How Long Does It Take for Vitamins to Work?

How long does it take for vitamins to work
Reading Time: 5 minutes

So, you’ve decided to start supplementing with something new. Maybe it’s calcium because you’re concerned with bone density, maybe it’s methylfolate because you’ve heard of its mood-boosting capabilities. 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 the health issue you are hoping to address, 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.

Is My Supplement Working?

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.

Supplements are not meant 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, a 2019 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 doctor for a blood test. It can help to determine whether your supplement is being absorbed and circulating in your body efficiently. It is possible for a supplement to correct your deficiency without changing the way you feel.

Why Isn’t My Supplement Working?

If a blood test shows your supplement is not helping to correct a deficiency or insufficiency, you may be having issues with absorption. Below are some reasons why this may be happening.

Quality vs. Savings ($)

Where did you get your supplements? The grocery store or your doctor?

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 only purchase supplements from reputable dealers 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, naturopathic physicians are a great source of recommendations.

Bioavailability and Purity

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.

Synthetic fillers, anti-caking agents, coatings, and other elements can also interfere with absorption. Look for a brand that states outright that they do not add these ingredients and check the ingredient list for purity.

What Makes You Unique?

Do you have any health issues that could be interfering 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 doctor 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 be interfering with nutrient absorption? You can ask your doctor or pharmacist, or look up these interactions by searching the name of your medication.

Synergy vs. Contraindication

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 (where it can cause problems) to your bones (where we want it!) [7].

Short-Term or Long-Term Supplementation?

Just like eating a single salad does not negate the importance of a daily balanced diet, taking one capsule of a nutritional supplement cannot improve your health in a meaningful way. Using a supplement to boost your nutritional health takes time, regularity, and patience. Once you have found the right time of day for your supplement (e.g. morning for energy-boosting B vitamins, bedtime for relaxing with magnesium), make taking the supplement a part of your routine. Expect it to stay a part of your routine unless your doctor has recommended otherwise.


Yes, there are some supplements designed for short-term use. Immune-boosting supplements that contain high potencies of zinc and vitamin A, for example, may be helpful in supporting your body’s natural efforts to knock out a bug. When you are well again, you probably don’t want to keep taking high potencies of these nutrients, as they can build up in your system.


On the other hand, water-soluble vitamins like B and C will not build up in otherwise healthy individuals. If they give you an energy boost or take some pressure off of your diet to provide these nutrients, they can be taken long-term. The same is true for vitamins and minerals that are typically lacking in the Western diet. Vitamin D and magnesium are two highly under-publicized deficiency epidemics.

While your doctor 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.

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.

Consider a Supplement Subscription

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 jar, some reputable brands, like Metabolic Maintenance, offer a subscription option at checkout.

If you have a bottle with 30 capsules, and you take 1 a day, you can have a bottle delivered automatically once a month. Ninety capsules? Schedule your delivery once every three months.

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.

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