B12 Injections: The Energy Boost That Actually Lasts

The “3 p.m. slump” may be a familiar, overused trope in advertising, but if we’re being honest, it’s grounded in reality: many of us are definitely hitting a wall by mid-afternoon most days.

Trouble is, that daily 3 p.m. coffee isn’t helping relieve our overall fatigue. If anything, all it does is contribute to our growing anxiety that there’s something seriously wrong. Why else would we be craving a nap in the middle of the workday, right?

And when we need an energy boost alternative, where do we first look? You guessed it, the internet. One quick search on social media, and suddenly it seems like everyone, from doctors to wellness influencers, is buzzing about B12 injections to combat fatigue and exhaustion.

So do B12 injections actually live up to their online hype? Well, that’s what we plan to find out in this article. We’re going to explore what B12 shots do, how they can help, if they’re right for you, and, most importantly, how you can set your expectations. Because while there are benefits to B12 injections, they’re not a miracle cure.

What are B12 injections for?

Vitamin B12 is integral to the production and support of healthy nerve cells in the body. In addition, it’s used to make healthy red blood cells that are responsible for delivering oxygen to organs throughout the body. A lack of vitamin B12 can result in fatigue, muscle weakness, and overall low energy.

Many people don’t necessarily need vitamin B12 supplementation, especially if they already get enough from a balanced diet. However, supplements (either injection or pill form) are sometimes medically recommended for people with a B12 deficiency: Primarily older adults, people who follow vegetarian or vegan diets, and those who have trouble absorbing nutrients from conditions such as celiac disease, Crohn’s disease, or pernicious anemia.

People who have low B12 may initially be prescribed a pill supplement, but if the oral option doesn’t help to raise their B12 levels, your healthcare provider may recommend B12 injections instead. One thing to remember is that injections are more quickly absorbed into the body than oral supplements, as they bypass the digestive system and go directly into the bloodstream.

It’s also worth noting that the “normal” or “healthy” B12 range was originally defined to prevent clear deficiency symptoms, not necessarily to optimize long-term brain health or healthy aging. Emerging research suggests that people on the lower end of that range may still experience faster cognitive decline compared to those with more robust, optimized B12 levels.

From a wellness perspective, some people opt for vitamin B12 injections not just to correct a deficiency, but to support energy, focus, and overall vitality, especially when their levels are technically “normal,” but not ideal for how they want to feel.

B12 injection benefits (the real talk)

If you have a vitamin B12 deficiency, symptoms can present in physical, neurological, and psychological forms, ranging from extreme exhaustion to loss of appetite to brain fog to depression.

Getting a B12 injection, and thus raising your B12 levels to normal, has the potential to improve not only your energy, but it can also regulate your mood, as well as help with your nervous system health. Plus, untreated vitamin B12 deficiency can lead to irreversible neurological damage.

What’s important to remember about vitamin B12 injections is that while they can improve symptoms linked to B12 deficiency (including fatigue), they’re most helpful for people whose B12 levels are low to begin with — even if those levels don’t meet the clinical threshold for a diagnosed deficiency. In other words, you don’t have to be technically “deficient” to notice improvements in energy, focus, or overall well-being.

Depending on how low your levels are, you may start to feel the effects of a B12 injection relatively quickly, with some people noticing changes within days, and others experiencing more gradual, longer-term benefits over the following weeks.

B12 injections and weight loss (unpacking the claims)

Since B12 injections are linked with overall increased energy, some may take that to mean that a B12 injection equals instant weight loss. Not exactly.

There is no direct link between B12 injections and weight loss. But let’s say you had a vitamin B12 deficiency. Then you took B12 injections to get your levels back to normal: Not only have your symptoms improved, but now you have a new, energetic lease on life that has you eating healthy, exercising more, and ultimately losing weight.

So, yes, it is possible that a B12 injection can play a role in helping you to drop some pounds. But in this scenario, there are a few key factors: Namely, that the B12 injection is a tool in correcting a deficiency, not a magic bullet. Once your B12 levels are normalized, you have a better chance of adopting a healthier lifestyle, which can lead to weight loss.

Who actually needs vitamin B12 injections?

The people who actually need vitamin B12 injections are those with a confirmed B12 deficiency. Certain medical conditions can affect the body’s ability to absorb B12, which leads to deficiency. They include pernicious anemia, gastrointestinal issues (including Crohn’s disease and celiac disease), or even certain gastrointestinal surgeries like gastric bypass.

Other reasons for B12 deficiency include certain dietary factors, such as a vegan/vegetarian diet, aging, and specific medications that interfere with B12 absorption.

If you suspect a B12 deficiency, you’ll want your healthcare provider to confirm a diagnosis through bloodwork – especially before you consider B12 injections. This is because, unless you have a B12 deficiency, a B12 injection likely won’t affect your symptoms.

How to give a B12 injection

Vitamin B12 injections can be administered either intramuscularly (into the muscle) or subcutaneously (under the skin). While B12 injections are usually given in a healthcare provider’s office, your provider may teach you how to administer the doses yourself. There are at-home options available as well.

If you opt to administer your B12 injections at home, it is imperative that you follow all of your provider’s instructions regarding how to draw up B12 medication into the syringe from the vial and how to administer an injection. You’ll specifically want to pay attention to the following steps:

• Sanitizing the injection site and medication vials
• Drawing the medication into the syringe
• Injecting the medication into the body
• Safely disposing of the syringe and needles

You may wish to consider having your provider administer your first few injections until you’re comfortable – and so they can monitor you for any potential allergic reactions. Once you’re used to the routine, however, at-home injections are an option.

B12 injection sites

Common B12 injection sites include the middle of your thigh, the upper arm area (deltoid muscle), the buttocks, the fleshy part of your abdomen, or the fleshy area of your hip. Ultimately, your injection site is up to you, but you will want to change up the location with every injection to minimize inflammation and the risk of tissue damage.

At-home B12 injections

At-home B12 injections are increasingly becoming a feasible option for patients thanks to their growing accessibility and convenience.

Since patients usually start with a schedule of once-a-week B12 injections, it’s understandable that not everyone can get over to their doctor’s office or a clinic that often. That’s where companies like AgelessRx come in: Through expert, medically supervised guidance and a 100% online platform, AgelessRx provides patients with a personalized B12 injection prescription delivered right to their door, as well as step-by-step instructions and ongoing support.

Keep in mind that if you decide to go the at-home route, there are several supplies you’ll need, in addition to a B12 prescription:

• Syringes
• Injecting needles
• Cleaning wipes (containing alcohol)
• Clean gauze/Band-Aids
• Sharps container for disposing of syringes/needles

(If you opt for a vitamin B12 prescription from AgelessRx, your order will include syringes, injecting needles, and alcohol cleaning wipes.)

Make sure you store your B12 medication at room temperature (between 59 and 85 degrees Fahrenheit), away from light and out of children’s reach. Do not use after the expiration date.

Vitamin B12 injections dosage and frequency

The standard dosing protocol for vitamin B12 injections is 1ml/cc per injection once per week. However, dosing protocols will vary by individual and ultimately be determined by your healthcare provider.

The frequency of injections also depends on the individual. But generally speaking, those with significant deficiencies or pernicious anemia may be prescribed either daily or weekly shots before being tapered to monthly maintenance doses.

While it’s common to notice an improvement in B12 deficiency symptoms within the first week, you may need anywhere from three to six months for a full recovery. This is why it’s vital to work closely with your provider to tailor a treatment dosage and schedule that works for you and your body.

How long does a B12 injection last?

A typical B12 injection lasts about one to two weeks, but this entirely depends on what is causing an individual’s B12 deficiency.

Some may need B12 injections daily for around two weeks or until symptoms improve. If diet is the source of B12 deficiency, individuals may not need additional shots (or just once or twice a year). If a chronic condition is the cause of B12 deficiency, people may need B12 maintenance shots approximately every two months.

Should your symptoms return (fatigue, brain fog, irritability) before your next dose, that may be a sign you need to revamp your B12 injection frequency. Speak to your healthcare provider about a schedule that works best for your condition.

How long do vitamin B12 injections take to work?

One of the reasons why patients notice symptom improvement almost immediately after a B12 injection is that the nutrient is delivered directly into the bloodstream instead of going through the digestive system.

Therefore, it’s common to notice effects within 24 to 72 hours, though that depends on your symptoms and your level of B12 deficiency. Some people may not feel better for a few days or weeks.

B12 injection side effects (the good, bad, and temporary)

As with most treatments, there is a risk of side effects with B12 injections, but most of them are manageable.

The most common side effect of B12 injections is irritation and/or soreness at the injection site. To avoid recurrent inflammation, it’s recommended that you switch injection sites with each dose.

Diarrhea is also a potential side effect, but unless it’s recurring or severe, you probably don’t need to report it to your doctor.

However, contact your healthcare provider immediately if you experience any of the following after a B12 injection:

• Allergic reaction (skin rash, itching, hives, swelling of the face, lips, tongue, or throat)
• Swelling of the ankles, hands, or feet
• Trouble breathing

Why do I feel worse after my B12 injection?

About one in 10 patients experiences a temporary worsening of symptoms after their B12 injection. This is due to a handful of reasons:

• The body is adjusting to normalized B12 levels after operating at a deficiency (this can include temporary low potassium levels and high platelet counts as the body resumes a normal production of red blood cells)
• Allergic reactions (see your doctor immediately)

If your symptoms do not resolve quickly (within a few days), contact your healthcare provider for guidance.

What not to do after a B12 injection

The good news is that there aren’t too many restrictions on your routine after getting a B12 injection. At the same time, there are a few guidelines to keep in mind.

First of all, even if you’re experiencing mild irritation, do not rub the injection site. Rubbing can increase your risk of infection, as well as cause further inflammation.

Second, avoid a hot bath for 24 hours after your B12 injection (a warm shower is fine!), as the heat can irritate the injection site.

Third, don’t jump back into your regular exercise routine until about 24 hours after your B12 injection. Your body is still adjusting to its new nutrient levels, and it needs a little time before resuming strenuous workouts.

Finally, hold off on that glass of wine or cocktail for about 48 hours after your B12 injection. Alcohol interferes with your body’s ability to absorb B12, thus negating the injection’s entire purpose.

Are B12 injections safe?

B12 injections are safe for most individuals as a treatment for B12 deficiency, as well as overall wellness. Though, as with any treatment, you will want to ensure the quality and sourcing of your B12 prescription.

AgelessRx, for example, partners with certified 503A compounding pharmacies, which require strict FDA compliance requirements, including regular inspections of their facilities and products, while rigorously following state and federal regulations. All medications are dispensed and shipped from a certified US-based pharmacy, subject to strict manufacturing and approval processes. All medication is purchased from a facility that is registered and inspected by the FDA.

If you are considering B12 injections, you will need to disclose the following conditions to your healthcare provider, as they may affect your treatment:

• Kidney disease
• Leber's disease
• Megaloblastic anemia
• An unusual or allergic reaction to cyanocobalamin (aka the synthetic form of B12), cobalt, other medications, foods, dyes, or preservatives
• Pregnancy, or if you’re trying to get pregnant
• If you are breastfeeding

Although B12 injections are generally safe, medical oversight is imperative, especially if you have a B12 deficiency. The details of your diagnosis will determine your B12 dosage, frequency, and treatment timeline.

How much are B12 injections?

The cost of B12 injections varies by location, provider type, and insurance coverage, with prices ranging from $15 to $100 per shot. Insurance coverage is usually only an option if you have a medically diagnosed B12 deficiency; carriers won’t cover you if you’re getting B12 shots for wellness purposes.

AgelessRx offers accessible, at-home B12 injections through its online subscription services, with a starting price of $75 per month.

Getting started with B12 injections

The first step toward getting started with B12 injections is to undergo bloodwork and confirm whether or not you have a vitamin B12 deficiency.

Next, you’ll want to find a healthcare provider who will listen to your concerns and who will formulate a treatment plan tailored to your needs.

Here are some questions you’ll want to ask any potential provider:

• What is the underlying cause of my B12 deficiency?
• Do I need further testing?
• Do you recommend I receive B12 injections?
• If so, how frequently will I receive the shots, and for how long?
• When can I expect my symptoms to improve?
• What should I do if my symptoms don’t improve?

As for whether you want to administer your B12 injections at home or receive them in the doctor’s office, that’s entirely a personal decision. Does your schedule allow for weekly doctor’s office visits? What is your budget for B12 injections/does your insurance cover them? Will at-home injections make your life easier?

While B12 injections can improve your quality of life, remember that they’re not an instant miracle cure: There will likely be a period of adjustment. But if you establish realistic goals and expectations at the outset, you’ll reap the benefits sooner rather than later.

B12 injections: Our sum-up

If you’re suffering from a vitamin B12 deficiency, injections can be a game-changer.

However, it’s important to remember that B12 injections are not a one-size-fits-all solution, especially if you’re looking for a quick energy boost. Unless you have an actual deficiency, B12 injections are likely not going to make a difference when dealing with fatigue in the long-term.

Still, your energy journey is yours to navigate, whether you have a confirmed B12 deficiency or are just suffering from that daily 3 p.m. slump. The way you take control of your health is by empowering yourself through informed choices.

To learn more about vitamin B12 injection options, consult your healthcare provider or head over to agelessrx.com.