What are the Side Effects of B12 Shots?

B12 shots are a popular way of supplementation for people who have deficiencies in this vitamin. Although B12 shots have a number of potential health benefits, they may also lead to some adverse side effects. Before you choose to get b12 shots, it’s important to understand the potential side effects and where to get them.

Mild Side Effects of B12 Shots

Taking B12 shots can boost energy levels and improve overall health, but it can also have mild side effects that should not be ignored.

Here are some common but mild side effects of B12 shots:

Side EffectDescription
PainB12 shots can sometimes cause pain at the injection site.
SwellingIn some cases, the injection site may swell or become red and itchy.
DizzinessB12 shots can cause dizziness and lightheadedness in some individuals.
NauseaSome people may experience mild nausea after taking B12 shots.

While these side effects are typically mild and go away on their own, it’s important to consult with your doctor if you experience any discomfort or have concerns about B12 shots. Pro tip: While B12 shots are generally safe, it’s best to get them administered by a medical professional to reduce the risk of complications.

Injection Site Reaction

One of the common side effects of B12 shots is an injection site reaction, which happens when the body reacts to the needle or the solution being injected, causing pain, swelling or redness at the site of injection. However, this side effect is usually mild and goes away on its own after a few days.

Here are some tips that can help minimize the injection site reaction:

Apply a warm compress to the injection site to reduce pain and swelling.
Avoid touching or scratching the injection site to prevent infection.
Rotate the injection site with each shot to allow the skin time to heal.
If the injection site reaction persists for more than a week or gets worse, seek medical attention.

Nausea and Vomiting

Nausea and vomiting are among the possible side effects of B12 shots, although they are not very common. Other potential side effects of B12 injections include headache, dizziness, swelling, and redness at the injection site.

To reduce the risk of nausea and vomiting after a B12 shot, try the following tips:

Hydrate yourself well both before and after your injection.
Eat a light, low-fat meal before your injection.
Sit down and relax for a few minutes after your injection.

If your nausea and vomiting persist or worsen, contact your healthcare provider immediately. Keep in mind that any unusual or persistent symptoms following a B12 shot should be reported to your doctor promptly.

Pro Tip: It is always recommended to consult with a healthcare provider before starting any supplementation regimen.


Diarrhea is one of the most common side effects of B12 shots, which is a medical treatment for patients with Vitamin B12 deficiency. Although B12 injections have several potential benefits, such as aiding in the formation of new red blood cells and improving nerve function, experiencing loose stools and diarrhea can be a downside.

The reason behind diarrhea after receiving Vitamin B12 shots can be explained by the body’s reaction to increasing the amount of Vitamin B12 in the system, which can cause an altered digestive process. This can cause stomach cramps, bloating, constipation, or diarrhea.

Anyone experiencing diarrhea or any other side effects after B12 injections should consult their doctor for proper care and treatment advice. Even though B12 shots can relieve various health issues, proper care and management is necessary to avoid side effects like diarrhea.

Serious Side Effects of B12 Shots

B12 shots are commonly used to treat vitamin B12 deficiencies and provide an energy boost. However, there are some serious side effects associated with this treatment that should not be ignored.

Some of the common side effects of B12 shots include irritation or pain at the injection site, redness or itchiness, headache, and nausea. However, serious side effects are rare but may include shortness of breath, rapid or irregular heartbeat, muscle weakness, and vision problems.

If you notice any of these symptoms after receiving a B12 shot, seek immediate medical attention. Additionally, if you have a history of blood clots, allergies, or certain medical conditions, consult with your doctor before receiving B12 shots to avoid any potential complications.

Pro Tip: Be sure to discuss any potential risks or side effects with your doctor before beginning B12 shot treatment.


Anaphylaxis is a serious potential side effect of B12 shots, and those who experience it require immediate medical attention.

Anaphylaxis is a severe allergic reaction that occurs when the body’s immune system overreacts to an allergen, in this case, the B12 shot. Symptoms of anaphylaxis can include difficulty breathing, swelling of the face or throat, rapid pulse, hives, and a drop in blood pressure.

While anaphylaxis is a rare side effect, those who have a history of severe allergic reactions or those who have experienced a reaction to a B12 shot in the past are more likely to experience it again. It is crucial to seek immediate medical attention if you experience any anaphylaxis symptoms after receiving a B12 shot. Pro tip: Be sure to inform your healthcare provider if you have a history of allergic reactions before getting B12 shots.

Chest Pain and Shortness of Breath

B12 shots are often used to treat vitamin B12 deficiency, but they can cause certain side effects in some people. Chest pain and shortness of breath are among the rare but serious side effects associated with B12 shots.

Here’s what you need to know:

Side EffectWhat to Do
Chest painIf you experience chest pain after getting a B12 shot, seek medical attention immediately. This could be a sign of a serious allergic reaction or other side effect that requires immediate treatment.
Shortness of breathThis is another symptom that could indicate a serious reaction to B12 shots. If you have difficulty breathing or feel like you’re not getting enough air, seek medical help right away.

While these side effects are rare, it’s important to be aware of them and seek prompt medical attention if you experience any concerning symptoms after getting a B12 shot. Pro tip- Always consult your healthcare provider before starting any new medication or supplement regimen.

Vision Problems

Some individuals who receive B12 shots may experience vision problems as a side effect. These vision problems are often temporary and resolve on their own, but individuals should seek medical attention if they persist.

Common vision problems that individuals may experience after receiving B12 shots include blurry vision, sensitivity to light, and double vision. In rare cases, individuals may experience optic neuropathy, a condition in which there is damage to the optic nerve, resulting in vision loss.

It is important to note that these side effects are not common, and most individuals who receive B12 shots do not experience any problems with their vision.

If you experience any vision problems after receiving a B12 shot, it is important to speak with your healthcare provider immediately to determine the underlying cause and appropriate treatment. Pro Tip: Before getting the B12 shot, speak with your healthcare provider about the potential side effects and ask if any precautions should be taken.

Where to Get B12 Shots

B12 shots are a great way to ensure that you have the proper amount of Vitamin B12 in your body. Receiving regular B12 injections can help to boost your energy levels, improve your mood, and help to support a healthy metabolism. But before getting B12 shots, it is important to know where to get them, as well as the potential side effects of B12 shots.

Let’s explore both of these topics in more detail.

Doctor’s Office and Clinics

Vitamin B12 shots are usually available at doctor’s offices and clinics, making them easily accessible to anyone who needs them. These shots are typically administered in the arm, thigh or buttocks, and the process is quick and relatively painless.

So, what are the side effects of B12 shots? Some people may experience mild side effects such as pain or redness at the injection site, nausea, or diarrhea. However, these side effects are usually temporary and go away on their own.

In rare cases, some people may experience more severe side effects like an allergic reaction, shortness of breath or chest pain. If you experience any of these symptoms after receiving a B12 shot, seek medical attention immediately.

Pro tip: If you have never had a B12 shot before, it is recommended to speak with your healthcare provider about the appropriate dose and any potential risks, especially if you have a history of allergies or chronic medical conditions.

Pharmacies and Drug Stores

Pharmacies and drug stores are some of the best places to get B12 shots conveniently and safely. These stores have licensed pharmacists and trained staff who can administer the shots and offer guidance on the proper usage, dosage, and side effects of the supplement.

Vitamin B12 is used to boost energy levels, improve cognitive health, and treat various conditions such as anemia and nerve damage. However, like any medication, it has possible side effects that range from mild to severe allergic reactions or interactions with other drugs. These effects include headache, skin rash, upset stomach, diarrhea, and difficulty breathing, among others.

It is important to inform your pharmacist or doctor about any existing medical conditions or medications you are taking before getting the shots. Also, make sure to follow the dosage instructions to avoid overdosing or misusing the supplement.

Online Retailers and Services

B12 shots can be obtained from various online retailers and services, making it a convenient option for those seeking the benefits of this vitamin.

Here are some online options:

The Vitamin ShoppeA well-known retailer of health supplements and vitamins, offers B12 shots both in-store and online.
AmazonA popular online retailer with a broad selection of B12 shots from various brands.
B12Shot.comA website dedicated to providing information about B12 shots and offers the service of purchasing shots online.

While B12 shots are generally safe, some side effects may occur depending on the individual’s health and dosage. These side effects include headache, dizziness, nausea, and low blood pressure. It is always best to consult with a healthcare professional before starting any new vitamin regimen, including B12 shots.