Vitamin B12 Shots for Weight Loss | The Glenmore Clinic
Weight Loss

Vitamin B12 Shots for Weight Loss

February 9, 2023 9 min read

Key Takeaways

  • Vitamin B12 is an essential nutrient for energy, red blood cell production, DNA synthesis, and nervous system function.
  • Deficiency is common — especially for vegans, vegetarians, and people with absorption issues — and can cause fatigue, brain fog, and mood changes.
  • Injections bypass the digestive system, so they raise B12 levels more reliably than tablets for people who don't absorb it well.
  • B12 shots support energy and metabolism as part of a weight loss plan, but they aren't a stand-alone fat burner — a blood test is the honest first step.
  • The simplest next step is a consultation — call 403.452.5699 or book online.

Vitamin B12 shortage is common, and the reasons for this vary. But it usually has to do with our lifestyle and diet.

Obtaining an adequate supply of vitamin B12 can be challenging, especially for vegans and vegetarians, since the nutrient is only found in animal-based foods.

Signs of a B12 Deficiency

Vitamin B12 is an essential vitamin that our body needs for many key functions. As a water-soluble vitamin, it helps with DNA synthesis — the production of new cells — and helps to produce red blood cells, which carry oxygen throughout the body. It also plays a critical role in producing energy and maintaining proper neurological function, including the functioning of the central nervous system.

When there is a lack of vitamin B12 in the body, it can result in symptoms of deficiency:

  • Fatigue. A common symptom — many people experience feelings of tiredness and low energy levels.
  • Brain fog and memory loss. Also common, as well as neurological problems such as numbness and tingling in the limbs.
  • Heart palpitations. Palpitations and rapid heartbeat can occur, as well as pale skin and complexion.
  • Muscle weakness. People may feel weaker than usual, especially during physical activity.
  • Mood changes. Mood changes and irritability can occur, as well as loss of appetite and weight.
  • Digestive issues. Problems such as constipation can be a symptom, and in severe cases, reproductive problems may occur.

It's important to note that these symptoms can also be caused by other health issues, and it is essential to speak with a doctor for an accurate diagnosis. If you are experiencing any of these symptoms, your doctor may recommend a blood test to check your vitamin B12 levels. Early detection and treatment can help prevent more significant health problems in the future.

The honest first step: a simple blood test tells you whether your B12 is actually low. Shots make a real difference for people who are deficient — and relatively little for people who aren't. Knowing your levels is the best way to spend your time and money wisely.

How Long Does a B12 Shot Last?

The length of time that vitamin B12 stays in your body after an injection can vary greatly, and there are several factors that can influence this.

While it is not possible to determine an exact time frame, the vitamin is rapidly absorbed into the bloodstream. Depending on individual factors such as dietary habits, medication use, age, medical disorders, and lifestyle choices, the length of time that vitamin B12 stays in the body can vary.

For those without a vitamin B12 deficiency, the majority of the vitamin B12 from an injection will be absorbed and quickly eliminated through urine. In contrast, those with a deficiency may store more of the vitamin in the liver, allowing them to feel the effects of the shot for longer.

Lifestyle choices such as alcohol consumption and medication use can also affect the longevity of vitamin B12 in the body. People with liver disorders or gastrointestinal problems may have difficulty storing the vitamin, leading to the need for more frequent injections. Additionally, as we age, our bodies may struggle to store vitamin B12, and additional injections may be necessary to maintain healthy levels.

How Often Can You Get a B12 Shot?

The frequency of B12 injections varies based on several individual factors, such as age, activity level, body-fat ratio, weight loss goals, metabolic rate, energy levels, and the ability to absorb B12.

These factors can influence how much and how often you need B12 treatment to support your metabolism and energy. It is common for patients to receive regular injections to maintain results. If a patient is naturally deficient in B12, monthly injections may be the most effective. On the other hand, some patients may only need injections every three to four months. The ideal frequency will be determined on a case-by-case basis to meet the specific goals of each patient.

B12 Shot Benefits

When people struggle to maintain sufficient vitamin B12 levels due to an absorption problem or a vegan or vegetarian diet, B12 supplements often come to their rescue.

Unlike vitamin B12 tablets that must go through our stomach before reaching the bloodstream, reducing our body's absorption rate, a vitamin B12 injection directly delivers the much-needed nutrient into our blood. With this direct delivery, the following benefits can be seen:

  • Balanced metabolism
  • Increased energy levels
  • Improved cognitive function
  • Better sleep
  • Better mood
  • Support for healthy weight loss

Vitamin B12 injections are considered safe and come with no major side effects for most people. The effects of a vitamin B12 shot usually last between 48 and 72 hours after the injection, but since every body is unique, the duration may vary. Depending on the patient's vitamin B12 deficiency, the doctor may prescribe a short series of injections in the first week of treatment.

Side Effects of a B12 Shot

B12 shots can cause some side effects, which can include:

  • Injection-site reactions. Pain, redness, swelling, and irritation at the injection site may occur shortly after the shot. There is also a small risk of infection, so be sure to follow your provider's orders for wound care.
  • Gastrointestinal effects. Nausea, upset stomach, vomiting, mild diarrhea, and indigestion. These typically pass within a week, but contact your doctor if you experience them severely.
  • Skin reactions. A rash may develop around the injection site. In the case of difficulty breathing, seek emergency care immediately, as this could be a sign of an allergic reaction. Itching of the skin near the injection is another possible side effect.
  • Internal effects. Headaches, dizziness, weakness, numbness and tingling, joint pain, and a low-grade fever. If a fever persists, contact your doctor.
  • More serious effects. Rarely, B12 shots may contribute to low potassium levels, which can cause muscle cramping, extreme fatigue, and an irregular heartbeat. If you experience any of these, contact your doctor immediately.

How Quickly Does a B12 Shot Work?

The onset of action and the effectiveness of B12 shots can vary from person to person. In general, B12 shots start to work within a few hours of being administered.

However, the time it takes for the body to absorb the vitamin B12 and for its effects to become noticeable can range from a few days to several weeks, depending on factors such as the individual's nutritional status, the dose received, and the underlying cause of the deficiency.

It's also important to note that the full effects of a B12 shot may not be seen for several weeks, as the body slowly builds up its stores of this important nutrient. The frequency and number of shots needed will be determined by your physician based on your specific needs and health status.

Where Can I Get a B12 Shot?

B12 shots can be obtained from various sources, including a weight loss clinic. The Glenmore Clinic offers B12 injections as part of our weight loss programs, often alongside our Vitamin B Complex and lipotropic injections. Be sure to discuss your medical history and any current medications with the clinic before getting a B12 shot, as some health conditions may contraindicate its use. For a deeper look at the science, our honest guide to B12 shots in Calgary covers who genuinely benefits.

The Bottom Line

Vitamin B12 is an essential nutrient for the proper functioning of our body. A deficiency can result in a wide range of symptoms, including fatigue, brain fog, memory loss, heart palpitations, pale skin, muscle weakness, mood changes, appetite loss, and constipation. If you are experiencing any of these symptoms, it is important to talk to a doctor for an accurate diagnosis and treatment plan — and to remember that B12 shots support a weight loss plan rather than replacing diet and exercise.

The Glenmore Clinic is located at 1600 90 Ave SW, Suite A305, in Calgary. You can reach us at 403.452.5699 or book a consultation online.

Wondering If B12 Shots Are Right for You?

A short, physician-led consultation — and a simple blood test — is the honest way to find out. We'll look at your levels and goals and recommend only what genuinely helps. No pressure.

Call 403.452.5699 Book a Consultation

You deserve to look and feel amazing.

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