamins contain nutrients like calcium and B vitamins, it’s best to avoid taking them as part of your bedtime routine for the reasons listed above. Plus, Holzum points out that since most multivitamins contain fat-soluble vitamins that require dietary fat to absorb best in the body, they're “best taken at a meal, rather than right before bed.”
Of course, not everyone will need to take a multivitamin for optimal health if you meet your nutrient needs from diet alone. However, daily multivitamins can be beneficial for those trying to conceive, pregnant and lactating women, those with malabsorption issues as well as older adults with low appetite who are at risk for inadequate nutrient intake.
Supplements that are good for sleep
Although some supplements are not ideal to take before bedtime, others may actually benefit sleep.
Magnesium
Magnesium is a vital mineral in helping support sleep. A 2024 study on magnesium threonate found that when people took this form of magnesium two hours before going to bed, they had improved sleep quality (especially deep sleep), mood, energy, alertness and daily activity and productivity. The average adult should consume around 310 to 420 mg of magnesium daily minimum, with higher doses recommended for males.
“Magnesium is a popular nighttime supplement for good reason — research suggests it plays a role in regulating neurotransmitters involved in sleep and relaxation,” says Amy Anderson, RDN, the founder of A+ Nutrition reports that. She suggests forms like magnesium glycinate or citrate which are known to be well-tolerated for most people, and in doses between 200 and 400 mg after dinner or before bed. “As a dietitian I enjoy making a little "sleepy mocktail" with magnesium glycinate powder, water and a splash of tart cherry juice to promote a restful night’s sleep!”
Vitamin C
A 2024 study shows that higher serum vitamin C levels are linked to better sleep. Further research confirms that 132 to 191 mg of vitamin C daily can help prevent sleep disorders. The average adult should consume around 75 to 90 mg of vitamin C daily minimum, with higher doses recommended for males, and up to 120 mg daily recommended for people who are lactating.
Iron
If you are iron-deficient, then poor sleep patterns could be your normal. But supplementing with iron daily to ensure your levels are within normal range may help you reclaim healthier sleep. The average man should consume around 8 mg iron daily and the average women should consume 18 mg daily, while those who are pregnant should consume 27 mg daily.
Omega-3 Fatty Acids
A 2024 study reports that higher polyunsaturated omega-3 intake led to greater sleep efficiency, which is the ratio of the time you spend asleep relative to the total time you spend in bed. Experts suggest that omega-3 fatty acid intake may help support sleep by influencing the regulation of serotonin secretion, which in turn can help regulate sleep. The average adult should aim for at least 1.1 to 1.6 grams of omega-3 fatty acids daily, with higher doses recommended for males as well as pregnant and lactating women.
The bottom line
To ensure your sleep is the best it can be, stick to magnesium before bedtime. And even though taking a multivitamin daily may help support your sleep health, take it with your morning meal to prevent any sleep disruption and to enhance absorption. If you’re not sure if your supplement is safe to take before sleep, reach out to a trusted healthcare provider or pharmacist for advice. Enjoying high-quality sleep while nourishing your body with supplements requires a balance of each nutrient that is best for your body, not too much or too little.
Melissa Prest, R.D., D.C.N. is a registered dietitian nutritionist and holds a Doctor of Clinical Nutrition degree from Rutgers University. Melissa owns Kidney Nutrition Specialists, a nutrition practice dedicated to helping individuals living with chronic kidney disease, and is the Foundation Dietitian for the National Kidney Foundation of Illinois where she focuses on disease prevention, health education, and nutrition consultation.