How Long Does It Take For Vitamin Supplements To Work?

Many people buy vitamin supplements in the hope of improving how they feel. But most of us are unsure how long it actually takes for these products to have any impact on our body, or if they will have any impact at all!

Unfortunately, there is no straightforward answer to this commonly asked question.. 

That’s because vitamin absorption varies based on different factors. 

So in this post, we’ll identify these factors to help you work out when those vitamins might start kicking in. 

But first, here are five quick tips to get you started: 

- The time it takes for vitamins to absorb is different for everyone.

- You can’t rely on supplements to make up for eating a poor diet.

- Consult with your healthcare provider before taking supplements.

- Don’t worry if you can’t see any noticeable changes quickly.

- Choose supplements based on your personal health goals.

What factors can impact the effects of supplements?

Supplement dosage vs your deficiency levels

The time it takes for a vitamin to work depends on the dosage of the supplement vs how deficient you are before taking it. 

For example, if a person is extremely deficient in Vitamin D, they’ll need a higher supplement dosage to replenish themselves to a normal level. They might require a prescribed supplement or to increase their dosage by incorporating more than one supplement, such as our Vitamin D Tablets, Drinks and Sprays. 

But you don’t want to overdo it. It’s possible to overdose on vitamins which can cause some serious side effects. So it’s always a good idea to consult with your healthcare provider before regularly taking a new supplement. 

Supplement absorption rate

The time it takes for vitamins to work depends on the bioavailability of the vitamin. Calcium, for example, has a standard absorption rate between 25 and 35 percent, vitamin C is around 70-90% and zinc, copper and selenium can range between 30-80 percent. 

But take these numbers with a pinch of salt because a person's age, digestive system integrity, health, gender and deficiency levels will make the absorption rate different for each person. So if your body is highly deficient and absorbing 80 percent of the vitamin, it might only take a few days to feel a difference, whereas if your body is only absorbing 20 percent, it could take weeks. 

Water vs fat-soluble vitamins 

Fat-soluble vitamins deliver nutrients to the body differently from those that are water-soluble because they are stored and excreted from the body at different rates. 

Water-soluble vitamins such as B Vitamins and Vitamin C dissolve in water, which makes them easy to absorb into the tissues of our bodies and have a faster effect than fat-soluble vitamins. 

Fat-soluble vitamins, such as Vitamin A, D, E and K are absorbed through the small intestine and bound with proteins so they can be carried through the bloodstream before being stored in the body, therefore taking longer to have a noticeable effect. 

Nutritional paring 

How long it takes for vitamin supplements to work highly depends on the food you eat and other supplements you’re taking. 

For example, the relationship between Vitamin D and Calcium is important because Vitamin D helps your body to absorb calcium better. So if you are deficient in Vitamin D, you’re not going to be absorbing calcium as quickly or effectively as you could be. 

Your Diet

One of the biggest factors determining how long your supplements will take to work is your diet. 

You’ve got to remember that supplements are made to work alongside the food you eat, not replace the food. So if your diet is lacking, your vitamin absorption rate will not be as high as it could be because it lacks the necessary complementary nutrients. 

The best thing to do is to speak to a nutritionist and get some advice on how you can pair your supplements with an eating plan. This way, you’ll avoid making mistakes which might slow down the process of the vitamins working. 

Lifestyle and habits

Your lifestyle habits, such as regularly drinking alcohol and excessive smoking, can slow down or prevent your body from effectively absorbing vitamins.

As a result, your healthcare provider may recommend higher doses of certain vitamins to make up for those that are not being absorbed in your intestine, and to improve vitamin absorption naturally, aim to eliminate smoking and stick to no more than 14 units of alcohol a week. 

Health problems 

The rate of vitamin absorption can be a lot slower for people that suffer from health problems. For example, people with Chron’s disease commonly suffer with inflammation in the lower section of the small intestine which is where nutrient absorption takes place, making it difficult to absorb vitamins efficiently. 

What are signs that vitamins are working?

In some cases, it’s easy to tell when your vitamins are working. You’ll look and feel better pretty quickly, while for others, the signs are more subtle. But there are a few ways you can check whether vitamins are working. 

Test your vitamin levels

Going to your doctor for blood tests is the most accurate way to understand what vitamin deficiencies you may have. 

So before you start taking any vitamin supplements: 

  1. Get blood tests done to check for deficiencies by using a service such as Forth.
  2. Speak to your doctor & discuss the results of your blood test.
  3. Follow the guidance on supplementing from your doctor or speak to a nutritionist,
  4. Schedule a follow-up blood test after the regimen to see how deficiency levels have improved.

Record your symptoms using a 30-day journal

Starting a 30-day symptom journal can be a good idea to track the effectiveness of the vitamins: 

  1. Start your journal a week before starting a vitamin regimen, listing down all the symptoms you’re aware of. 
  2. Check-in on these symptoms at the same time each day and ask yourself: 
  • Do I feel any better today? 
  • Do I see any noticeable differences in the way I look?
  1. Continue this process for 30-days
  2. At the end of the period, compare your symptoms during the first few days with your final few days and write about how you felt at the beginning vs how you feel now. 

What should I do if my vitamins are not working?

Consult with your healthcare provider 

If you feel like your symptoms are not improving after 3 months, consult your healthcare provider who might prescribe a higher dose that’s not sold over the counter, or they might want to carry out some new tests to see what’s preventing your deficiency levels from improving. 

Consider your supplements 

At Get More Vits, our ambition is to provide vitamins in a range of formats to make them accessible to everyone, all our products are:

  • Sugar free
  • Low calorie
  • Contain natural flavours
  • Suitable for either vegetarians or vegans (depending on the product). 
  • Drinks are made from UK sourced spring water
  • Drinks, oral sprays and supplements are packed in the UK.

We pride ourselves on top customer service, so if there’s anything you need to know about our products, one of our lovely team will be happy to help! Please email us at: We’ll aim to respond to your enquires within 1-2 business days. 


If you’ve started taking a vitamin supplement, you’re probably wondering when the effects are going to start to kicking in. 

But the truth is, the time it takes really depends on these factors: 

  • The supplement dosage vs your deficiency levels 
  • The supplement absorption rate
  • Whether they are water vs fat-soluble vitamins 
  • Other supplements you’re taking 
  • The nutrients you’re getting in your diet 
  • Lifestyle choices and habits 
  • Health problems affecting absorption

During your vitamin regime, you’re probably going to be looking for signs to show you that the vitamins are doing their job. Sometimes, you’ll look and feel differently within a short space of time, but other times you’ll have to go the extra mile to find out. 

These are a few accurate ways to tell to see if the vitamins are working: 

  • Get some blood tests done to test your vitamin levels 
  • Record your symptoms in a journal each day for 30-days

If you’ve found that your symptoms are not improving after 3-months, then you should: 

  • Consult with your healthcare provider
  • Re-consider your supplements 

Want to continue learning about how vitamins work? Check out our other post where we explain what vitamins you should take for tiredness.


Becky Graham

Lead Nutritionist & Communications - Get More Vits

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