Key takeaways
Phentermine is an appetite suppressant that’s FDA approved for the short-term treatment of obesity.
You can get phentermine in person or online, but a medical professional must prescribe it.
Phentermine is safe for most people, but it can exacerbate certain underlying medical conditions, and it has the potential for abuse.
Phentermine HCl is an appetite suppressant that can help you lose weight. It’s approved by the U.S. Food and Drug Administration (FDA) to treat obesity in the short term and is meant to be combined with exercise, calorie reduction, and behavioral modifications. Phentermine is sold as a prescription medication under the brand names Adipex-P and Lomaira. Phentermine can also be sold generically, however, it is not available without a prescription.
RELATED: Overweight and obesity statistics 2024
Research has found that phentermine effectively reduces your appetite and aids in weight loss. In one study, the average weight loss among people taking phentermine was over eight pounds. A separate clinical trial showed that obese study participants in Korea lost 5-10% of their original body weight.
Phentermine requires a prescription from a licensed healthcare professional to purchase at your local pharmacy. This usually means that you need an in-person consultation with a medical professional who can write you a prescription. It may also be possible to utilize a weight loss clinic or a telehealth provider.
Learn more here: Can you get phentermine over the counter?
Where can I get phentermine?
Where can I get phentermine pills? You will need a prescription, but once you have one, you can usually get phentermine at your local pharmacy.
Phentermine is usually covered by insurance, says Meghan Garcia-Webb, MD, who is triple board-certified in internal medicine, lifestyle medicine, and obesity medicine. However, some insurance companies will only cover it for up to 12 weeks. “This is largely a historical remnant because phentermine was originally FDA-approved in the 1950s for short-term use,” Dr. Garcia-Webb explains.
Although phentermine is FDA-approved for short-term use, many healthcare professionals will prescribe it off-label for longer-term use. “Typically these days, it’s best to consider all weight medications for lifelong use because when patients stop taking them, in general, they stop working,” Dr. Garcia-Webb says.
What should you do if insurance does not cover the longer-term use of phentermine? “Patients can pay out of pocket,” Dr. Garcia-Webb suggests. “Since it is available as a generic, it can generally be quite affordable.”
Let’s examine some of the places where you may be able to get a prescription for phentermine.
RELATED: What obesity treatments does insurance cover?
Local pharmacies
You can typically obtain phentermine from a nearby pharmacy if you’ve been prescribed it. You don’t need to go to a specialty pharmacy to get phentermine.
“Most pharmacies keep phentermine in stock, but its availability sometimes fluctuates because of supply shortages,” says Diala Alatassi, MD, a double board-certified internal medicine and obesity medicine specialist at Endeavor Health. “It may be smart to contact the pharmacy beforehand to ensure its availability,” she advises. “It’s worth noting that there may be occasions when phentermine is temporarily unavailable due to back orders resulting from high demand.”
Some insurance plans may require proof of medical need before determining coverage for phentermine. If your insurance company won’t pay for phentermine or will only pay for it for a limited number of weeks, you have options. Generics are an excellent phentermine alternative. Experts agree that the generic forms of phentermine are just as effective as the brand versions, and the generic versions are affordable for most people regardless of insurance coverage. The generic version of phentermine costs about $51 per month, but this can be reduced to as little as $5 per month with a SingleCare discount card.
Weight loss centers
Weight loss centers offer support so that you can make positive lifestyle, diet, and exercise changes to aid your weight loss journey and reach your goals. These may be brick-and-mortar weight loss centers or online clinics. Some weight loss centers have licensed physicians on staff who can write prescriptions for phentermine and provide medical advice for weight loss.
Dr. Alatassi recommends that when getting a prescription for phentermine at a weight loss center or clinic, you should ensure that you are receiving thorough care and are screened carefully before the medication is prescribed. “It’s crucial to be cautious regarding where you seek care,” she says. “A doctor should thoroughly review your medical history to determine if phentermine is appropriate for you.” This will ensure that phentermine is prescribed safely. You should also make sure the health care provider is aware of any dietary supplements or other prescriptions you are taking.
RELATED: 9 benefits of weight management
Buy phentermine online
There are many online pharmacies these days, and it can be hard to tell which ones are legitimate and which ones may be fake. As such, you need to be cautious if you are looking to buy phentermine online.
“There are multiple ways to get medications online,” Dr. Alatassi says. “Since phentermine is a controlled substance, you need to be cautious and ensure that you are purchasing from a reputable and licensed online pharmacy if you have to.” She says that you should avoid purchasing medications from unauthorized or suspicious websites. Often, online med-spas sell counterfeit or unsafe products, so she suggests that you should be aware of those.
The FDA offers tips on how to choose a legitimate online pharmacy. Here’s their advice:
- Pick pharmacies that require prescriptions from a doctor
- Look for pharmacies that share a U.S.-based physical address and phone number
- Make sure the pharmacy has licensed pharmacists on staff
- Ensure that the pharmacy is licensed by its state’s Board of Pharmacy
Do you have to have a prescription for phentermine?
Yes, you do need a valid prescription from an authorized prescriber to obtain phentermine. Phentermine is a prescription medicine with some potential risks and side effects, and it is important that a healthcare provider oversees your weight loss journey and ensures your continued safety while taking the medication.
How to get a prescription for phentermine?
The best way to get phentermine is to visit a healthcare provider that you know and trust and get a prescription. Dr. Garcia-Webb says that this could be a local healthcare provider or a physician you meet with virtually. “Phentermine is not the right medication for every person, and you need a physician who is comfortable with these medications and can walk you through the pros and cons of the medication,” she says.
Dr. Alatassi recommends first contacting your primary care physician or family practitioner. “If they do not have the expertise, ask for a referral to an obesity medicine specialist,” she says. “These healthcare professionals have the appropriate training, they should have obesity medicine American board certification, and they can determine if phentermine is a suitable option for you.” Remember, successful weight loss plans will include lifestyle modifications that address dietary changes and increased exercise. While at your appointment, discuss all of your weight loss goals to ensure a comprehensive plan for success.
RELATED: Phentermine alternatives: What can I take instead of phentermine?
Safe use of phentermine
Phentermine is generally a safe and effective way to lose weight on a short-term basis. But, it needs to be used with caution. Phentermine is a central nervous stimulant and works in a similar way as amphetamine, stimulating the release of norepinephrine and epinephrine. It’s considered a Schedule IV controlled substance, which means that it has the potential to be abused. This is why it’s important to get phentermine from a trained medical professional and why you should only take phentermine in the dosage and frequency prescribed by your physician.
Phentermine dosage
Phentermine comes in two different forms: tablets and extended-release capsules. Most physicians recommend that you take phentermine once a day in the morning, either 30 minutes before breakfast or one to two hours after eating. Sometimes phentermine is prescribed twice daily, evenly spaced throughout the day, and taken before a meal.
Precautions when using phentermine
Although phentermine is safe for most people, there are some precautions to remember. “It is important for patients to be monitored by their physician while taking this medication, as it can increase blood pressure and heart rate,” says Dr. Garcia-Webb. “Usually, I will ensure there is an EKG done before starting and then updated yearly at least.” Persons with a history of thyroid problems, bronchial asthma, or seizure disorders may not be good candidates for phentermine use. Be sure to share all health conditions with your prescriber.
People who should not take phentermine include:
- Anyone who has uncontrolled high blood pressure, uncontrolled hyperthyroidism, a history of heart disease, glaucoma, or a history of substance abuse
- Individuals who are pregnant, planning to become pregnant, or breastfeeding
- People who take monoamine oxidase inhibitors (MAOIs)
Though not generally dangerous, phentermine can have side effects, including:
- Increased heart rate
- Increased blood pressure
- Dizziness
- Trouble sleeping
- Agitation and anxiety
- Heightened feelings of euphoria
- Dry mouth
- Tremors
- Headaches
- Digestive upset
- Itchiness
- Sexual side effects, such as impotence and changes in libido
Overdosing on phentermine is not common, especially if you follow the dose recommendations and your doctor’s instructions. However, you should be aware of the signs of a phentermine overdose. Please contact emergency services if you have any of the following signs of a phentermine overdose:
- Confusion
- Behavior changes
- Hallucinations
- Acute panic
- Rapid breathing
- Excessive tremor
- Intense restlessness
- Involuntary muscle movements and muscle weakness
- Sweating
- Nausea, vomiting, and diarrhea
While you are taking phentermine, it is important to immediately report to your healthcare provider if you experience serious side effects, including any allergic reactions, new eye symptoms or vision changes, worse anxiety or worse depression as compared to before you started phentermine, or suicidal thoughts. Seek medical attention immediately if these occur.
The bottom line? Phentermine is an appetite suppressant that has been around for decades and is a good choice for many folks who are looking for a medication to help manage obesity. A successful weight loss plan will include a healthy diet and exercise, too. Although you can get phentermine locally, online, or at certain weight loss clinics, you always need a prescription.
- Pharmacologic therapy for obesity, StatPearls (2022)
- Postmarketing surveillance study of the efficacy and safety of phentermine in patients with obesity, Korean Journal of Family Medicine (2013)
- Effects on weight reduction and safety of short-term phentermine administration in Korean obese people, Yonsei Med J (2006)
- Considering an online pharmacy?, U.S. Food and Drug Administration
- Topiramate and phentermine, StatPearls (2023)
- LOMAIRA – phentermine hydrochloride tablet, DailyMed, National Library of Medicine (2023)
- Phentermine, MedlinePlus (2017)
- Phentermine hydrochloride – phentermine hydrochloride tablet, DailyMed, National Library of Medicine (2012)