Do supplement “shots” like NAD+ actually work?

Take a walk down any main street in the U.S. and you’ll likely greet the same series of haunts — coffee shops, nail salons, restaurants, and grocery stores. Increasingly, however, you’ll also encounter niche wellness studios offering a menu of vitamin and nutrient shots and drips, including the buzzy coenzyme NAD+.

A better, more energetic you seems like it’s just a poke away. But here’s the bad news: Experts say that that’s not actually how vitamins, minerals, or other supplements work.

What makes IV vitamin therapy appealing

It’s not hard to figure out what’s drawing people to vitamin therapy via IVs and injections (either DIY or at spas and doctors’ offices). For one, supplements have much more bioavailability — i.e. they're easily absorbed and used by the body — in this format. There’s only so much of a given nutrient you can get through your diet or oral supplements. While the latter can work, you might not be able to get as much as what’s listed on the bottle, since only a percentage is bioavailable, or available for use by the body. (Everything from the exact type of micronutrient, your digestive system, and your genetics can influence this.)

But anything you get through an intravenous pathway — meaning it goes directly into your veins — is near or at 100% bioavailability, according to Dong Wook Kim, M.D., a board-certified internist at Massachusetts General Brigham who specializes in obesity medicine. Injections (which go into muscle or fat) have similar bioavailability, but they take a little longer to work, since they have to get through your tissue to make it into your bloodstream.

What’s inside those IVs and injections

There’s also some credibility to some of these nutrients. Take vitamin B12, which sometimes comes in “wellness shots,” meaning they’re injected via syringe into your muscle tissue. For people who lose weight via gastric bypass surgery, which can impact their ability to absorb B12, it really can be helpful. “People would report, ‘Oh, I got the B12 shot and I just felt so much more energy,’” says Lauri Wright, Ph.D., the president of the Academy of Nutrition and Dietetics and a professor at University of South Florida. But this is only the case for people with deficiencies, which is rare unless you’re vegan, since B12 is easy to find in animal foods, or you’re over 60, since we lose stomach acidity with age — which can also affect absorption.

Other things that impact your diet might impact how you absorb some nutrients, too. Right now, there's not much research exploring whether people taking GLP-1s are at a higher risk of nutrient deficiencies, as one 2024 review found. But it is common among bariatric surgery patients, who tend to be deficient in vitamins A, B12, D, E, and K, according to a recent meta-analysis.

Then there are buzzy, promising new supplements. Take NAD+, which seems to be making headlines on a regular basis. This molecule is naturally found in the body, where it has a ton of roles: It helps produce energy for cells, repairs DNA, and even seems to slow down the trajectory of aging. And while you can get NAD+ precursors (like tryptophan) through food, its levels still tend to drop with age. Low levels of NAD+ have been linked to metabolic diseases, like type 2 diabetes and non-alcoholic fatty liver disease. In fact, one review of the current data determined that increasing NAD+ has the potential to improve the cardiometabolic health, though some studies showed mixed findings.

However — and this is a big however — the authors added there's still a lack of data on the best form of it, the dosage, and the duration. In other words, there’s no clear consensus on how those of us in the real world can go about getting NAD+ in a way that delivers these benefits.

Why you might want to pass on wellness shots

All told, IV vitamin therapy doesn’t have much scientific evidence to back up its exciting claims. One small study in the Journal of Alternative Complementary Medicine found that patients with fibromyalgia reported an improvement in pain, depression, and quality of life after eight weeks of weekly infusions of Myers' Cocktail (a shorthand term for a vitamin B complex, including niacinamide, vitamin C, calcium, and magnesium, among other nutrients). However, the patients taking the placebo reported similar effects, making the true benefit — if there was any at all — impossible to measure.

GLP-1s and supplement injections

Then, there’s the fact that IV vitamin therapy or shots are being offered to people who are taking GLP-1s, often for hundreds of dollars by the telehealth company where they get their prescription medication. If you’re taking a GLP-1, which lowers your appetite, keeps you feeling full, and reduces cravings, you’re probably eating less. But “we need to optimize what they're eating so that they're getting a diet that is adequate in all the vitamins and minerals,” says Wright. “We have so many reports of people with muscle wasting after being on GLP-1s.” (Since people don’t eat enough protein, fat, and carbs, they actually lose muscle mass.) Plus, you might be eating less, but if what you’re eating is ultra-processed foods that aren’t nutrient dense, then you could be dealing with a vitamin and mineral deficiency, too.

That sounds like it could make someone taking a GLP-1 for weight loss a prime candidate for IV vitamin therapy — since, after all, they seem to have the best effect in people with actual deficiencies. But “you rarely see a nutrient deficiency by itself,” says Wright. “It usually goes hand-in-hand with other vitamins and minerals — for example, protein and zinc go hand in hand.” To put it another way, getting an infusion of a singular micronutrient won’t do much if you’re deficient in 12 of them. That’s something better solved by a registered dietitian than an injection.

And then there’s the risk of getting IV therapy in the first place. For one, “any time we're injecting something directly in the vessel, it puts someone at a higher risk of having infection,” says Juliana Simonetti, M.D., a board-certified internist at the University of Utah Health and co-director of its Comprehensive Weight Management Program.

There’s also no way to know what exactly you’re getting in an IV. “You don't know how they're mixing some of those vitamins or what they're injecting,” says Simonetti. It’s even more concerning if you get them alongside compounded semaglutide or tirzepatide, which she’s heard from patients firsthand. The injectors “mix them with B12 or other vitamins and give it to them as an injection,” she says. “I think that poses a significant risk because that has never been studied.”

The bottom line

Clearly, IV vitamin therapy may not be the cure-all it’s billed to be. But outside of the risk of infection, the biggest loss you’re looking at is from your wallet. “Many of these nutrients in an IV or a shot form are water-soluble [meaning they don’t get stored in the body], so you’re just going to be peeing out anything in excess,” says Wright. “You’re going to have extra money in your urine.”

If you suspect you might have a deficiency, you’re much better off checking in with your doctor than making an appointment for an IV drip. That way, they can find out what exactly is going on. For instance, if you’re low in vitamin B12 and your doc determines it to be a matter of absorption — versus you not getting it from, say, a vegetarian diet — then you might really need a shot of B12 so it can be absorbed, Wright explains. “As clinicians, we need to know the root cause of a vitamin B deficiency to just determine what our intervention is. Is it a pill or is it a shot?” she says.

Ultimately, it’s the same story with IV vitamin therapy as with supplements: Nothing beats the real deal. “Anytime someone can eat these micronutrients is much better,” says Simonetti.