Do Multivitamins Work? Why One-a-Day Tablets and Gummy Vitamins Fall Short
Isn’t a good multivitamin enough? That came up on a Reset Room call, right after a question about gummies, and the two belong together, because the answer to both is about delivery rather than ingredients.
Do multivitamins work?
The idea works. The one-a-day tablet usually does not. To fit every vitamin and mineral on the label into a single tablet, the manufacturer has to compress the whole lot so hard that your stomach acid struggles to break it down, so a share of what you paid for passes through you unused. A multi split across capsules and taken twice a day is a different product, and that one does what it says.
Think about what goes into the one-a-day business. The calcium, the magnesium, the B vitamins, iron, zinc, every mineral they can list. Forget the energy that food gives you; just the vitamins and minerals. A big machine condenses all of it into one tablet, and that tablet is so compact and so dense that it is very difficult for your stomach to take apart. You swallow the horse pill, and a good part of it stays a horse pill. Independent testing bears this out: ConsumerLab, which buys supplements off the shelf and tests them, regularly finds multivitamins that do not contain what the label claims or do not break apart within the time the standards require.
So the question is not whether to take a multi. It is whether the one you are taking can be digested. The formula I use with my own patients is two capsules twice a day, four in total, with gut-support and mitochondrial-support ingredients built in alongside the vitamins and minerals. It is definitely not one a day. But you get all of it, and it gets into you.
What makes a multivitamin actually absorb?
- Capsules rather than a compressed tablet. A capsule opens in the stomach; a dense tablet has to be dissolved.
- The dose split across the day, with food. Your gut can only take up so much of some minerals at once.
- Fat with the fat-soluble ones. Vitamins A, D, E and K need fat in the meal to be absorbed; more on that below.
- Your stomach acid intact. If you have been taking an acid blocker for years, you absorb less of several nutrients that matter, magnesium, iron and B12 among them, and a capsule will not fix that on its own. I have written about why reflux is so often a low-acid problem.
Are gummy vitamins effective?
As a multivitamin, no. As a way to take one nutrient, sometimes. Gummies are popular because they taste good, they are easy to chew, and they give you something to do with your mouth. The problem is what it takes to make a vitamin taste like candy.
To be palatable, a gummy carries sugar, or an artificial sweetener in place of it. It also holds far fewer nutrients than a tablet, because you cannot pack much into a gummy, and iron is usually left out altogether because it reacts with the other ingredients and ruins the taste. Then there is stability: when ConsumerLab tested gummy multivitamins in 2023, every one it selected missed its label claims in one direction or the other. A brand going round social media right now sells a six-gummy snack pack claiming sixty-plus vitamins, minerals and fibre, and better digestion because it is a gummy. I do not see a reason to get your fibre from a gummy. If you want fibre, eat an apple.
Where a gummy can make sense is a single nutrient. One B vitamin, or creatine, delivered in a gummy by a company that is not falling over itself to make it taste like dessert, can be perfectly useful for someone who cannot swallow a pill. As a replacement for a real multivitamin, it is not.
Should you take B12 and vitamin D under the tongue?
You can, and for B12 it works as well as swallowing it. A sublingual tablet dissolves through the lining of your mouth and the top of your throat, so the vitamin gets in without passing through the stomach. I like sublingual B12 for that reason, and it is a sensible choice for anyone on acid blockers or with absorption trouble in the gut. For the record, when researchers in Israel compared 500 micrograms of B12 sublingually against the same dose swallowed, for four weeks, blood levels rose by the same amount in both groups. Either route corrects a deficiency. Pick the one you will actually take.
Vitamin D is a little different. A capsule is fine, but take it with fat. Vitamin D is fat-soluble, and fat in the meal triggers the bile that carries it in. In a 2015 trial, older adults who took vitamin D with a meal containing fat absorbed about a third more than those who took it with a fat-free meal. A teaspoon of olive oil or a tablespoon of yogurt alongside the capsule is enough.
Do you need collagen, greens powder or astaxanthin?
Maybe. These are the trending supplements, and they may well be good for you. The question I ask is whether you need them. My expertise is not supplements in general; it is what you need to take to move your health and your blood chemistry. Walk into any nutrition store and there are thousands of bottles, and if you took all of them maybe you would be the healthiest person in the world. I do not think so. I let my blood work dictate what I take.
In practice that gives me two categories. There are the things I take forever, which I think of as more like food than medicine, and the blood work decides those. And there are the things I take medicinally, for a season. If I pick up an injury at the gym, I increase my turmeric. If I have spent a summer eating too much ice cream and I can feel the insulin resistance creeping back, I use berberine until it is gone. Then I stop. Neither is a forever supplement, and neither goes on the list without a reason.
My expertise is not on nutritional supplements as much as it is on what I need to take to have an impact on my health and my blood chemistry.
How do you know what you actually need?
Blood work, and more often than once a year. B12 and vitamin D levels can change in a few months, which is the whole case for retesting twice a year instead of guessing your way through twelve months of a dose you may not need. I have set out the reasoning in how often should you get blood work done. The short version: a multivitamin that digests, in capsules, twice a day, covers the floor. Blood work tells you what to add on top, and when to stop.
References
- Sharabi, A., Cohen, E., Sulkes, J., & Garty, M. (2003). Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route. British Journal of Clinical Pharmacology, 56(6), 635–638. https://doi.org/10.1046/j.1365-2125.2003.01907.x
- Dawson-Hughes, B., Harris, S. S., Lichtenstein, A. H., Dolnikowski, G., Palermo, N. J., & Rasmussen, H. (2015). Dietary fat increases vitamin D-3 absorption. Journal of the Academy of Nutrition and Dietetics, 115(2), 225–230. https://doi.org/10.1016/j.jand.2014.09.014
