Vitamins and supplements are consumed around the world every day. From the common vitamins like C and E to exotic exracts and oils, taken individually or as multivitamins, this multi billion dollar industry exists because people are driven by a natural instinct to protect, preserve, and improve their health and wellbeing. But simply purchasing supplements is a waste of money or even potentially dangerous if they are not consumed properly. What is the best time of day to take vitamins? What are the medication interactions to watch out for? What if you’re pregnant? We address these questions and more to help you get the most from vitamins and supplements.
Best time to take vitamins: a general rule
As a general rule, most manufacturers and experts recommend taking vitamins and supplements in the morning after your first meal. This is often the recommended direction for use you can find on the packaging or product information guide for most supplements on the market.  
The purpose of taking your vitamins after a meal is not so much about maximizing their absorption (with a few exceptions; we’ll get to that later) as much as it is to simply prevent digestive issues.
Depending on the vitamin or supplement, ingesting them on an empty stomach could lead to stomach pains, heartburn, acid reflux, nausea, and even a bad case of diarrhea. These symptoms often happen when you overdose on vitamins and minerals. When you jump start your day with concentrated forms of vitamins and supplements instead of acquiring them with normal food intake, the result can be effectively similar to a sudden spike of temporary overdose.    
When it comes to vitamins and supplements, food acts as a sort of buffer, preventing rapid absorption of super concentrated nutrients in the gut and the bloodstream. While quick absorbtion may often be considered a desirable feature, the human body is not built for sudden spikes in nutrient absorption. That is why taking some vitamins and supplements on an empty stomach may sometimes result in undesirable side effects for some people.
Since fat soluble vitamins are stored in the body through fat cells, you should be cautious about taking fat soluble vitamins in excessive dosages. What are fat soluble vitamins? Read on.
Not all vitamins are the same
The best way to take vitamins and supplements varies according to what the active ingredients of the supplements are, and also their purpose, and the body type of the consumer. In this section we will discuss the differences when it comes to taking fat soluble vitamins, water soluble vitamins, B vitamins, and prenatal vitamins.
We will also list common drug prescriptions and their interactions with nutrient levels and vitamin supplementation.
The four fat soluble vitamins are vitamins A, D, E, and K. Unlike water soluble vitamins, the body only requires small doses of fat soluble vitamins. Furthermore, high doses have been shown to cause undesirable side effects and toxicity. 
Because of the small dosage requirements, fat soluble vitamins can be acquired through diet alone, with the important exception of Vitamin D, which your body produces when you’re exposed to sunlight.
If you decide to include fat soluble vitamins in your supplements regimen, it is best to take them together with a fatty meal. Some studies suggest taking fat soluble vitamins with fish or cod liver oil to boost absorption especially for lactating women. 
To maximize the health benefits of both fat soluble vitamins and the fats you consume them with, it is sensible to opt for healthy oils such as flaxseed or olive oil. Eating nuts, seeds, and even avocados alongside fat soluble vitamin intake also boosts absorption. Some studies suggest that it may be best to avoid taking Vitamin D at night to avoid sleep disturbance. 
Vitamin C and all the B vitamins (thiamine as B1, riboflavin as B2, niacin as B3, pantothenic acid as B5, pyridoxine as B6, biotin, folic acid, and cobalamin as B12) are water soluble vitamins. Unlike some of their fat soluble counterparts, humans are incapable of synthesizing their own water soluble vitamins, and must rely on exogenous sources such as ensuring adequate supply through healthy diet, and/or taking supplements.
Unlike fat soluble vitamins, water soluble vitamins do not need to be consumed with a meal containing some fat in order to be consumed - in fact it’s generally fine to consume them whenever you like, with some exceptions that we will discuss below, and bearing in mind the general rule to take supplements together with food. It’s also worth remembering that dehydration can adversely impact absorbtion of water soluble vitamins.
One good thing about water soluble vitamins is that you’re unlikely to overdose on them because excess water soluble vitamins are normally excreted through urine. With a few exceptions, the body generally doesn’t store excess water soluble vitamins. You even lose water soluble vitamins through sweat, but it’s generally agreed to be of negligible impact. 
When it comes to B vitamins, you know you took too much when your urine is bright yellow and stays that way for half the day. If the color bothers you, you can always drink copious amounts of water and urinate until the color goes back to normal. Note that some B vitamin supplements include caffeine or other energy boosting substances; these should clearly be avoided at night to prevent sleep disturbance.
In certain cases, taking vitamin C on an empty stomach may causes gut problems and sometimes lead to diarrhea. This is why it would be better to take vitamin C with a meal or to take “buffered” forms to make them easier on your stomach. You can also lower the dosage by either cutting the tablet in half or to simply buy a smaller-dosed vitamin C and spacing out your consumption through the day.
Best time to take Prenatal Vitamins and Minerals
For most people, the only vitamins and supplements they need to worry about are those that belong in either fat soluble or water soluble vitamin families. However, for those who may want a kid or two, they have to account for prenatal vitamins and minerals.
Prenatal vitamins are strongly recommended for pregnant women. Folic acid is a must-have, and iron, Omega 3s (in the form of DHA and EPA), zinc, and magnesium are also typicaly taken as prenatal supplements. While similar rules apply when it comes to absorption, there are a few instances where expecting moms need to do a little something extra to maximize vitamin and supplement potency.
Women who plan on conceiving should plan ahead when it comes to vitamins and supplements. For folic acid and iron, it’s best to take them at least 30 days before conceiving.
For omega 3s DHA and EPA, it’s a good idea to start as much as six months before pregnancy because being pregnant automatically reduces the overall DHA and EPA content of the body. Supplementing well ahead of conception should also help provide the baby enough DHA and EPA, preventing development issues associated with deficiency.
Other than planning ahead, generally speaking prenatal vitamins (as multivitamins) are best taken during lunch time or after you’ve had a good meal to absorb them properly, especially since some nutrients in a prenatal multivitamin could be fat-soluble.
For zinc, it’s best to take it with a meal as taking zinc supplements on an empty stomach could result to nausea, especially when taken in excessive amounts. 
The best time to take magnesium is just before you sleep. It’s because magnesium is known to help promote quality sleep as well as prevent the kind of leg cramps that happen at night. 
There is sufficient evidence to suggest iron supplementation is best when taken on an empty stomach. It’s also absorbed better when ingested alongside vitamin C as vitamin C helps the body convert iron into a more bioavailable form. 
Regardless of when or how you take your prenatal vitamins, what matters is you remember to take them every day before and during pregnancy. If it makes you feel sick or nauseous in the morning, take your prenatal vitamins at night.
Is it a good idea to space out your vitamin intake through the day?
Although there are multivitamins on the market that combine various vitamins, minerals, herbs, and other nutritional compounds into a single “one a day” pill, many people still take multiple pills a day. If you take multiple pills a day, is it a good idea to space them out through the day, or is it fine to take them all at once?
There are pros and cons to either approach. The advantage of taking them all at the same time is the sheer convenience of only having to remember to take them once a day, though this advantage can be reduced with the help of software or even simply positive habit formation. On the other hand, the advantage of taking supplements at different times through the day is to do with how your body, and in particular your digestive system, interacts with them.
Taking multiple supplements with a sensitive stomach
For people with sensitive stomachs who experience adverse reactions with vitamins, here are some tips:
For minerals, it would be better to space them out given multiple mineral intake at once affects absorption. Some minerals also affect vitamin A absorption. If you’re taking vitamin A, it’s better to take it separately than together with minerals.
One specific pain point commonly faced by people who prefer to space out their pill consumption throughout the day is the sheer practical problem of having access to your pills when you’re not at home. In a previous post we discussed how studies have shown that travel is the leading cause of missed medication coses, but even without travel it isn’t always easy to have access to your pills with busy daily lives. The remedy to this is to use a pill organiser, which can make your medication and supplements easily accessible wherever you are, and generally helps with adherence issues like peventing double-dosing.The ultimate roundup of the best pill organizers for travel ≫
Can You Take Vitamins and Supplements with Prescription Medicine?
Any prescription medication must always take priority over non-prescribed nutritional supplements. You must always adhere to your prescribed dosage schedule for prescription medication. If you have any doubts about how to take supplements alongside your prescription medication, you should check with your doctor, but here is some information provided for general knowledge and to stimulate discussion with your healthcare provider.
Retinoids, such as Accutane and Soriatane, are products that are chemically similar to vitamin A and used to treat acne and psoriasis respectively. The problem with retinoid prescription is the possibility of vitamin A toxicity. Toxicity could lead to nausea, vomiting, dizziness, blurred vision, and even poor muscle coordination.
Pregnant women should be the most vigilant as excessive vitamin A intake can be harmful for the baby. 
Pregnant women often experience acid reflux and could be prescribed medication for them. Drugs that help with heartburn (such as Omeprazole) are known to reduce the absorption of calcium, folic acid, vitamin C, and B12. This is easily remedied by either taking alternate forms of nutrients or by simply supplementing with the nutrient affected by the drug.
Warfarin is an anticoagulant or a drug that slows blood clotting. Taking supplements like Coenzyme Q10 and glucosamine have been known to reduce its anticoagulating properties. Minerals like iron, magnesium, and zinc are known to bind with warfarin which could lead to reduced absorption and metabolism. Taking vitamin K and warfarin together reduces warfarin’s effects. 
Those who are on Warfarin but wich to consume mineral supplements should take them two hours apart to be on the safe side.
Aspirin is taken to relieve pain, or to reduce fever and swelling. Taking aspirin could reduce the levels of iron, vitamin C, zinc, folic acid, and vitamin B12 in the body. Taking vitamin E with aspirin could lead to excessive bleeding. 
Statins are prescribed for patients with high cholesterol levels and for the management of symptoms that cause abnormal levels of cholesterol in the body. Niacin (B6) is known to help with high cholesterol levels and patients who self-medicate with Niacin and also take statins could lead to myopathies (muscle tissue disease) and rhabdomyolysis - the destruction of the muscle cells.
Metformin is a drug used to lower blood sugar levels, particularly in those with type 2 diabetes, or who are prediabetic. B12 and Folic acid levels in the body are reduced when taking metformin.
Calcium, magnesium, zinc, and iron could decrease the efficacy of common antibiotics such as fluoroquinolones and tetracyclines, and thyroid medication such as levothyroxine and bisphosphonates.
The suggested use is to avoid taking minerals and antibiotics or thyroid medications together and to separate ingestion by at least four hours.
Also known as Xenical and Alli, Orlistat is a drug used mainly for obesity management together with a low-calorie diet. Taking orlistat has been shown to decrease absorption of beta-carotene (for vitamin A) and vitamin E and reduce blood levels of vitamin A and D. 
Best Time to Take Vitamins: What does your doctor say?
No matter how rigorous the clinical research was that we derived our general advice from, the fact remains that we can only offer general information. The best advice you can get on the question of what is the best time of day to consume your vitamins, whether you should consume them all at once or space them out over the day, or any medication interaction concerns, is to ask your doctor for advice specific to your condition and history. The human body is a complex system of chemical processes, signals, and moving organs. There is no one cookie cutter way when it comes to taking vitamins and supplements especially when paired with medication.
Your doctors advice could be identical to what we laid out above, or they may recommend a completely different method or timing. Whichever the case, your doctor knows you better than we do and their decisions are much more credible given their experience and their knowledge of your physiology, and hopefully blood tests so they can offer precise advice on what vitamins and supplements would be best for you.
We prefer to source information from high-quality, academically rigorous sources. These are the references we used to develop this article:
- Lee JK, Jung SH, Lee SE, et al. Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo . Korean J Physiol Pharmacol. 2018;22(1):35-42.
- Grimble GK. Adverse gastrointestinal effects of arginine and related amino acids. J Nutr. 2007;137(6 Suppl 2):1693S-1701S.
- Sweetser S. Evaluating the patient with diarrhea: a case-based approach. Mayo Clin Proc. 2012;87(6):596-602.
- Keen MA, Hassan I. Vitamin E in dermatology. Indian Dermatol Online J. 2016;7(4):311-5.
- Albahrani AA, Greaves RF. Fat-Soluble Vitamins: Clinical Indications and Current Challenges for Chromatographic Measurement. Clin Biochem Rev. 2016;37(1):27-47.
- Olafsdottir AS, Wagner KH, Thorsdottir I, Elmadfa I. Fat-soluble vitamins in the maternal diet, influence of cod liver oil supplementation and impact of the maternal diet on human milk composition. Ann Nutr Metab. 2001;45(6):265-72.
- Institute of Medicine (US) Committee on Military Nutrition Research; Marriott BM, editor. Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations. Washington (DC): National Academies Press (US); 1993. 8, The Effect of Exercise and Heat on Vitamin Requirements. Available from: https://www.ncbi.nlm.nih.gov/books/NBK236216/
- Plum LM, Rink L, Haase H. The essential toxin: impact of zinc on human health. Int J Environ Res Public Health. 2010;7(4):1342-65.
- Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161-9.
- Lynch SR, Cook JD. Interaction of vitamin C and iron. Ann N Y Acad Sci. 1980;355:32-44.
- Vitamin A supplementation: who, when and how. Community Eye Health. 2013;26(84):71.
- Pastori D, Carnevale R, Cangemi R, et al. Vitamin E serum levels and bleeding risk in patients receiving oral anticoagulant therapy: a retrospective cohort study. J Am Heart Assoc. 2013;2(6):e000364.
- Mcduffie JR, Calis KA, Booth SL, Uwaifo GI, Yanovski JA. Effects of orlistat on fat-soluble vitamins in obese adolescents. Pharmacotherapy. 2002;22(7):814-22.
- Clean Eating Magazine. (2019). When is the Best Time to Take my Vitamins?. [online] Available at: https://www.cleaneatingmag.com/personalities/when-is-the-best-time-to-take-my-vitamins [Accessed 24 Jun. 2019].
- Drdavidwilliams.com. (2019). The Best Times to Take Your Vitamins?. [online] Available at: https://www.drdavidwilliams.com/when-to-take-vitamins [Accessed 24 Jun. 2019].
- Han B, Zhu FX, Shi C, Wu HL, Gu XH. Association between Serum Vitamin D Levels and Sleep Disturbance in Hemodialysis Patients. Nutrients. 2017;9(2):139. Published 2017 Feb 14. doi:10.3390/nu9020139