Phentermine for Weight Loss: Cost, Results, and Side effects

According to the CDC, between 2015 and 2016 obesity affected 39.8% of US adults or 93.3 million people. Phentermine is a medication that sparks interest in many who are looking to shed those pounds. This article will cover important details to be aware before ultimately taking the plunge into a weightloss journey with phentermine.

Phentermine is a medication to assist with weight loss in patients who are overweight or obese. It is a stimulant that curbs appetite and boosts metabolism to help burn excess calories consumed and is commonly prescribed at medical weight loss clinics.

Phentermine’s cost, results, and side effects will be covered in detail to help guide you through this decision, allowing you to weigh your options so that in the end you see those results.

Losing weight is hard and there are countless supplements and medications to assist you on your journey. With internet site after internet site it is hard to know what to trust and where to start.

This article will be a concise jump point to help you figure out some key information about phentermine, as well as, some alternative paths you could venture down.

How much does phentermine cost without insurance?

Phentermine is typically not covered by most insurances. As such, if you are prescribed phentermine by your doctor you will have to pay the full cost of the prescription out of pocket.

Phentermine is available in both tablets and capsules in several different dosages. The most common dosage is the generic for Adipex-P which is 37.5mg.

In most cases the price between the tablets and capsules varies, with the capsules generally being more expensive. However, this can vary at your local pharmacy so it is important to talk with your pharmacist about out of pocket prices between the two if you are not using insurance.

The out of pocket cost for phentermine averages around $35 for thirty 37.5 mg tablets or capsules, which is the most common dosage. Prices do vary for each pharmacy, some may be as high as $50 for a one month supply.

Thankfully, there are tools to use to find the cheapest price for phentermine in your local area. These tools include prescription discount cards, the best of which from my experience is Singlecare. Make sure to also check out my other recommended prescriptions discount cards and services to see if any of those get you a better deal since no single discount card is the best for every drug.

The absolute best prescription discount card to use to buy phentermine is Singlecare. You can get a one month’s supply for under $10 at CVS or Walgreens or as low as $5.57 at Walmart as of the date of this article being published. Keep in mind medication prices can fluctuate on a daily basis so download the Singlecare app now or check the current discounted price for phentermine now!

If you live in a rural community and it’s a long drive for you to go to a pharmacy you can have your phentermine delivered via mail by using, the only online pharmacy I recommend.

Keep in mind phentermine is categorized as a schedule IV medication, so it is a controlled substance. This means you cannot get more than your allotted amount as specified by your physician within a specified time frame.

If a medication has abuse potential or can develop dependence, it is listed as a controlled substance. This is a way to help regulate the medication so it is limited and there is not an excess of supply that could end up in the wrong hands to be abused.

Discounted prices comparison

Here is a comparison between some discounted prices of phentermine. Four different discount services are compared Singlecare, Blink Health, GoodRx, and GoodRx Gold.

Each site has advantages and disadvantages, with different pharmacy availability and varying prices. They are all discount coupon price websites and are available without a membership fee except GoodRx Gold which is $5.99 per month.

I won’t discuss the advantages or disadvantages of each of these services in this article. You can read my reviews of each to get more detailed information.

Discount Site 30 Tablets
Dosage: 37.5 mg
30 Capsules
Dosage: 37.5 mg
SinglecareLowest Price:
Walmart $5.57

Walgreens $9.37
CVS $14.85
Lowest Price:
CVS $12.82

Walmart $12.93
Walgreens $18.87
Blink HealthBlink Everyday
Low Price: $11.64

Blink Smart Deal: $8.88
Blink Everyday
Low Price: $14.12

Blink Smart Deal: $11.35
GoodRxWalmart $13.09
CVS $16.40
Walgreens $17.91
Other local pharmacies
range from $8.12-$14.05
Walmart $15.95
CVS $17.40
Walgreens $16.91
Other local pharmacies
range from $14.32-$17.60
GoodRx GoldCVS $14.00
Limited network of
pharmacies. No other
major chain pharmacy
participates in this
CVS $14.00
Limited network of
pharmacies. No other
major chain pharmacy
participates in this program.

*Prices are accurate as of the date of publishing. Prescriptions prices change frequently.

Should I buy phentermine online?

If you are thinking about buying phentermine online there are some key factors to verify before going through this route. Look for the VIPPS accreditation and .pharmacy domain to be safe and verify the websites through NABP’s list of valid websites.

Look for these images to confirm you are on a legitimate online pharmacy website

Even if you see these symbols it is good to double check through NABP that you are using a legitimate online pharmacy site. It is an extra step but and important step to make sure something as important as your medication is held up to a certain standard.

To double check VIPPS accreditation here is the list of valid websites.

To double check .Pharmacy legitimacy here is the list of valid websites.

This is important because purchasing a medication online through a non-government regulated site is illegal.

This does not mean you can’t buy or use discount sites to purchase phentermine, but you should make sure it is a verified, legitimate site first.

Purchasing phentermine through a website that is not being monitored or meeting certain credentials means you could end up with medication that is not what it claims to be.

It could be mixed with another substance or not contain what you thought was in it at all. This is a huge risk to take on something that could be costly to your health.

There are many websites you can use to cut costs on prescription medications. However with a study showing over 96% of online pharmacies are not legitimate it should be your top priority to be more safe than sorry with your health. It’s really best to get phentermine from you local pharmacy instead of online.

Your doctor is monitoring the effects of your medication in the assumption that you are receiving the correct medication and dosage unless they are told otherwise. So it is important to purchase through legal websites or your local pharmacy to ensure the best care.

Why not to buy phentermine online

Phentermine is a controlled substance so it is illegal to purchase this medication without a valid prescription. Unless you are purchasing from a valid online pharmacy the medication you receive could be something detrimental to your health.

In 2001, Ryan Haight, a teenager purchased Vicodin online and fatally overdosed. The Ryan Haight Online Pharmacy Consumer Protection Act of 2008 was passed to ensure that controlled substances could not be dispensed, distributed, or delivered without at least one in-person doctor’s visit.

The Federal Drug Administration regulates prescription medication and requires necessary tests to ensure the quality of the medication. Without their control there is no guarantee you are actually receiving what you are paying for.

In the off chance that what you purchase is actually phentermine, the side effects you can have should be regulated and monitored by a physician. Without their knowledge that you are on the medication, they cannot ensure that the other medicines you are on is not going to interact or affect the phentermine you are on.

The Ryan Haight Act has been in the news recently as there is a drive to allow controlled substances to be prescribed through telecommunications. The term telemedicine is the fusion of these telecommunications and medical practices. Ultimately the aim is to assist with the opioid-epidemic and allow more online services to expand to increase the reach of patients they can assist.

How effective is phentermine?

Studies show that most people that complete a 3 month course of phentermine lose up to 15 pounds.

It is important to not look at phentermine as the miracle diet pill. It is something to help in addition to diet and exercise. It is something that is used to aid in weight loss and not simply a fix all solution.

Phentermine can have unpleasant side effects that can happen and should be discussed with you by your doctor or pharmacist. Medication affects people differently so a side effect someone else experiences may not be something you experience. So do not let this discourage you if this is something your doctor believes is a right fit for you.

When googling phentermine you can find the good, the bad, and the ugly when it comes to reviews. There are people who have benefited from the medication, as well as, people who have had negative side effects leading to discontinuation.

Either way you spin it, if phentermine is something that will help you lose weight and may have an effect on your quality of life or even cut back on weight related health conditions it may be worthy option.

It is important to be aware of the side effects and express any concerns to you doctor or pharmacist. They can help guide you of any concerns or negative side effects as to what action should be taken or the next steps. If they cannot be reached and you are experiencing negative side effects from any medication it is important to seek prompt medical treatment.

What’s the deal with “herbal phentermine”?

In 2006 a product listed as a “herbal phentermine” was taken off the market after the company was contacted by the FDA. The ingredients they listed as having the desired weight loss effects were L-Carnitine, Green Tea extract, Alpha Lipoic Acid, and black pepper extract.

These ingredients appear scattered in a lot of the supplements available over the counter currently. Today herbal phentermine is mostly alternative “natural” ingredients that are claimed to have these weight-loss effects.

Many of these alternative medications have not been evaluated by the FDA and their weight loss and other claims have not been verified. That being said, if you are looking for a supplement alternative, and are not ready to take the leap to phentermine and its possible side effects this may be a great place to start. It is important to ensure you are not allergic or have a contraindication to the ingredients so you should discuss with your doctor before taking any of these supplements.

I’m taking phentermine what should I know?

What time of the day should you take phentermine?

Phentermine should be taken in the morning or 30 minutes before meals as specified. It’s dosing is different and depends on the most effective method for you in order to see the best weight loss potential.

The breakdown is as follows:

Phentermine 37.5 mg capsule

  • Once Daily:  taken as a single dose once daily before breakfast or 1 to 2 hours after breakfast

Phentermine 37.5 mg tablet

  • Once daily: taken as a single dose once daily before breakfast or 1 to 2 hours after breakfast
  • Once or twice daily: Some patients ½ a tablet is sufficient or it is best for them when taking ½ a tablet twice a day

Phentermine 15 or 30 mg dosage:

  • Usual dosage is 15 mg to 30 mg as prescribed by physician taken by mouth 2 hours after breakfast

Phentermine 8 mg dosage:

  • Dosed up to 3 times daily 30 minutes before meals

Ultimately you should take as directed by your physician. If you have any questions about how to take the medication or when to take the medication be sure to double check with your doctor or pharmacist.

How long do you take phentermine for?

Phentermine is used for a limited time span in with the goal to speed up weight loss. It should be used in combination with a healthy diet and exercise. This medication can be habit forming and should be taken as directed and is ultimately based on your results and tolerance of the medication. Most patient’s length of treatment is 3 to 6 weeks, and should not exceed 3 months.

How much weight can you lose on phentermine?

Unfortunately, this is not the miracle to weight loss and it necessary to include a low calorie diet and exercise to ensure you see results. It is not the sole answer but is an aid to achieve weight loss. With these conscientious decisions you can achieve your normal weight, if these are not followed you could see 0 to 15 lbs. in weight loss depending on how much you have to lose.

So it is important to combine phentermine with exercise and a healthy diet and sustain the changes once you are off the medication.

What is the most effective way to lose weight with phentermine?

The most effective method to increasing your weight loss with phentermine is to combine with diet and exercise. Phentermine works to reduce your appetite and boosts your metabolism so you burn more calories.

During this time your metabolism is boosted so once you stop you have the possibility of gaining the weight back as your metabolism is stabilized and ultimately slowed as its new normal. What this means is phentermine should not be taken long term and it is important to still consume food but you should substitute low-calorie foods.

In an article Dr. Westin Childs discusses taking the medication more sporadically throughout the week instead of daily. You can see how this would have a less drastic effect on your metabolism and ultimately better results once you stop taking phentermine.

Keep in mind, it is important to take the medication as prescribed by your physician, and any adjustments you are thinking about changing should be discussed prior to making the switch.

Side effects associated with Phentermine

  • Gastrointestinal: diarrhea, constipation, vomiting
  • Upper respiratory system: dry mouth, unpleasant taste

Serious side effects to seek immediate treatment for

  • Cardiovascular: heart palpitations, increased blood pressure, chest pain
  • Central nervous system: tremor, dizziness, restlessness, insomnia, difficulty doing exercises that you had previously been able to do
  • Respiratory: shortness of breath
  • Extremities: swelling of legs and ankles

Other side effects are also possible and should be discussed with your physician or if it is a serious side effect you are experiencing you should proceed to your nearest emergency room. Additionally serious side effects can be reported through the FDA’s MedWatch Adverse Event Reporting program at or by phone at 1-800-332-1088.

It is important to consider what is ultimately best for you. Physicians and pharmacist are available and ready to help if you have questions regarding your medications and can assist if you are curious about various supplements. It is important to discuss with you doctor before starting any supplements to verify they are safe for you and will not interfere with other medications you may be taking. Just because it is a “natural” supplement does not always mean that it wont have an effect on something else you are taking or a condition you may have. If you are interested in taking phentermine speak with your doctor to discuss if this is the right option for you.


As a practicing community pharmacist in his home state of Michigan, Joe (AKA TheFrugalPharmacist) is always on the lookout for new information and ways to ensure you can afford your medications and don't get ripped off in America's complicated world of healthcare.

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