How Long Do Vitamins Stay in Your System? - A Complete Guide

  • By Performance Lab
  • 7 minute read
How Long Do Vitamins Stay in Your System? - A Complete Guide

We probably don’t need to remind you that consuming various vitamins and minerals is critical for good health.

While the majority of those nutrients come through diet, having a support system from a good multivitamin can also make a world of difference. But for a lot of people, how those nutrients are absorbed and metabolized still remains a big question mark.

The way your body absorbs vitamins and minerals plays a massive role in how effective the nutrient is going to be in the body and how safe it is to consume. Knowing both of these helps understand how long vitamins stay in the body and how often you should be supplementing them.

So, let’s talk about the difference between water-soluble and fat-soluble vitamins. We’re diving into what they are, how they’re absorbed, and what you should know about each of them to understand how long vitamins stay in your system.

Fat-Soluble vs. Water-Soluble Vitamins

The length of time a vitamin stays in the body depends on where it’s stored. Some vitamins are water-soluble and are excreted if not needed, whereas others are stored in fat and can remain in the body for quite some time.

Water-Soluble Vitamins

As the name suggests, the water-soluble vitamins are those that dissolve in water, which means they are more rapidly absorbed into tissues and are metabolized faster than their fat-soluble cousins.

Because they are dissolved in water, any excess of the water-soluble vitamins is excreted through urine and are not stored in the body. As a result, they need to be replenished daily through food or supplementation.

  • B1 (thiamine): Functions as a coenzyme in the pentose phosphate pathway, which is a key step involved in the synthesis of fatty acids, steroids, nucleic acids, as well as the aromatic amino acid precursors to several neurotransmitters and other bioactive compounds 1.
  • B2 (riboflavin): Two flavoprotein coenzymes are derived from riboflavin, FMN and FAD, both of which are critical rate-limiting factors in most cellular enzymatic processes, such as the synthesis, conversion, and recycling of niacin, folate, and vitamin B6; synthesis of all heme proteins; co-factors in the metabolism of essential fatty acids; absorption and utilization of iron; and regulating thyroid hormones 1.
  • B3 (niacin): A large number of processes and enzymes involved in several aspects of body function depend on niacin-derived nucleotides like nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP). Aside from supporting energy production, NAD and NADP are also involved in oxidative reactions, antioxidant protection, DNA metabolism and repair, cellular signaling events (via intracellular calcium), and conversion of folate to its tetrahydrofolate derivative 1.
  • B5 (pantothenic acid): Functions as a substrate for the synthesis of coenzyme A (CoA). It plays a significant role in oxidative metabolism, but is also involved in the synthesis of cholesterol, amino acids, phospholipids, and fatty acids 1. What’s more, B5 is also heavily involved in the synthesis of multiple neurotransmitters and steroid hormones.
  • B6 (pyridoxine): Apart from its role in the folate cycle, B6 is required for amino acid metabolism and serves as a rate-limiting cofactor in the synthesis of several neurotransmitters, including dopamine, serotonin, γ-aminobutyric acid (GABA), noradrenaline, and melatonin 1.
  • B7 (biotin): Plays a key role in supporting glucose metabolism and haemostasis, including regulating hepatic glucose uptake, gluconeogenesis (and lipogenesis), insulin receptor transcription, and pancreatic β-cell function 2. Deficiency of biotin is rare, but certain pathological conditions can reduce levels.
  • B9 (folate) + B12 (cobalamin): Many of the functions of folate and B12 are linked because of their complementary roles in the “folate” and “methionine” cycles. Low levels of B12 can result in a functional folate deficiency, as folate becomes trapped in the form of methyltetrahydrofolate. Proper function of the folate cycle is essential for the synthesis and regeneration of tetrahydrobiopterin, a cofactor for enzymes that convert amino acids to monoamine neurotransmitters (serotonin, melatonin, dopamine, noradrenaline, adrenaline) and nitric oxide 3, 4. They’re also heavily involved in red blood cell production and proper function of the nervous system.
  • Vitamin C: The classic role of vitamin C has been tied to immune function by supporting many cellular functions of both the innate and adaptive immune system, as well as supporting epithelial barrier function to protect the body against pathogens. It’s also a powerful antioxidant and serves as a cofactor for several biosynthetic and gene regulatory enzymes 5. Research suggests that the vitamin C pool is usually depleted in about 4 to 12 weeks if intake is reduced or stopped, with deficiency symptoms generally starting to manifest after eight weeks 6.

With all of that said, the exact time that water-soluble vitamins circulate in your body will depend on factors like age, nutrient status, diet, and the like.

However, most are depleted within 1-2 days, which means replenishing them daily to ensure sufficient levels if critical for optimal health and performance 7.

Fat-Soluble Vitamins

Again, as the name suggests, fat-soluble vitamins are a group of four vitamins that dissolve in, you guessed it—fat.

The fat-soluble vitamins are not absorbed directly into the bloodstream, but rather are absorbed into lacteals in the small intestine via chylomicrons and then transported through the lymphatic system before finally being released into the bloodstream 8. They are:

  • Vitamin A: Its major role is in supporting vision, but recent research suggests it’s also involved in embryonic stem cell differentiation and development, maintaining healthy structure and function of epithelial cells, and regulating macronutrient metabolism of carbohydrates, lipids, and proteins 9.
  • Vitamin D: A fat-soluble pro-hormone that plays significant roles in maintaining the health of bone, skin, cognition/mood, and the immune response 10. Low levels of vitamin D have been linked to a number of chronic health conditions.
  • Vitamin E: A powerful antioxidant metabolite and an essential dietary factor, vitamin E can be found in two naturally occurring groups: tocopherols and tocotrienols. The properties of vitamin E are largely related to its antioxidant functions, though it also has involvement in a variety of biological activities, including anti-oxidation, anti-proliferation and anti-inflammation 9.
  • Vitamin K: Vitamin K is heavily involved the blood clotting, as there are several vitamin K-dependent clotting factors, including prothrombin (factor II), factor VII, factor IX, and factor X 11. Insufficient vitamin K can lead to synthesis of nonfunctional clotting factors and cause hemorrhaging.

However, unlike the water-soluble vitamins, an excess of any fat-soluble vitamin doesn’t leave the body through fluids (urine, sweat, etc.), but rather is stored in the liver or adipose tissue for later use 12.

Studies suggest that although vitamin D is synthesized in the body and excessive intake is rare, vitamin D therapy, even in low quantities of 375 µg/kg for two weeks, can lead to toxicity 13. Similarly, vitamin E doses of 400 international units (IU) per day can increase risk of death.

That means that excessive intake of these vitamins can cause toxicity because they are stored anywhere from a few days to several months and levels will accumulate over time. As such, follow directions on supplement labels for safety.

Nutrient Considerations

One of the major benefits of water-soluble vitamins over fat-soluble ones is how they’re stored in the body, which dictates toxicity levels.

Because fat-soluble vitamins are stored in fat and can therefore build up in the body, you have to be mindful about dosages to prevent the potential for toxicity. As such, you should never “self-prescribe” and mega-dose on the fat-soluble vitamins.

However, with the water-soluble nutrients, there’s little chance that they will build up in the body, even in large amounts. Any excess of the B vitamins and vitamin C will exit the body when you pee.

But this also means that the water-soluble vitamins are used or excreted rather quickly, so you want to ensure you’re getting a consistent supply of them to prevent deficiencies and physiological impairments that can happen as a result.

What’s more, you also have to take into consideration nutrient bioavailability. Nutrient bioavailability in whole-food sources is generally pretty good, but when it comes to supplements, you never quite know what you’re getting.

Bioavailability typically refers to the proportion of an ingested nutrient that becomes available for use and storage in the body, but it also accounts for use and storage (retention) in body tissues 14.

For example, the fat-soluble vitamins require an adequate intake of dietary fat for absorption, whereas many vegetables require some sort of mechanical processing (chopping, mincing, etc.) to break down the cell wall and release the vitamins, especially B vitamins. When you can actually access the nutrient, your body can then use them.

How To Keep Vitamin Levels Up

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They’re vitamins and minerals bioengineered with cofactors that boost absorption and maximize benefits. You’re getting nutrients complexed with natural cofactors like probiotics, fiber, enzymes, and antioxidants designed to enhance their bioavailability and health-supportive activity so you don’t have to worry about whether you’re absorbing what you’re taking.

NutriGenesis® Multi for Men and Multi for Women build a strong nutritional foundation for healthy human performance across all body systems.

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  1. DO Kennedy. B Vitamins and the Brain: Mechanisms, Dose and Efficacy--A Review. Nutrients. 2016;8(2):68.
  2. M The malnutrition of obesity: micronutrient deficiencies that promote diabetes.  ISRN Endocrinol. 2012;2012:103472.
  3. SM Stahl. L-methylfolate: a vitamin for your monoamines.J Clin Psychiatry. 2008;69(9):1352-1353.
  4. SJ Moat, ZL Clarke, AK Madhavan, MJ Lewis, D Lang. Folic acid reverses endothelial dysfunction induced by inhibition of tetrahydrobiopterin biosynthesis.Eur J Pharmacol. 2006;530(3):250-258.
  5. AC Carr, S Vitamin C and Immune Function. Nutrients. 2017;9(11):1211.
  6. L Maxfield, JS Crane. Vitamin C Deficiency. (Updated 2021 Jul 18). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:
  7. K Shibata, C Sugita, M Sano, T Fukuwatari. Urinary excretion of B-group vitamins reflects the nutritional status of B-group vitamins in rats. J Nutr Sci. 2013;2:e12.
  8. D Nedra Karunaratne, D Asitha Surandika Siriwardhana, I Rangana Ariyarathna et al. 17 - Nutrient delivery through nanoencapsulation. In: Nutrient Delivery. Elsevier/Academic Press, an imprint of Elsevier; 2017:653-680.
  9. AA Albahrani, RF Fat-Soluble Vitamins: Clinical Indications and Current Challenges for Chromatographic Measurement. Clin Biochem Rev. 2016;37(1):27-47.
  10. LA Plum, HF Vitamin D, disease and therapeutic opportunities. Nat Rev Drug Discov. 2010;9(12):941-955.
  11. JW Vitamin K and human nutrition. J Am Diet Assoc. 1992;92(5):585-590.
  12. JF Landrier, J Marcotorchino, F Lipophilic micronutrients and adipose tissue biology. Nutrients. 2012;4(11):1622-1649.
  13. P Ravisankar, A Abhishekar Redd y,, B Nagalakshmi, O Sai Koushik, B Vijaya Kumar, P Sai Anvith. The Comprehensive Review on Fat Soluble Vitamins. IOSR Journal Of Pharmacy. 2015;5(11):12-28.
  14. A Melse-Boonstra. Bioavailability of Micronutrients From Nutrient-Dense Whole Foods: Zooming in on Dairy, Vegetables, and Fruits.  Front Nutr. 2020;7:101.