Average Weight Loss On Phentermine And B12 Shots

You are here:
Average Weight Loss On Phentermine And B12 Shots - My Concierge MD

Are you on a weight loss journey with phentermine and B12 shots and wondering how much you should expect to lose?

As a weight loss medication doctor, I understand your desire for results and eagerness to see those numbers on the scale decrease. It’s a common question, and the answer can sometimes be complicated.

While there are averages based on clinical studies, weight loss is a highly individualized process. Numerous factors can influence your results, from your starting weight and body composition to your dietary choices and activity level.

So, let’s examine the research more closely, consider the variables that impact weight loss, and, most importantly, learn how to set realistic expectations and optimize your journey with phentermine and B12 shots.

Average Weight Loss On Phentermine and B12 Shots

Studies show an average weight loss of 3-6 lbs/month for women and 5-8 lbs/month for men when Phentermine is combined with a low-calorie diet and exercise. While B12 is essential for energy metabolism, there is no conclusive evidence that B12 shots solely aid in weight loss.

Phentermine: Cutting Down the Cravings

Phentermine is a prescription drug that helps curb your appetite. It’s often prescribed to those who are significantly overweight and need a bit of extra help to get started. By reducing hunger, Phentermine makes it easier to stick to a low-calorie diet without feeling deprived.

B12 Shots: Boosting Your Energy

Vitamin B12 is essential for your body, playing a pivotal role in keeping your nerves and blood cells healthy.

When taken as shots, B12 can significantly boost energy when cutting calories and might otherwise feel sluggish. Some people also believe that B12 can help speed up metabolism, aiding in weight loss.

Real-World Results: What People Are Seeing

So, what kind of weight loss are we talking about here? Results can vary quite a bit from person to person, but here’s a general idea of what to expect:

Initial Phase (First Month)

Most people see the most dramatic results in the first month. It’s common to lose between 5 and 10 pounds during this time. This rapid weight loss is mainly due to significantly reduced calorie intake and water weight loss.

Steady Progress (Following Months)

After the initial phase, the rate of weight loss typically slows down but remains steady. People tend to lose about 1 to 2 pounds per week, which can add up to a total loss of 15 to 30 pounds over three to six months.

Phentermine for Weight Loss: How it Works

The Science Behind It: Appetite Suppression

Phentermine works primarily by suppressing your appetite. It belongs to a class of drugs called sympathomimetic amines, which are similar to amphetamines. Here’s how it works:

Central Nervous System Stimulation:

Phentermine stimulates the central nervous system, much like a stimulant. This leads to the release of certain chemicals in your brain that control appetite.

Increased Levels of Neurotransmitters:

The medication increases neurotransmitters such as norepinephrine, serotonin, and dopamine. These chemicals signal the brain that you’re full and reduce the feeling of hunger.

Energy Boost:

Phentermine stimulates the central nervous system, giving you more energy. This can help you feel more motivated to exercise, which is crucial to losing weight.

How Do B Vitamins Maximize Phentermine Weight Loss?

B vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin), are essential nutrients that play a critical role in energy production and metabolism. Here’s how they contribute to weight loss:

Energy Production

B vitamins are critical players in converting the food you eat into energy. They help break down carbohydrates, fats, and proteins, ensuring your body has the energy to function correctly. This is especially important when you’re on a calorie-restricted diet and need to make the most of the nutrients you consume.

Metabolism Boost

Specific B vitamins, particularly B6 and B12, are involved in metabolic processes that help your body burn calories more efficiently. A faster metabolism means you’ll burn more calories even at rest, aiding in weight loss.

Reducing Fatigue

Dieting can often lead to fatigue, making it difficult to maintain an active lifestyle. B vitamins, especially B12, are known for their energy-boosting properties. They can help combat the tiredness of calorie restriction, allowing you to stay active and burn more calories.

Phentermine and B12 Shots’ Side Effects

While these treatments can be effective, understanding the risks can help you make an informed decision and manage any adverse effects if they arise. Here’s a closer look at the side effects of Phentermine and B12 shots.

Phentermine Side Effects

Dry Mouth: Phentermine users frequently complain of persistent dry mouth. Drinking plenty of water can help alleviate this symptom.

Insomnia: Since Phentermine stimulates the central nervous system, it can make falling or staying asleep difficult. Taking the medication earlier in the day might mitigate this.

Increased Heart Rate: You might notice your heart beating faster than usual. This is a common reaction to the medication’s stimulant effects.

Nervousness or Anxiety: Some users report feelings of restlessness, anxiety, or jitteriness.

Less Common but Serious Side Effects:

Elevated Blood Pressure: Phentermine can significantly increase blood pressure. Regular monitoring by a healthcare provider is crucial.

Heart Palpitations: Irregular or rapid heartbeats can occur, which can be concerning and require medical attention.

Chest Pain: Any chest pain should be taken seriously and reported to a doctor immediately.

Shortness of Breath: Difficulty breathing can be a severe side effect that warrants immediate medical attention.

Mood Changes: Some individuals may experience mood swings, irritability, or depression. These symptoms should be discussed with a healthcare provider.

B12 Shots Side Effects

Pain at Injection Site: It’s normal to experience some pain, redness, or swelling where the injection was given. This usually resolves on its own within a few days.

Mild Diarrhea: Some people might experience gastrointestinal discomfort, including diarrhea, after receiving B12 shots.

Itching or Rash: Allergic reactions to B12 injections are rare but possible. Symptoms might include itching, rash, or hives.

Dizziness or Headache: Some individuals report feeling dizzy or experiencing headaches after the injection.

Severe Allergic Reaction (Anaphylaxis): Although extremely rare, a severe allergic reaction can occur. Symptoms include difficulty breathing, swelling of the face or throat, and a rapid heartbeat. This is a medical emergency and requires immediate attention.

Who Shouldn’t take Phentermine?

Phentermine can be a game-changer for many struggling with weight loss, but it’s not suitable for everyone. Certain health conditions, medications, and personal circumstances make it risky for some people. Here’s a closer look at who should avoid Phentermine and why.

Heart Conditions

Phentermine acts as a stimulant, elevating heart rate and blood pressure. This makes it particularly dangerous for individuals with pre-existing heart conditions. If you have:

  • Coronary Artery Disease: The added strain from Phentermine could increase the risk of a heart attack.
  • Congestive Heart Failure: Phentermine can exacerbate symptoms by putting additional pressure on an already struggling heart.
  • Severe Hypertension: High blood pressure is a serious risk factor, and Phentermine can worsen it, leading to potentially life-threatening complications.


People with hyperthyroidism already have an overactive thyroid gland, which accelerates metabolism and increases heart rate. Adding Phentermine to the mix can further overstimulate the system, leading to increased heart rate, anxiety, and other severe symptoms.


Glaucoma is characterized by increased pressure in the eyes, which can damage the optic nerve. Since Phentermine can raise blood pressure, it may also increase intraocular pressure, worsening the condition and potentially leading to vision loss.

History of Drug Abuse

Phentermine has the potential for abuse and dependency. If you have a history of substance abuse, using Phentermine can lead to addiction. It’s crucial to explore other weight loss methods that do not carry this risk.

Pregnancy and Breastfeeding

Pregnancy and Breastfeeding - Weight Loss On Phentermine And B12 Shots - My Concierge MDPhentermine is not safe for use during pregnancy or while breastfeeding. It can harm the developing fetus or the nursing infant. If you are pregnant, planning to become pregnant, or breastfeeding, you should avoid Phentermine.

Certain Medications

Phentermine can interact dangerously with some medications. You should avoid Phentermine if you are taking:

  • MAO Inhibitors: These antidepressants can cause severe, potentially life-threatening interactions with Phentermine.
  • Other Stimulants: Combining Phentermine with other stimulant medications can significantly increase the risk of cardiovascular side effects.
  • Certain Antidepressants: Especially those affecting serotonin levels, can lead to a serious condition known as serotonin syndrome.
  • Severe Anxiety or Agitation: Phentermine stimulates the central nervous system, which can exacerbate symptoms of anxiety and restlessness. If you suffer from severe anxiety or agitation, Phentermine might worsen your condition, making it unsuitable for you.

Uncontrolled High Blood Pressure

Even if you don’t have other heart conditions, uncontrolled high blood pressure is a significant risk factor. Phentermine can further elevate blood pressure, leading to dangerous complications.

Semaglutide vs Phentermine


Both medications are effective, but studies suggest that Semaglutide may lead to more substantial weight loss compared to Phentermine. Clinical trials have shown that patients on Semaglutide can lose up to 15% of their body weight over 68 weeks, whereas Phentermine users typically see an average loss of 5-10% of body weight over a shorter period.

Duration of Use

Phentermine is generally prescribed for short-term use, usually up to 12 weeks, due to its potential for dependence and side effects. Long-term use is not recommended because of the risks associated with prolonged exposure to stimulant medications.

Semaglutide, however, can be used long-term. It is typically administered once a week via injection and is considered safe for extended use, especially in the context of chronic conditions like obesity and diabetes.

Can I take Semaglutide and Phentermine Together?

Both semaglutide and phentermine can be used for weight loss, but their simultaneous use should be under a healthcare provider’s guidance due to potential interactions and side effects. 

The potential for increased side effects, cardiovascular risks, and the lack of comprehensive research make it crucial to consult a healthcare provider before considering this approach. 

Your doctor can help you navigate the best and safest weight loss strategy tailored to your health needs. Always prioritize safety and professional medical advice over experimentation with powerful medications.

Final Thoughts

Phentermine and B12 shots offer a dynamic duo to achieve weight loss goals. With appetite suppression from Phentermine and energy boosts from B12 shots, you have the tools to kickstart your journey to a healthier you.

At My Concierge MD clinic, we provide personalized support tailored to your needs. Whether you’re aiming to shed a few pounds or make a significant transformation, our team of experts is dedicated to helping you reach your goals safely and effectively.Click here to visit our website and learn more about our services. Your best self is waiting – let’s make it happen together!

Share this post

Book Appointment