How soon do you feel less tired after a B12 injection?

Have you been taking your B12?

Many lethargic chronics aren’t aware they’re lacking this valuable vitamin, yet it is crucial for cognitive health and diminishing fatigue.

As a faster and more potent solution, B12 injectables are conquering the market with amazing results for B12 deficiency side effects.

But how soon do you feel less tired after a B12 injection?

Check out this article for more information about B12 injectables, what types are best for boosting energy levels and how to use them properly.

How do vitamin B12 injections work?

B12 injectables are just as the words suggest – a cobalamin vitamin solution that is injected as an intramuscular shot.

B12 is crucial for the creation of red blood cells, thus playing a significant role in proper metabolic function and energy production. What brings us out of bed and keeps us moving on a cellular level is amongst other things attributed to B12.

You may wonder why in the world you should subject yourself to intravenous vitamin boosting, but there are notable advantages of shots to traditional oral supplementation.

Firstly, this mode of administration is more effective as it spreads the solution directly into your bloodstream where it is 100% utilized. On the other hand, oral B12 tablets need time to be digested and absorbed and might lose their full potency in the process.

What’s more, you can take your shots weekly or even monthly and not worry about daily tablet counting.

Types of B12 injections

There are two common forms of B12 injectables:cyanocobalamin and hydroxocobalamin.

Both of these essentially similar B12 coenzymes have been used in clinical studies for treating chronic fatigue syndrome (CFS) and are showing fantastic results.

Apart from dealing with poor B12 absorption, Cyanocobalamin injections showed effectiveness in treating anaemia and preventing nerve damage. Alongside the side effects of low iron levels, anaemic patients can also develop issues with potassium deficiency that can contribute to the feeling of fatigue, anxiety and depression.

However, while it costs less, cyanocobalamin is also less potent than hydroxocobalamin and in that sense may not be such an effective energy booster as its counterpart.

Hydroxocobalamin is a more favourable B12 coenzyme for injectables as it stays longer in the body and is mostly used for treating symptoms of pernicious anaemia. Not only does it work right away but research also showed its direct effect on tiredness, creating an instant sense of an energy rush and better focus.

How quickly do B12 injections work?

Unfortunately, we can’t pinpoint the exact time when a B12 injection will work, since there are various factors that dictate its effect, such as diet, the starting B12 amount (the level of deficiency), other underlying issues such as anaemia, neurological issues, etc. How fast you’ll experience change from the shot also depends on how your body utilizes the vitamin solution.

Generally speaking, B12 injections do work faster than oral supplements as they are directly injected into the bloodstream and are most likely to demonstrate effects on mood and energy levels within the first 24-72 hours.

A study examining injectable B12 supplementation on recovering cancer patients showed that only 30 days of weekly injections managed to alleviate neurological issues related to B12 deficiency.

More research compared oral and injectable B12 supplementation and reached tangible improvements in neurological function 3 months after regular application.

It’s safe to conclude that long term B12 intravenous treatment may not only help with immediate symptoms like tiredness but also lead to more complex neurological improvements.

How soon do you feel less tired after a B12 injection?

The scope of effectiveness will also depend on what you’re looking to solve with the B12 intravenous treatment.

Simply put, it’s not the same if you’re looking to cure deficiency-caused anaemia or just eliminate fatigue and lethargy.

Luckily, when it comes to fatigue and low energy levels, a single shot of B12 may give a subjectively improved feeling of boosted energy, better focus, and help with tiredness within the first 24-72 hours.

Moreover, research indicates that the long-term effects of B12 shots may have a more permanent effect on energy levels. A pilot study examining the effectiveness of B12 for tiredness discovered that only 2 weeks upon 5mg shots of cobalamin actually worked for patients, their subjective response being ‘better appetite, mood, energy, sleep and a general feeling of well-being.

Another study investigating the effect of B12 injections on patients experiencing fatigue due to hemodialysis showed that these shots helped patients profoundly reduce fatigue and tiredness after only a month of use and continued to show results in the next 3 months.

With this it’s clear that as ‘tiredness’ and ‘lethargy’ remain relatively subjective, so do the results of the B12 application.

On the bright side, clinical studies have shown that B12 overdose is highly unlikely and the side effects of too much B12 are unnoticeable compared to immediate the undeniable benefits. So if you’re not getting the results in the first day or two after your B12 shot, consider giving it at least a few weeks in order to get the best out of it.


Why do I feel tired after the B12 injection?

One reason this may happen is if the tiredness you were experiencing isn’t actually related to B12 deficiency and you should start looking for other underlying causes of your symptoms. Are your iron levels also low? This is something you should definitely check.

Another reason may be the already-developed anaemia that requires longer treatment for true results.

Finally, injecting needles may just be too invasive of a procedure and cause stress, dizziness, physical reactions and sensations such as itchiness, swelling of the injected area, redness, and an overall subjective feeling of physical exhaustion.

This may be your sign to maybe try out oral supplementation rather than deal with needles.

How long do vitamin B12 shots last?

General practice is to administer B12 injections once a week or even once a month until the results are visible. This will also depend on the severity of your problem and the desired results. Hydroxocobalamin stays in the system longer, usually creating immediate results, but it may take a few weeks to work if you need to boost B12 levels.

How often should you have B12 injections?

This also depends on the severity of the B12 deficiency you’re dealing with. If there’s an underlying neurological problem, your designated practitioner may turn to monthly injections for a longer period (even permanently). Dietary-caused anaemia and B12 deficiency may take fewer injections to deal with the common fatigue and superficial symptoms.

Overdosing with B12 is not very likely, yet too frequent administration may cause side effects like nausea, skin swelling and redness (on the injected spot), and similar. Consult with your practitioner about the amount and frequency of the injections. Most treatments are distributed either on a weekly or a monthly basis.

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