How Long Does It Take for Vitamins to Work?

So, you’ve decided to start supplementing with something new. Maybe it’s calcium to support bone density or maybe it’s methylfolate for mood. Maybe you’ve just switched to a new multivitamin formula. Now you’re paying attention to how your body feels every day, wondering when you will start to notice the benefits. How long does it take vitamins to work? 

That’s a bit of a trick question… 

Depending on the supplement you are taking and your health goals, you may feel a difference within minutes after taking a supplement. Other supplements may take weeks to take effect. You may also feel nothing at all, ever. Some nutritional deficiencies, and recoveries, may require a blood test to measure. 

A supplement has “worked” when your body has absorbed it, converted it to a usable form (if necessary), and your circulating levels for that nutrient are within the normal range. But this really requires us to define “working.” Many people define “working” as an observable change or experience. That can be misleading and forces us to change how we think. 

Supplements are not intended to treat any disease conditions or change the way you think or feel. However, your nutritional status (whether you are deficient/insufficient in certain nutrients) can impact both mental and physical health. Supplements can help to correct for a nutritional deficiency and maintain nutritional balance. You may notice that you feel better in your body once you have reached, and are maintaining, healthy nutrient levels. 

Taking a supplement one time, or even for a couple of weeks, may not be long enough to reach and maintain normal circulating levels. For example, one study found that it took participants six weeks to reach and maintain healthy vitamin D levels after starting a supplementation regimen. [1] 

If you have been taking a supplement regularly for two months or more and feel no difference in your mood, energy level, or general health, ask your healthcare practitioner for a blood test or other type of assessment. It can help to determine whether your supplement is being absorbed and circulating in your body efficiently. Some testing is an indirect measure of nutrient status. For example, plasma copper testing measures the total amount of copper in the blood, most of which is bound to ceruloplasmin, while ceruloplasmin testing assesses the level of the main copper-carrying protein produced by the liver. Interpreting both together provides a clearer picture of copper status, helping to differentiate between deficiency, toxicity, or a disorder. But remember, it is possible for a supplement to correct your deficiency without changing the way you feel.  

Where did you get your supplements? The grocery store or your healthcare practitioner? 

If your supplements were “a great deal” compared to other brands, they may contain cheaper, lower-quality ingredients, or ingredients that do not match the claims on the label. Many vitamins, minerals, and herbal extracts come in a range of forms and purity levels. As such, it is important to purchase supplements from reputable sources whom you trust. 

Would you rather spend less and see little to no result? Or spend slightly more and see the changes you hope for? If you don’t have a go-to brand you trust yet, ask an expert. For the purest supplements with the highest-quality ingredients, healthcare practitioners such as naturopathic physicians, Certified Nutrition Specialists and licensed nutritionists, and those with both conventional and integrative medicine training are a great sources of recommendations. 

You can also do some research yourself. You can look up the “most bioavailable form” of the nutrient you are interested in. The “bioavailability” of a nutrient is a measure of its efficiency in correcting a deficiency. The more bioavailable a supplement is, the more likely it is to be absorbed and raise circulating, active levels in the body. 

Make sure your supplement contains the most bioavailable forms of each nutrient. If it does not, the supplement you are taking may not be the best choice for fulfilling your nutritional needs. 

Do you have any health issues that could interfere with absorption? Crohn’s disease, chronic diarrhea, dysbiosis, leaky gut, and other issues of the gastrointestinal system can interfere with proper nutrient absorption. Talk to your healthcare practitioner if you think this may be the case. 

When are you taking your supplements? This is important because fat-soluble vitamins may be better absorbed when taken with foods, while water-soluble vitamins just need to be taken with liquid. Some supplements can cause nausea and other symptoms if taken on an empty stomach, so should always be taken after a meal. 

Are you taking medications that could interfere with nutrient absorption? You can ask your healthcare practitioner or pharmacist or look up these interactions by searching the name of your medication. 

Contraindication can happen between nutrients too. Some nutrients, like zinc and copper, or calcium and iron, compete for the same receptors for absorption. As such, you can better absorb these nutrients if you take them at different times of day from one another. 

Other nutrients are considered “synergistic” in their absorption, as in, they boost the absorption of activity of one another when taken together. For example, iron, zinc, and vitamins A, C, and E are a great combination. Zinc is required to transport vitamin A around the body [2], and iron is needed to convert beta-carotene into usable vitamin A (retinol). [3] Vitamin C helps your body absorb iron [4], and vitamin A helps your body absorb vitamin E. [5] Vitamin C and E are more effective in combination than when each is taken alone. [6] 

Then, at another time of day, try taking your calcium with vitamins D and K. Vitamin D is necessary for the absorption of calcium. Vitamin K helps to shuttle that calcium away from arteries and the heart to your bones (where we want it!). [7] 

On the other hand, water-soluble vitamins like B and C will not build up in otherwise healthy individuals. They typically can be taken long-term. The same is true for vitamins and minerals that are often lacking in the Western diet.  

While your healthcare practitioner is the best person to diagnose a magnesium or vitamin D deficiency, it is estimated that about 50% of the US population is magnesium deficient, and 35% are vitamin D deficient (50% insufficient). [8] As magnesium is required for the metabolism of vitamin D, it is important to have healthy levels of both in the circulation. It is suggested that very high doses of vitamin D should be monitored to identify excess intake. 

Multivitamin/mineral formulas are designed with long-term use in mind. Taking a multivitamin/mineral supplement fills in nutritional gaps created by diet with variations. Taking a multivitamin on a regular schedule, daily, is a great way to keep these levels even and consistent even when the foods you eat change. 

One fantastic way to make sure you never miss a supplement is to sign up for a subscription, or auto-delivery service. Rather than keeping track of how many supplements you have left in the bottle, some brands offer a subscription option at checkout. 

If you have a bottle with 30 capsules, and you take one per day, you can have a bottle delivered automatically once a month. Ninety capsules and you take one per day? Schedule your delivery once every three months. Plus, you can save money on every delivery once you have subscribed. 

We already have so much to keep track of these days, “remember to order supplements” can be one less item on your to-do list. No gimmicks, just a helpful feature to make sure you never miss a supplement because you forgot to make an order. 

Disclaimer:
The information provided is for educational purposes only. Consult your physician or healthcare practitioner if you have specific questions before instituting any changes in your daily lifestyle including changes in diet, exercise, and supplement use.

Laura Lewis is a clinical researcher and science communicator with a Master of Science degree and a background in nutrition science and integrative health. She brings a decade of experience translating complex clinical data into accessible insights for healthcare practitioners and patients alike.

Laura has contributed to educational programming and strategic content development across the integrative and functional medicine space. Her strengths lie in evidence synthesis, practitioner engagement, and crafting communications that bridge the gap between scientific rigor and real-world application. At ARG, Laura supports clinical content development and educational initiatives that elevate practitioner confidence and product credibility.