IV Infusion vs. IM Injection
“I keep seeing IV drips and vitamin shots everywhere. What is the real difference, and is the IV worth the extra time and money?”
This is one of my favorite questions, because the honest answer can save you both time and money. IV drips and intramuscular shots, the ones people call IM injections, often deliver the very same nutrients. NAD+, glutathione, B vitamins, vitamin C. The difference usually is not what is in them. It is how they get into you.
The simplest way to think about it
An IV puts the nutrient straight into your bloodstream through a vein. Nothing is lost along the way, so the full dose is available to your body right away. That is the appeal.
An IM injection puts the nutrient into muscle. From there it absorbs into the bloodstream more gradually over a period of hours. You generally receive a smaller dose, and your body takes it up more slowly.
There is also a third route you will hear about more and more, especially with the new at home kits. A subcutaneous injection goes into the fatty layer just under the skin. It is shallow, it uses a tiny needle, and it releases slowly, which is part of why it lends itself to home use.
None of these is better in the abstract. They are simply suited to different jobs.
When the IV is worth it
An IV makes the most sense when you want a larger dose, complete absorption, or a noticeable effect from a single visit. It is also the right choice for certain compounds that genuinely work better delivered this way.
NAD+ itself is the clearest example. To raise NAD+ meaningfully through the bloodstream, you need more than a small shot can carry, which is why it is given as an infusion. It also has to go in slowly. Pushed too fast, NAD+ can make you feel genuinely unwell, with flushing, nausea, cramping, or a tight chest. Delivered at the right pace and under supervision, those effects are avoidable. This is exactly why NAD+ is not something to rush, and not something to do without trained hands nearby.
The newer option, and why it still needs a physician
Here is where the field is moving. Instead of infusing NAD+ itself, some newer products deliver a precursor like Niagen, which is nicotinamide riboside, and let your body build NAD+ from it. Niagen now comes in prescription injectable forms, including an in clinic IV and an at home kit you inject just under the skin. Many people tolerate the precursor route more comfortably than a fast NAD+ drip.
The at home kits are convenient, and I understand the appeal. But notice what they still require. A prescription, a medical intake, and a licensed provider confirming it is appropriate for you. That is not red tape. Injecting anything carries real considerations, from sterile technique to your own health history, and some conditions call for extra caution. Convenience at your doorstep does not remove the need for a clinician who actually knows you. I would rather walk a patient through this than have them piece together the fine print from a packing slip.
And the same honesty from my last column applies. These delivery methods do raise NAD+. Whether injecting it delivers every longevity benefit people hope for, beyond what the oral form already offers, is still being studied.
When a shot is the smarter buy
An IM injection is often the better value for maintenance. If your goal is to top up a nutrient on a regular basis, a quick shot gets it done in minutes, costs less, and does not tie you to a chair for an hour. Glutathione and B12 are common examples that work well this way.
For a lot of people, the honest recommendation is a mix. An occasional IV when you want a fuller reset, and simple maintenance shots in between.
The questions that actually matter
Before you book anything, the useful questions are not IV or IM. They are these. What am I truly trying to achieve. What does my health history say I need. And what dose and route get me there most sensibly.
A good clinic should be able to answer all three, and should tell you when the cheaper option is the right one. I say no to the IV as often as I say yes, because the goal is the result, not the theater of the drip bag.
The bottom line
An IV gives you the full dose right away and is the right call for something like NAD+. An IM shot is quicker, easier on your schedule and your wallet, and often perfect for maintenance. A subcutaneous kit can be a comfortable middle path for a precursor like Niagen, as long as a physician has set it up with you. The best plan uses the right route for the right goal, rather than whatever happens to be trending.
If you would like, we can look at your goals together and sort out which belongs in your routine and which you can skip. That is the part I enjoy most.
Warmly, Dr. Alasio
