Healthy Hormones

Prescription Medications for Weight Loss

People are always looking for new and effective ways to lose weight.

Weight loss has become a multi-billion dollar industry.  This includes diets, exercise equipment, supplements, and even prescription medications.

How do you know which medications work and which don't?  Which are safe for you and which should you avoid?

In this article, I will discuss the most commonly prescribed medications available for weight loss.  I will discuss how they work, any potential side effects, and how effective they can be.

Here we go...


Always Identify the Root Issues First

It is important to take a moment here and discuss something before going any further.

Weight gain and obesity are complicated issues. 

There are usually several things going on that have caused you to gain weight.  These include poor diet, lack of physical activity, emotional stress, hormone imbalances, lack of sleep, and others.  Click here to read more.

If you are looking for a pill or shot to solve all of these issues, you are going to be severely disappointed.  

A medication by itself will fail 100% of the time if the root issues of the weight gain have not been identified and addressed.

That would be like putting a band-aid over a bullet wound.

There is a ton of bad information on the internet about any topic, including medical topics.  You must be smart and have your antenna up to make sure you are getting correct information.

For example, this paragraph is from, a respected government resource for medications. In this case, it is discussing Belviq, a commonly prescribed weight loss medication that we will be talking about later in this article:

I guess they think you can continue to eat how you have been eating and just depend on the medication to do all of the work.

Do you see my point?

If you want to lose weight and keep it off, you are going to need an extensive evaluation from a medical provider who is willing to sit down, listen to you, and work with you.  They will need to take a thorough medical history and order specific lab tests to identify any hormonal and other imbalances in your body.

You would also likely benefit from intensive nutritional instruction from a certified nutritionist with experience and training in helping people lose weight.  You will need a dietary plan that is custom made specifically for you, your food preferences, and your health situation.

Once you have completed all of the above, then (and only then) it may be appropriate for you to consider a weight loss medication for at least a short period of time.

Now let's discuss the most commonly prescribed medication for weight loss:

Prescription Weight Loss Medications

I am going to discuss several medications that are used for weight loss in this article.  

Keep in mind that I do not normally prescribe the majority of these.  However, you may have heard about many of them, so I want to give you some basic knowledge of how they work as well as their effectiveness and potential side effects.

I list them in decreasing order of effectiveness based on my experience and research.

1.  GLP-1 Agonists

Liraglutide (Victoza) was first FDA approved for treatment of Type 2 diabetes in 2010.  It was approved for weight loss and repackaged as Saxenda in 2014.

- How does it work? - GLP-1 agonists are one of the most potent appetite suppressants.  They act on the glucagon receptors which slows down gastric emptying.  The reduction in gastric emptying sends a signal to your brain that you are full.  It also directly reduces insulin and leptin levels which reduces inflammation and helps maintain weight loss even after stopping the medication.

- Effectiveness - 45-60% of patients lose at least 5% of their body weight, while about 18% lose at least 10% of their body weight.

- How do you take it? - an injection at bedtime.  Start with 0.6mg then increase the dose by 0.6mg each week until you reach the target dose of 3mg daily.

- Side Effects - nausea/vomiting, diarrhea, constipation, hypoglycemia, headache, loss of appetite. Potential increased risk for medullary thyroid tumors and pancreatitis.

- Contraindications - Family history of medullary thyroid tumors, pregnancy, and history of reaction to this class of medication.

- Who should consider taking it? - Excellent choice if you also have insulin and leptin resistance, including type 2 diabetes.

- Score - 10/10 in my experience.  Expensive and may not be covered by insurance.

2.  phentermine-topirimate (Qsymia)

The FDA approved Qsymia for weight loss in 2012.

- How does it work? - Qsymia contains 2 different generic medications, phentermine and topirimate. Phentermine is an appetite suppressant that directly reduces your appetite while simultaneously increasing your basal metabolic rate.  Topirimate is an anti-seizure medication that has also been shown to be extremely effective in reducing the frequency and severity of migraines.  It helps with weight loss by increasing the sensation of feeling full, increases calorie expenditure and also makes food taste less appealing.

- Effectiveness - Studies show that 70% of patients lose at least 5% of their body weight, and 48% lose at least 10% of their body weight.

- How do you take it? - One tablet daily in the morning.

- Side Effects - Racing heart, tingling of hands and feet, constipation, dizziness, dry mouth, mental slowing.  Be very cautious if you have hypertension, anxiety, or frequent palpitations.

- Contraindications - Pregnancy, glaucoma, history of reaction to the medication, hyperthyroidism.

- Who should consider taking it? - Those who struggle controlling their appetite.  May be useful if you also suffer from migraines or seizures.

- Score - 8/10.  It is very effective at weight loss, but side effects are extremely common and it is quite expensive.

3.  HCG

HCG is the hormone that is produced in massive amounts during pregnancy.

It has been misused for years as part of the HCG diet.  The HCG diet is a bad diet plan and I would never recommend it because it can severely damage your metabolism by putting you on a severely calorie-restricted diet.

The HCG hormone itself, however, has some properties that could be extremely helpful in weight loss.

- How does it work? - HCG can help normalize testosterone levels in men and estrogen/progesterone levels in women.  It also promotes thyroid activity which increases metabolism.  It also decreases appetite and normalizes food cravings.

- Effectiveness -

- How do you take it? - Use injections (not drops) twice weekly on fasting days for 2-3 months.  DO NOT USE with a severely calorie-restricted diet.

- Side Effects - Water retention, headaches, irritability

- Contraindications - pregnancy

- Who should consider using it? - Those with menstrual irregularities, low testosterone (men), hypothyroidism, and problems with food cravings.

- Score - 7/10 when used correctly.

4.  naltrexone-bupropion (Contrave)

Contrave has been FDA approved for weight loss since 2014.

- How does it work? - Contrave is a combination of 2 medications:  naltrexone and bupropion (Wellbutrin). Bupropion is an antidepressant that blocks the reuptake of dopamine and norepinephrine which reduces appetite and food cravings.  It has been shown to reduce binge eating.  Naltrexone is an opioid antagonist that also reduces appetite and reduces inflammation.

- Effectiveness - About 40% of users lose at least 5% of their body weight in 1 year, about 20% lose at least 10%.

- How do you take it? - A titrating schedule as follows:  1 every morning for 1 week, then 1 twice daily for 1 week, then 2 in the morning and 1 in the evening for 1 week, then 2 twice daily thereafter.

- Side Effects - nausea, constipation, headache, dizziness, insomnia, dry mouth, diarrhea, anxiety, and palpitations are common.  It may trigger seizures if you have a seizure disorder.

- Contraindications - Uncontrolled hypertension, history of seizures, and pregnancy.  Also do not take if you are on chronic opioid pain medications.

- Who should consider taking it? - May be a good option if you also suffer from Hashimoto's or another autoimmune disease.  Especially helpful if you also have chronic pain, depression, or if you deal with food cravings.

- Score - 7/10.  May be expensive.

5.  Appetite Suppressants (phentermine, phendimetrazine, benzphetamin, diethylpropion) -

These appetite suppressants have been around for a long time.  I have never prescribed most of them, but I list them because they are commonly used by some providers, especially in weight loss clinics.

- How do they work? - These medications have a pharmacology similar to amphetamines.  They directly reduce your appetite while simultaneously increasing your metabolic rate.

- Effectiveness - Quite effective at reducing appetite when used correctly and for a short time.  The weight typically returns quickly after stopping the medication.

- How do you take them? - Typically 1 pill every morning.

- Side Effects - anxiety, jitteriness, palpitations, increased blood pressure, insomnia.

- Contraindications - history of amphetamine addiction, uncontrolled hypertension, chronic insomnia.

- Who should consider taking them? - May be helpful to reduce appetite at the beginning of a diet program.  Best if not used every day.  The body becomes tolerant to the effects very quickly, so I will only prescribe it for a month or 2.

- Score - 5/10.  Very effective to reduce appetite, but side effects are common.  Inexpensive.

6.  lorcaserin (Belviq)

Belviq has been available since 2012 for weight loss.

- How does it work? - Belviq activates serotonin receptors in the brain that cause a sense of fullness (satiety).

- Effectiveness - When combined with a diet and exercise program, studies showed about half of the people who took it lost about 5% of their weight (an average of 12 pounds) in the first year.

- How do you take it?  - 1 pill twice daily with or without food.  If substantial weight has not been lost in the first 12 weeks, it is probably not an effective medication for you and should be stopped.

- Side Effects - headache, dizziness, fatigue, nausea, dry mouth, and constipation.  There are concerns about the possibility of heart valve issues with it, but that has not been the case as of yet.  It also caused tumors in animals in some studies.

- Contraindications - Pregnancy or history of reaction to the medication.

- Who should consider taking it? - This drug could be considered if you deal with food cravings and portion control.

- Score - I give it a score of 3/10.  If someone is serious about losing weight, most can lose 5% of their weight with just changing their diet and beginning an exercise program without the risk of taking a medication.  May be expensive.

7.  atemoxetine (Strattera)

Atemoxetine (Strattera) has been FDA approved for treatment of ADHD since 2002.  It has recently been used off label for weight loss.

- How doe it work? - Strattera is a norepinephrine reuptake inhibitor which results in a reduction in appetite and improved cognitive function.  It may also increase energy.

- Effectiveness - No official studies on using it for weight loss.  There is anecdotal evidence of mild to moderate weight loss in the first few months of using it.

- How do you take it? - Typically 1 capsule once or twice daily, usually 40mg daily then increase as needed to a maximum of 100mg daily.

- Side Effects - Nausea, vomiting, diarrhea

- Contraindications - Glaucoma, history of severe cardiac disease, history of sensitivity to the medication.

- Who should consider using it? - Those who need weight loss that also deal with attention and depression issues.

- Score - 2/10 - Patients that take it for ADHD may lose some weight, but it should not be used for the sole  purpose of weight loss in my opinion.

8.  orlistat (Xenical or Alli)

Xenical has been approved by the FDA since 1999 for weight loss.  It is now available over the counter under the name Alli.

- How does it work? - orlistat blocks the enzyme that breaks down fats in your diet.  That undigested fat is then eliminated in your stool.

- Effectiveness - Studies show a weight loss of about 6 pounds in a year.

- How do you take it? - 1 pill 3 times per day with a fat-containing meal.  If you aren't eating fat in that meal, there is not need to take the medication.

- Side Effects - Since it increases the fat in your stool, you can predict the side effects:  abdominal cramps, diarrhea, greasy rectal discharge.  In other words, "Don't trust your farts!"  It may also block the absorption of fat soluble vitamins (A,D,E and K) so they will need to be supplemented.

- Contraindications - Chronic diarrhea or other GI issues.  History of low levels of fat soluble vitamins.

- Who should consider taking it? - No one in my opinion.

- Score - 1/10.  6 pounds in a year is pathetic, especially in light of the common side effects that come with taking it.  Most research has shown that we need good, healthy fats, so taking this medication would be counterproductive.  Carbohydrate reduction is what most of us need, not fat reduction.


There are multiple medications available by prescription to help with weight loss.  Some are quite effective when used appropriately, some are not.

It is important that you study any medication that you may be considering to help with weight loss to make sure that you can use it safely and effectively.  

It is critical that you identify the root issues that have led to your weight gain before starting any weight loss medication.  Without addressing those issues, you will not be successful in your weight loss journey.

Now it's your turn...

Have you ever taken one of these weight loss medications?

What was your experience?  Did you lose weight?  Did you have any side effects?

Leave your questions and comments below.

About the Author Dr. Jeff Whelchel

Dr. Whelchel is a family physician who specializes in functional medicine, especially hormone optimization. He has over 20 years experience in private practice managing patients with various medical issues. His passion is helping patients reach their full potential of wellness and quality of life. He grew up in the Texas Panhandle where he currently lives. He is married and has 3 awesome children.

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