The Truth About Intravenous Dietary Supplements

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Did you know that some private clinics offer intravenous drips containing dozens of dietary supplements? It is implied that by delivering various natural compounds like vitamins directly to the blood, these treatments are more effective than taking the same supplements orally, and can fix anything from ageing skin to anxiety and depression. But does science actually back this up? Let’s take a closer look.

Why use an IV drip?

An IV drip is a way of delivering a fluid directly into a person’s vein. There are two main reasons to deliver a compound intravenously. The first is if the recipient is for whatever reason unable to receive the compound orally, which is not really relevant to these kinds of clinics.

The second is to bypass the gut. When you consume a bioactive compound, it must first be absorbed into the blood via the gut. The circulatory system then delivers the compound to the rest of the body. However, many supplements are broken down by gut bacteria or by the hostile conditions of the gut before they get a chance to be absorbed into the blood. Even then, the absorption of the surviving supplement won’t be 100%. The proportion of the dose of any compound that actually reaches the blood is called bioavailability. For example, vitamin D has been estimated to have a bioavailability of between 55% and 99%. This means that if you take 10 micrograms of vitamin D, as little as 5.5 micrograms might actually be available for use by your body. This variation comes from differences between individuals – things like age, gut health, diet and even the time of day.

While many supplements have reasonably good bioavailability, others are simply too unstable to survive in the gut. Take for example NAD+, the level of which falls as we age. NAD+ is involved in many processes through to protect against ageing, and is under investigation as a potential anti-ageing supplement. NAD+ is not very stable, and degrades in alkaline and acidic conditions found within the gut. If you were to take NAD+ orally, the amount reaching your blood would be very small. This is why NAD+ is often taken in the form of a more stable precursor molecule, such as NR or NMN, in the hope that it will be absorbed as such in the gut and later converted into NAD+ by the cells that need it.

With IV delivery, compounds are delivered directly to the blood, so the proportion that reaches the target tissues is much higher. Compounds also reach the target much faster – no need to wait for them to reach the gut and then be absorbed. This makes IV delivery faster and more efficient than taking a drug orally, and also allows certain compounds that would not survive the gut to be delivered directly to the blood. This eliminates any guesswork related to how gut microbes might metabolise the supplement.

Why NOT use an IV drip

So, it’s pretty clear why an IV drip might be beneficial for a patient in a hospital setting. They give physicians better control over the dose of a drug and ensure that the drug gets into the blood quickly, which is particularly important if the patient is in a critical condition. There are some medical emergencies or severe deficiencies in which nutrients and micronutrients like vitamins could be given intravenously. But what does the average, healthy person stand to gain from having something like a vitamin or amino acid supplement delivered directly into their veins?

The short answer is: probably not a lot, but it really depends exactly what is being delivered. Let’s take a look at the proposed uses and why they might not make as much sense as it initially seems.

Case 1: To improve the effectiveness of supplements usually taken orally

Based on some of the supplements that commercial services are offering and how they are marketed, there seems to be an implication that delivering a given supplement intravenously is always inherently better than taking it orally. There are very few scientific studies on this topic and thousands of dietary supplements, so we cannot know for sure, but this is unlikely to be true for the vast majority of dietary supplements. 

As discussed previously, bioavailability determines what percentage of a dietary supplement will reach the blood when consumed orally. Unless bioavailability is so poor that receiving an adequate dose orally would be impractical, then there should be no need for intravenous delivery. Yes, IV delivery will increase the amount of supplement that reaches your blood in comparison to taking the same dose orally, but so will taking a higher dose orally. IV delivery will not change the properties of the supplement once it is in your blood, only increase the efficiency with which it gets there.

Case 2: To deliver many supplements all at once over a short period of time

One advantage of an IV drip is that it delivers its entire contents, possibly containing dozens of different supplements, directly into the blood over a much shorter time period compared to oral delivery. There’s a perception that this can offer some kind of ‘quick health fix’ – get all your dietary supplement requirements in one go so you don’t have to worry about what you eat or what supplements you take. 

In reality, getting the entire dose at once is not necessarily a good thing for several reasons. Firstly, high levels of certain micronutrients can be toxic. So, while a given dose of a supplement being slowly absorbed by the gut over the course of hours may be safe, that same dose being delivered directly into the circulation over half an hour may be harmful. 

Secondly, unlike carbohydrates and fats, many dietary supplements cannot be stored by the body when in excess. This means that the body will use what it needs when it needs it, and excrete the rest in the urine. In these cases, it may actually be better if the supplement is absorbed over a longer period of time, because blood levels will remain elevated for longer. Delivering the entire dose to the blood at once could result in most of that dose ending up, quite literally, down the toilet.

At this point, it’s worth remembering that we’re talking about travelling to a private clinic and having a canula inserted into your vein, then waiting 30 minutes to an hour for the treatment to be delivered, usually at considerable expense. You’d want to be fairly certain that this procedure was at least as beneficial than taking a handful of pills. Even if there were some benefit to delivering oral supplements intravenously, there is no telling how frequently someone would need to receive this treatment for it to have a significant health impact.

Case 3: To deliver supplements that don’t survive the gut

There may be some cases in which IV delivery is the only way of reliably getting a supplement into the body. Perhaps it is rapidly degraded and no viable precursors exist, or perhaps it produces harmful byproducts when it is metabolised in the gut. In these cases, there may be a scientific argument to be made for the value of IV delivery. The problem is that if an intravenous drip is the only viable way of getting a supplement into the body, there is unlikely to be much research about whether it works, let alone what the optimal dose is or how often you would need to receive the treatment for it to be of significant benefit.

Safety

Any potential benefits of IV delivery need to be weighed against the inherent risks that come with being hooked up to an IV drip. The most serious of these is the risk of microorganisms being introduced into the bloodstream through improperly sterilised equipment, leading to severe infection (septic shock). The US Food and Drug Administration (FDA) has documented at least one suspected case of this in a woman who received an IV vitamin infusion.

The take home message

IV delivery of dietary supplements does not provide the ‘quick fix’ some may be hoping for, and may actually be worse than taking the same supplements orally. Thus, the potential advantages of delivering a supplement intravenously need to be weighed on a case-by-case basis. IV delivery may be useful for compounds that don’t survive the gut, but until their health benefits are properly established, it’s hard to justify the expense, unpleasantness, and above all the risks associated with these treatments. Ultimately, everyone is free to decide for themselves how far they’re willing to take their quest for longevity, but we also need to make sure we aren’t reducing our longevity by accident.