Seeing Red: Do B12 Injections Work?

Sometimes it seems like everyone is fighting fatigue with vitamin B12 injections. But do they do any good?

Almost a year after the birth of my second child, my body felt broken. Every virus my kids had, I caught, too, and sleep deprivation, lack of exercise, and a rotten diet—the trifecta experienced by all new parents—were taking their toll. With my immune system in the same place as my mood (severely depleted) I wandered the aisles of Whole Foods and filled my cart with promising-sounding nutritional supplements: Cat’s Claw Defense Complex, Rescue Remedy, Wellness Formula. As I swiped my credit card to pay the bill, it occurred to me that for that much money I could have gone to a specialist.

Two weeks later, still feeling sluggish, I went to see my internist, who gave me a full physical, some homeopathic cures of her own, and an injection of vitamin B12 in my butt. The effect seemed immediate. Driving home, I felt a faint electric buzz of energy, the sort of oomph an afternoon espresso can provide. But there was none of the edge I get with caffeine; the buzz stayed steady, a hum of vitality that took me through the rest of the day and into the evening until I powered down with ease, slipping into slumber like a lion with a belly full of prey. The next day I continued to feel great. I’d say the effect lasted about 24 hours.

B12 shots are massive doses of the water-soluble vitamin—found in foods such as shellfish, beef liver, and fortified breakfast cereals—that is essential for neurological function, red blood cell formation, and DNA synthesis. Most people get the recommended dietary allowance of B12 (2.4 micrograms for adults, more for pregnant or lactating women and the elderly) through their daily intake of food. The typical injection, a vial of neon red liquid that resembles the dyed sugar water I put in my hummingbird feeder, contains 1,000 micrograms of B12, or in excess of 400 times more than what the average person requires. Proponents of B12 shots claim they turbocharge the metabolism (read: make you thinner), strengthen the immune system, and help cure fatigue, insomnia, even depression.

But do they? Ever since B12 emerged in the ’60s, when it was often mixed with amphetamines, and then later, when everyone from Madonna to Margaret Thatcher was trying it out, its efficacy has been the subject of debate. Mostly the argument pits Western medical practitioners against those who favor homeopathic and alternative treatments. My internist, Sabena Toor, straddles that divide. A third-generation physician who has also studied ayurvedic medicine, she calls B12 injections “an integral part” of her practice. Toor says her patients rave about their benefits, and she herself relies on them when she needs a boost, like when she’s worn out from a long airplane flight or “when I haven’t been good—you can’t do everything perfectly all the time, and B12 helps.” For me she recommended shots every two weeks.


Nevertheless there is no medical evidence that injections of vitamin B12 promote health in anyone other than those who are suffering from a B12 deficiency. “It’s an old wives’ tale,” says David Heber, M.D., director of UCLA’s Center for Human Nutrition. According to Heber, the only reason to take extra B12—and it doesn’t have to be injected; it can be taken as a pill or under the tongue—is when there is a deficiency that can be caused by pernicious anemia, celiac or Crohn’s disease, or weight loss procedures such as gastric bypass surgery, which interferes with the body’s ability to extract vitamins from food. In addition, as we age, our ability to absorb B12 from food declines, which puts the elderly at higher risk of deficiency. According to The New York Times in 2011, as many as 30 percent of older adults may lack sufficient B12. That same year the National Institutes of Health indicated that 1.5 percent to 15 percent of the nation is deficient.

For that group a hit of B12 can seem like a magical cure. “As is true for many of the vitamins discovered in the early 20th century, the effects of B12 seemed miraculous,” Heber explains. “You had people suffering from anemia, and suddenly they were healed.” Heber remembers being at a hospital in Bishop, California, when a wheelchair-bound man who had undergone gastric bypass surgery came in complaining of fatigue. Shortly after receiving a B12 injection, he got up and walked. “Seeing that sort of experience, even for a doctor, stays with you,” says Heber.

If you’re wondering, as I did, how to find out whether you’re B12 deficient, don’t waste your time. The test isn’t covered by most insurance companies. And since having too much B12 isn’t harmful (the body simply excretes the excess), it’s easier and cheaper to just get a shot (B12 injectables cost $14 apiece if bought online or $20 to $70 at a spa or doctor’s office).

So how to explain all the anecdotal evidence that seems to prove B12 works for so many? Some research indicates that elevated doses of B vitamins improve sensory-motor control. A 1989 study published in the International Journal for Vitamin and Nutrition Research revealed that marksmen who received vitamin B shots improved their firing accuracy. Then there’s the placebo effect. Even if the extra vitamins themselves aren’t having a physiological impact, the ritual of getting a shot from a trained professional can help quell anxiety or provide a better sense of control.

“Sometimes just seeing an objective third party and unloading your issues makes you feel better,” says film director Peyton Reed, who once had a doctor give him a B12 shot on set when he was on the cusp of getting a cold—an injection that he believes kept the cold at bay. (Hollywood seems to love B12 shots; Sony Pictures keeps a physician and licensed nurses on its lot full-time who can administer them.) “Call it the Flintstones Vitamin Effect,” Reed says. “I take a multivitamin every day to stay healthy, but do I have empirical evidence it works? No, only that my urine is more yellow. Still, I feel better because I feel like I’ve done something positive for my body. That’s how I felt about the B12 shot.”

Humans aren’t the only ones getting their fix. When filmmaker Laura Nix’s elderly cat had an intestinal blockage, her vet suggested a B12 injection along with an enema. “Suddenly the old lady had pep in her step,” Nix reports. “Usually after a trip to the vet, she’d pass out asleep, but she was playing like a little kitten.” Nix credits the shot, not the enema. But ultimately it probably doesn’t matter: The cat got friskier, Reed didn’t catch a cold, and I had more energy—all after receiving big red shots. Whether we go to a doctor with decades of medical expertise or stroll the aisles of a health food store, in the end we’re paying to feel better—hopefully we are better, too—and to alleviate our illnesses, real or imagined, with a pill, a shot, or a poop. If you think a B12 shot will give you more stamina, help you lose weight, or make nodding off a bit easier at night—well, you might be right.

So why not play a little trickery on the body by curing what maladies you can with a harmless treatment that may, or may not, benefit you tremendously? Who cares if it’s all in your mind? My mother taught me to rub Vicks VapoRub on my feet when I felt I was catching a cold and to put a key down my back to stop nosebleeds; I’ll swear to the effectiveness of both even without a lick of scientific evidence. Which is why I’m adding another old wives’ tale to the list. Bottoms up—it’s time for my next shot.