Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to weight loss medication.
Adipex-P is an FDA-approved prescription weight loss medication.
Adipex-P is the brand-name version of the drug, and the generic version is called phentermine. These two terms refer to the same active drug ingredient so we'll use them interchangeably throughout this article.
But is Adipex-P proven to cause weight loss in research studies? Does it have any potentially dangerous side effects? How do real users rate and describe the effects of the drug? And is the generic version cheaper?
In this article we’ll answer all of these questions and more as we analyze medical studies on Adipex-P to determine if the drug is likely to be effective for weight loss.
We'll discuss side effects, feature unsponsored patient reviews and document whether the generic version of the medication is a better value.
Is Adipex-P Proven to Work?
The effects of Adipex-P on weight have been studied extensively in clinical trials.
A 2008 clinical trial tested whether Adipex-P could cause weight loss in obese patients. After 14 weeks, nearly 90% of the Adipex-P patients lost 5% or more body weight, and 50% of Adipex-P patients lost 10% or more body weight.
A meta-study published in the Obesity journal examined the long-term effectiveness of Adipex-P.
The researchers tracked results from patients using the drug continuously for up to 24 months. The group taking Adipex-P for over 12 months lost 7.4% more weight than a control group that was taking placebo pills.
A 2014 medical review analyzed data from six clinical trials on Adipex-P. The researchers reported a statistically significant weight loss result in all trials. The average weight loss was 13.91 pounds, and the studies ranged from 2-24 weeks.
Based on the available research, we consider Adipex-P to be effective for treating obesity.
But does the drug cause side effects? We'll answer that question in the next section of this article.
Does Adipex-P Cause Side Effects?
Adipex-P does have a risk of side effects which is outlined in both medical studies and on the drug's label.
A medical review found the following side effects to be the most common from Adipex-P use: anxiety, palpitations, headache and insomnia.
Adipex-P's FDA label shares a warning about using the medication in combination with other weight loss treatments, whether prescription drugs or over-the-counter (OTC) drugs, for more than "a few weeks."
The safety of using Adipex-P in conjunction with other treatments has not been proven, and the drug manufacturer recommends against it.
This drug label is free of a "black box" warning, which is a warning of side effects can be life-threatening which is required by the FDA when appropriate. This suggests that Adipex-P may be safer than some other prescription medications which do carry a black box warning.
Real People Review Adipex-P
One of the most popular YouTube reviews of Adipex-P comes from a creator named "Katie G." who shares before-and-after images of her 70 pound weight loss journey using Adipex-P.
A YouTube creator named Denai Lacole claims to have lost 20 pounds from taking Adipex-P:
Adipex-P Dosage
Adipex-P is typically prescribed at a once-daily dosage of 37.5 milligrams (mg). Some patients are prescribed a half-dose, which equals 18.75 mg daily.
The benefit of a lower Adipex-P dose is that it may reduce the risk of side effects. The drug label even states the following: "dosage should be individualized to obtain an adequate response with the lowest effective dose."
Less weight loss can be expected from a lower dose, but so long as the weight loss is consistent, a doctor may keep their patient on the lower dose for safety reasons.
Should I Take the Generic Version?
Patients are often curious about whether they should take the generic or the branded version of a drug, given that both contain the same active ingredient(s).
As we suggested in our phentermine reviews article, the generic may be the better option.
A meta-study published in the PLOS Medicine journal compared the effectiveness of generic and branded drugs. The study authors analyzed data from over 2 million patients and found generic and branded drugs to be equivalently effective.
Generic drugs can be cheaper than brand-name drugs, so we would recommend that patients speak to their doctor about phentermine rather than Adipex-P.
How Does Adipex-P Work?
Adipex-P is an appetite suppressant. When patients take Adipex diet pills, the level of a neurotransmitter called norepinephrine increases significantly in their brain.
A medical review documents a potential mechanism of action of Adipex-P: the drug appears to inhibit expression of a chemical compound in the brain called neuropeptide Y which sends hunger signals to the body. However, this needs to be confirmed with further research.
Adipex-P is chemically similar to amphetamine, and can cause similar effects to the body such as central nervous system stimulation and increased heart rate and blood pressure.
The medical review linked above states that the medication causes a "continuous fight-or-flight response in the body." This is why it may cause anxiety in some patients.
Is Adipex-P Available OTC?
Adipex-P is not currently available over-the-counter (OTC). The medication requires a prescription and cannot be legally purchased in a drugstore or online without one.
Typically, pharmaceutical drugs are not available OTC, and especially so for drugs in categories like weight loss that have the potential for abuse.
Adipex-P can be purchased online with a prescription. Amazon has a service called Amazon Pharmacy that allows patients to contact pharmacists virtually, but it's unclear to us whether a patient will still need to go to a local doctor for Amazon's service to work.
We recommend avoiding any merchant, online or otherwise, that sells Adipex-P without requiring a prescription. This may increase the risk of purchasing fraudulent medication which can be harmful.
Real Patients Review Adipex-P
Adipex-P has been reviewed 600 times on Drugs.com, which is an online resource for patients to publish personal reviews of medication they've been prescribed.
The average rating for Adipex-P is 8.9/10, which is the highest average rating of any prescription drug that we've reviewed at the time of updating this article.
The top positive review is from a user named "SheilaD" who claims that the drug is effective for weight loss and had minimal side effects:
"Started Adipex 11 days ago, weighed myself today and have lost 11 pounds."
The top negative review is from a user named "SJ" who claims that the drug is ineffective and expensive:
"Teva changed adipex formula (no blue dots anymore) and although they say that was the only change, these are worthless. Not only did the cost go up, but they are ineffective. I spent $600 for 90 supply!!! I have to take 3 whole pills to get any effect whereas the pills with blue dots 1 to 1.5 was sufficient."
Our Clean Weight Loss Picks
Ceylon cinnamon was described as "an effective anti-obesity agent" in a 2022 meta-analysis. The study authors concluded that effects were greater at doses at or over 3 grams daily.
Illuminate Labs Ceylon Cinnamon Extract is our standardized Ceylon cinnamon supplement which is third-party tested to ensure purity and potency.
Dietary fiber was shown in a medical review published in The Journal of Nutrition to cause 16 pounds of weight loss in 6 months when combined with moderate caloric restriction (750 calories per day below baseline).
MBG Organic Fiber Potency+ is our top fiber pick because it's certified organic, provides 7 g of fiber per serving and costs under $1.85 per serving at the time of updating this article.
Both of the products mentioned in this section are entirely free of additive ingredients that we consider to be unhealthy.
We are not suggesting that the products referenced in this section are as effective as Adipex-P, or any other FDA-approved weight loss medication. Rather, we're sharing options that patients with an aversion to pharmaceutical medication may wish to speak to their doctor about.
Can I Drink While on Adipex-P?
Drinking alcohol while taking Adipex-P may cause harmful interactions and is inadvisable. The drug's FDA label states that "concomitant alcohol use may result in an adverse drug reaction."
The label also includes "usage with alcohol" in a "Warnings and Precautions" section.
Given that even moderate alcohol use can cause health risks when combined with Adipex-P use, we would strongly suggest that patients are honest with their doctor about their alcohol intake and ability to quit before being prescribed this drug.
Patients unable to quit alcohol may benefit from speaking with their doctor about alternative weight loss medications that don't have an interaction with alcohol.
Adipex-P vs. Adderall
Some patients compare Adipex-P and Adderall for weight loss, because many individuals use Adderall recreationally and have noted weight loss as a side effect.
Adderall is an amphetamine, which means it's a stimulant that increase calories burned at rest and can cause weight loss.
Adderall is not approved by the FDA for weight loss, so using it for this health outcome would be an "off-label" use, which may be less safe than using drugs as intended according to their FDA label.
We would recommend that patients interested in a pharmaceutical approach to weight loss speak with their doctor about Adipex-P instead of Adderall.
