How Long Does It Take for Vitamins to Work?

how long does it take vitamins to work?

Have you just started taking (multi)vitamins to support your overall health or remedy a deficiency? You’ll inevitably wonder how long it takes for your vitamins to “kick in.” 

Unlike, say, Tylenol (which takes 20 to 45 minutes to start working depending on how you take it), you won’t necessarily notice a specific effect when your vitamins reach your system. Instead, you’re much more likely to notice gradual improvements as you keep up with your regimen. 

So, how long does it take supplements to work? That depends on the deeper question you’re asking — and you may be wondering about one of three things. How long does it take for the vitamins you take to reach your bloodstream? How long until you feel better? How long does it take to correct a specific deficiency?

Every question worth examining is worth examining in depth, so let’s take a look at all of those aspects! 

How Long Does It Take for Vitamins to Take Effect? The TLDR Version

  • Oral nutritional supplements can take minutes to days to reach your bloodstream. The time it takes your body to process supplements depends on the type of vitamins you take. 
  • Because vitamin supplements support your general health, no single “symptom” indicates that your vitamins are working. It is more likely that you’ll gradually feel better over time. 
  • Nutritional deficiencies generally take weeks to correct. The time it takes for your body to reach optimal levels depends on the severity of the deficiency and the treatment method. 
  • Being consistent about your supplement routine is the best way to make sure you get all the nutrients you need. 

How Long Does It Take for Supplements to Reach Your Bloodstream?

The speed at which a particular dose of vitamins, minerals, or other nutritional supplements reaches your bloodstream, and the percentage of the dose you took that successfully reaches its destination, is called bioavailability in medical terms. If this is what you were most curious about when you asked how long does it take for vitamins to work, the answer depends on the types of vitamins you take, and how you take them. 

How the Type of Vitamin You Take Impacts the Speed at Which It Reaches Your System

Most people who use multivitamins or specific vitamin supplements to support their general health take oral supplements. These oral supplements, which may come in the form of tablets, softgels (capsules), gummies, or effervescent tablets dissolved in water, have to pass through your digestive system just like any food or drinks you consume. 

The digestive process begins in the mouth, where enzymes help to break down the foods, drinks, and supplements you consume. It continues in the stomach. After supplements reach your intestines, where most of the nutrients are absorbed to be processed by your liver and kidneys, you can say that the dose has “kicked in.” This process can take anywhere from 30 minutes to several hours. 

Sublingual tablets, which are dissolved under the tongue, act significantly more quickly. In this case, the mucus membranes and blood vessels under the tongue act as a gateway that allows you to bypass the digestive system. Sublingual vitamin supplements remain an unusual way to get your extra vitamins, but they are rising in popularity. 

In cases of extreme vitamin or mineral deficiencies, doctors may recommend IV supplementation. An IV line allows the micronutrients to skip the line and get straight to your bloodstream, from which they can be transported to the cells. This process is almost instant. [1]

A Look at Water-Soluble vs Fat-Soluble Vitamins 

Vitamins can either be water-soluble or fat-soluble, and the category they fall into impacts the speed at which your body can absorb them. 

The fat-soluble vitamins, vitamins A, D, E, and K, dissolve in fat [2]. Supplementation is more effective if you take them with, or immediately after, eating foods containing healthy fats, like avocado, eggs, or cheese. These vitamins accumulate in your body’s fat stores, from where they can slowly be released. They take longer to process than water-soluble vitamins and can take hours to days to reach your cells. 

Water-soluble vitamins are vitamin C and all the B vitamins [3]. They dissolve in water, and because your body can’t store them long-term, you expel any excess through your urine. These vitamins start to work much more quickly, within minutes to hours. While water-soluble vitamins kick in faster, the fact that they’re not stored also means you have to take proactive steps to make sure you get enough every day. [4

How Timing Impacts the Absorption of Nutritional Supplements 

Your body absorbs water-soluble vitamins most quickly when you take them with water and on an empty stomach. On the other hand, fat-soluble vitamins dissolve in fat. They work more quickly when you take them with foods rich in healthy fats. 

People who choose single-vitamin supplements can improve the rate at which they’re absorbed quite effectively. If you take multivitamin supplements, which contain both fat-soluble and water-soluble vitamins as well as essential minerals, planning the best timing is more challenging. As a result, it may take slightly longer for all your nutrients to reach your system. 

How Long Does It Take to Correct a Nutritional Deficiency?

Have you been diagnosed with a specific nutritional deficiency? You may wonder how long it takes for vitamins to start working because you want to know when you’ll no longer be deficient. The answer depends on the specific nutrient and the extent of the deficiency. 

How Long Does It Take to Fix a Vitamin D Deficiency? 

Vitamin D deficiency is quite common in the United States, with over 40 percent of adults estimated to have at least a mild deficiency [5]. Fortunately, this deficiency can usually be corrected within as little as six to eight weeks [6], after which a maintenance dose can ensure that your vitamin D levels stay in the optimal range. 

How Long Does it Take to Treat an Iron Deficiency?

Iron deficiency can lead to anemia, which causes non-specific but very bothersome symptoms like overwhelming fatigue and shortness of breath. With the right level of supplementation, people can begin to feel better very quickly. As long as underlying causes besides a diet without enough iron are addressed, the deficiency can often be corrected within two weeks [7]. 

How Long Before Vitamin B12 Kicks In?

If you have a vitamin B12 deficiency, the time it takes to correct it depends on the cause. Vegans and strict vegetarians often run into this deficiency because they don’t get enough through their natural diets. However, people can also be deficient as a result of conditions that impact the absorption of this water-soluble vitamin, like celiac or Crohn’s disease or gastric bypass surgery. [8] Consistent supplementation is key to treatment, because your body doesn’t store vitamin B12. 

How Long Does it Take to Correct a Calcium Deficiency?

Calcium deficiencies are another common concern, especially among people who don’t eat dairy products. If you have a calcium deficiency, it’s important to be aware that supplements are available in two main forms. Calcium carbonate is budget-friendly and the most common choice. However, calcium citrate is much more readily absorbed, making it the faster way to treat a deficiency. [9]

Learn more: Vitamin C VS Calcium: Are They The Same?

The Bottom Line

The time it takes until you’re no longer deficient depends on many factors. They include how deficient you were at the beginning of the treatment protocol, how well your body absorbs the supplements you take, and how consistent you are about taking your supplements. The type of supplement you take also affects the success of the treatment. 

You may or may not notice any obvious physical changes, like feeling more energetic or having clearer, more vibrant-looking skin. The only fail-safe way to determine if your vitamin supplements are working is to have a blood test. 

Once your nutritional deficiency has been corrected and you have adequate levels of the vitamin or mineral in question, you can develop a long-term plan. This may include making changes to your diet or continuing with regular supplementation. 

How Long Do You Need to Take Vitamins Before You Feel Better? 

Have you recently decided to take better care of your health, and does that include taking a multivitamin supplement? Chances are that you’ve generally been feeling under the weather, and you think you can do a whole lot better. You may be stressed, moody, and tired. Your skin, nails, and hair make not look as healthy as they once did. 

When you ask how long does it take for multivitamins to start working, you probably simply want to know when you’ll feel better. Here, it’s key to remember that multivitamin supplements aren’t medications that treat a specific symptom or ailment. 

When you pop a Tylenol for a splitting headache, you’ll instantly know that it’s kicked in when the headache clears. Multivitamins, in contrast, ensure that you get close to the daily recommended intake of all essential vitamins and minerals. They support your general health. 

Some vitamins and minerals can make a tangible difference very quickly. Take vitamin C (a water-soluble vitamin), and it’s quite possible that you’ll experience a subjective energy boost within an hour. Similarly, you may start feeling better soon after you start a multivitamin regimen if you were a little low on iron. 

However, it’s more likely that you’ll notice an improvement much more gradually. One day, you may notice that you actually don’t feel tired anymore, that your mood has improved, and that your skin and hair look exceptionally healthy. 

Not to be cliché, but looking after yourself is a journey rather than a destination. You’ll look and feel your best when you give your body all the nutrients it needs every day, and in the right amounts, but it’s a gradual process. 

How Do You Start an Effective Vitamin Regimen That Meets Your Needs?

Our look at all the factors that impact what happens to your body when you start taking vitamins, and when your supplementation routine makes a tangible difference, has shown that this is a pretty complex topic. Fortunately, your supplement routine doesn’t have to be! Here’s how to get it right. 

Talk to Your Doctor

Most people who are excited to start taking vitamin supplements simply want to take steps to improve their overall health. Your primary care doctor is a valuable resource! Talk to your doctor for advice about the best supplements to take based on your lifestyle, diet, age, and medical history. Where necessary, your doctor will recommend testing for deficiencies before coming up with a plan. 

Consider Multivitamins vs Targeted Nutritional Supplements

Multivitamins offer a handy way to make sure you always have the nutritional support you need. Targeted vitamins, like vitamin C and calcium supplements, iron supplements, or vitamin D + A supplements, help you mitigate specific health risks you may have. Consider which ones are better for your situation. 

Establish an Easy Routine

Plenty of people buy nutritional supplements. Just as many diligently take them for a week or so, only to forget about that bottle at the back of the kitchen counter until the vitamins are past their expiration date. Don’t be one of them!

Taking vitamin supplements regularly is the key to reaping all the benefits they offer. Add taking your supplements to your to-do list, or set up reminders on your phone if you have to. As long as you’re consistent about your routine, taking supplements will soon become second nature. Guess what? No matter how long your vitamins take to start working, that’s the secret to making sure they keep working!

Unless you take multivitamin supplements, establishing a handy routine also allows you to get your timing right. Take water-soluble vitamins on an empty stomach, like before breakfast, and fat-soluble vitamins with meals that contain healthy fats. This approach gives your body the best chance to use all that goodness.