B12 Supplements and IVs Promise an Energy Boost. Here's What the Science Says

Yahoo

21-07-2025

B12, a vitamin naturally found in animal products, has become the internet's favorite solution to low energy, fatigue, and overall sluggishness. It's long made an appearance in multivitamins and standalone pills—but these days, its footprint seems to be ballooning. Energy drinks and shots are juiced up with the ingredient, as are IV drips promising things like vitality and hangover relief. And of course, a growing market of run-of-the-mill B12 tablets and gummies tout similar claims, suggesting the vitamin can give you an instant energy lift. But as with most supplements, marketing can be deceiving, and the truth about B12 isn't quite so 'easy pick-me-up' as you might (desperately) want to believe.
B12 is indeed a critical vitamin to consume. It plays a key role in forming red blood cells (which shuttle oxygen to your organs) and helps convert food into energy, so it makes sense why people might associate it with getting a boost, Gary Soffer, MD, director of the Integrative Medicine Program at Yale School of Medicine, tells SELF. It also helps create new DNA molecules (which are necessary to repair cells and form new ones) and maintain healthy nerves (hence why B12 deficiency is linked with neuropathy and even cognitive decline). Plus, the body can't make it, so we have to get it from outside sources, like meat, fish, eggs, and dairy items.
But at the same time, we don't need much B12 to reap its benefits—the recommended amount for adults is 2.4 micrograms daily, which most people in the US typically hit with food. So, are there benefits to taking a supplemental form of it? And how can you tell if you might actually be B12 deficient? Read on for everything you need to know about taking B12 and when, if ever, it may be something your doctor recommends.
Spoiler alert: There's no evidence that suggests loading up on B12 will give you energy if you're not deficient.
It's true that a lack of vitamin B12 in your system—less than around 150 picograms per milliliter of blood—could manifest as fatigue or weakness. (Though it's worth noting, B12 deficiency doesn't always trigger symptoms.) Without enough B12, you could wind up with larger-than-usual red blood cells that don't effectively transport oxygen to your organs, which is a form of anemia. Plus, low B12 levels could interfere with your body's typical process for churning out energy from food, which may contribute to lethargy. And it can eventually diminish the protective covering on your nerves, leading to neurological symptoms like numbness and tingling in your hands and feet, and mood changes. So if your doctor determines that you have a B12 deficiency, taking a B12 supplement could restore your energy and resolve other related symptoms. However, as few as 6% of people in the US under age 60 have a B12 deficiency.
If you're like the majority of the population that is not substantially missing out on B12, consuming more than the recommended daily value isn't going to make any difference—no matter how fatigued you may be. After all, there are a bunch of non-B12-related causes for tiredness, ranging from stress, dehydration, and poor sleep habits to medical conditions like depression and hypothyroidism. 'It's the same reason why taking more iron when you're not iron-deficient isn't going to increase your energy, either,' Elisabeth Fowlie Mock, MD, MPH, a family physician in Bangor, Maine, and a member of the board of directors of the American Academy of Family Physicians, tells SELF. Not to mention, your body will just flush out any extra B12 in your pee. 'It works like a gas tank,' Dr. Soffer explains, 'so if you take more [than it needs], it'll just spill over.'
Any boost you might feel from popping a B12 supplement is generally a placebo. When it comes to shots and energy drinks laden with the stuff, there's a greater chance that you're feeling buzzy in response to other ingredients like caffeine and sugar. And the instant refreshment of an IV drip is often tied simply to the rush of hydration.
B12 deficiency is pretty rare, though a few GI disorders could make it more likely.
Most people in the US get plenty of B12 via their diet. (A single serving of beef or Greek yogurt, or two large eggs can get you about halfway to the recommended daily value, and one serving of salmon or canned tuna is enough to surpass it.) So doctors don't generally suspect a B12 deficiency (at least, not off the bat) if someone comes to them with malaise or fatigue, Dr. Mock says, nor do they routinely check B12 levels with a blood test. That said, your doctor may be suspicious of deficiency if you report not only tiredness but also the neurological or cognitive symptoms noted above. Same goes if you're experiencing other symptoms of anemia like shortness of breath, dizziness, pale skin, and a fast heartbeat. Iron deficiency is a more likely culprit there, Dr. Mock says, but your doctor may still check your B12 level to be safe.
The other scenario that may prompt them to assess B12 for low energy is if you have a risk factor for deficiency. A big one is being vegetarian or vegan. After all, B12 only occurs naturally in animal products. While there are veg-friendly foods that are fortified with B12, like some cereals, plant milks, and nutritional yeast, it's still easier to fall short if you're in this camp, Dr. Soffer notes.
Because of the way B12 is absorbed via stomach acids, deficiency is also more common in those who have GI-related conditions. In particular, people who take common heartburn meds called proton pump inhibitors (that reduce stomach acid production) may be at higher risk, as are older adults, who just tend to have less stomach acid. (The number of people with B12 deficiency jumps from 6% to nearly 20% for the 60-plus population.)
All types of B12, whether in animal sources or fortified foods, also need to sync up in the stomach with a protein called intrinsic factor in order to be fully absorbed. And some people might not make enough of this protein for that process to work. This can happen to those with a condition called pernicious anemia, as well as folks with certain GI disorders (like celiac or Crohn's) or alcohol use disorder (AUD), and those who've had bariatric surgery or another procedure that involved removing some or all of their stomach. So if you fall in one of these groups, there's reason to suspect you might be dealing with a bonafide B12 deficiency. (But if that's you, there's also a good chance you're already aware of your potential for nutrient deficiencies, Dr. Mock points out, and feeling fatigued will be far from your only symptom.)
If you *do* have a B12 deficiency, a supplement isn't always the solution.
In the particular cases above where a B12 deficiency could be on the table, your doctor may first run some routine bloodwork. This includes a measure of the average size of your red blood cells called mean corpuscular volume (MCV). A high MCV could prompt them to check your B12 level with an additional blood test, Dr. Mock says. (A normal MCV, by contrast, is reassurance that B12 probably isn't the issue, she adds.)
If your B12 is indeed below the norm, it's important to work with your doctor to figure out how to raise your level. You might be able to do this via food, perhaps by eating more B12-fortified items. Experts agree, it's best to consume any vitamins and minerals via food because your body can use them more easily than in supplement form. Not to mention, the supplement industry is a hazy, unregulated one. These OTC products don't have to go through the same rigorous FDA approval process as medications, so it can be tough to know if you're getting what's on the label. That said, if your doctor does suggest taking an oral supplement to close the gap, they can steer you toward a reputable brand that's been third-party tested. They can also advise on the ideal dose and format (pill or under-the-tongue lozenge), and whether it makes sense for you to take a B-complex product (including a mix of B vitamins) or a standalone B12 supplement.
Worth noting: In cases of deficiency caused by a GI or health condition that hinders absorption, just downing more B12 in supplement form might not solve the problem. After all, B12 in pills (or souped-up energy drinks) still needs to connect with intrinsic factor in the gut to get absorbed. That's why, in these specific situations, your doctor might recommend supplementing B12 via prescription injections or nasal gels, which bypass the GI route completely and go straight into your bloodstream.
Bottom line: Most people with fatigue aren't lacking B12, so supplements aren't the solution.
Low B12 is an uncommon reason for feeling tired. Chances are, if you have a deficiency, it coincides with one of the specific lifestyle or health-related situations above. 'Someone who has no known risk factors who truly has a vitamin B12 deficiency is a needle in a haystack,' Dr. Mock says. For most people, taking in extra B12 will just give you B12-rich pee…rather than any noticeable boost.
So, what to do if you're feeling sapped and craving energy? Dr. Mock recommends turning to some tried-and-true lifestyle changes, like cutting down on screen time, getting outside in nature more often, fitting in daily movement (at least a few hours before bedtime), and eating a balanced diet that includes breakfast. These tips may not be as sexy as the latest B12-infused drip, drink, or pill, but they're bound to help you get better sleep at night and feel more rested and ready-to-go come daytime. If you try out a few of these and still can't seem to escape the drag of constant fatigue? It's worth seeing your doctor. Low B12 may not be the root cause—but they can certainly help you figure out if a medical condition might be lurking, and what you can do to get the pep back in your step.
Related:
3 Things to Do When You're So, So Tired But Sleeping More Isn't an Option
How to Feel Less Depleted by the End of the Workweek
6 Less Obvious Signs of Burnout You Should Definitely Pay Attention To
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Originally Appeared on Self