Adderall vs. Phentermine for Weight Loss

Adderall is not meant for weight loss, so don't take it unless your doctor prescribes it for a different condition like ADHD.
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If you're considering weight loss pills, you may be investigating phentermine versus Adderall. But these drugs are intended to be used for very different purposes, and misusing either can jeopardize your health.


In fact, it's not safe or recommended to use either medication unless your doctor prescribes it.

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With that important stipulation in mind, here's what to know about phentermine versus Adderall when it comes to weight loss, including side effects and safety considerations to keep in mind if you're prescribed either drug.


Adderall is not meant for weight loss, per August 2014 research in ​Eating Behaviors​. As a result, don't use this drug to help you shed pounds — only take it if your doctor prescribes it for other conditions like attention-deficit hyperactivity disorder (ADHD) or narcolepsy, per the Mayo Clinic.

Adderall vs. Phentermine: Which Is More Effective for Weight Loss?

Phentermine (also known as it's brand name, Adipex-P) is an FDA-approved, amphetamine-like prescription medication that's used to suppress appetite and promote weight loss, according to the Mayo Clinic.

Adderall is a prescription medication that combines amphetamine and dextroamphentamine to treat conditions like ADHD and narcolepsy, per the Mayo Clinic.

A common side effect of Adderall is weight loss, per the Mayo Clinic, so this medication is sometimes used off-label to help you shed pounds. However, it can be harmful to use drugs without the prescription and supervision of your doctor — in other words, taking Adderall for weight loss is not typically safe or recommended.


Phentermine is not like Adderall, meaning you can't take phentermine for ADHD. Its intended purpose is for weight loss, and it's been through rigorous FDA testing to support this use. Adderall, on the other hand, has only been approved to treat other conditions, and as a result, there may be unknown risks associated with using Adderall for weight loss.

Here's what Adipex does for weight loss: According to an April 2014 review in ​JAMA​, adults with obesity who took phentermine/topiramate (along with making lifestyle changes like eating a balanced diet and exercising) experienced up to 9 percent more weight loss than those who took a placebo medication.


The takeaway: Phentermine is the better choice if your goal is to shed pounds, and can be an effective prescription treatment if you have severe obesity.


Other Medications

Perhaps you're considering other medications for their weight-loss effects — for instance, you may be weighing phentermine versus Ritalin (another stimulant used to treat ADHD and narcolepsy) or the K 25 pill or diethylpropion (other appetite suppressants) versus Adderall.

But again, it's only recommended to use these drugs for their FDA-approved uses with a prescription from your doctor. Do not take the medications otherwise.

Safety Considerations

Phentermine and Adderall can have side effects — here are some to keep in mind before taking either medicine as prescribed:


Side Effects of Adderall

According to the Mayo Clinic, common Adderall side effects include:

  • Anxiety
  • Dry mouth
  • Lack or loss of strength
  • Stomach pain
  • Weight loss

These side effects typically don't require medical attention, and should go away on their own as your body adjusts to the medication. However, you should seek medical care if you experience any of the following issues:


  • Bladder pain
  • Bloody or cloudy urine
  • Frequent urge to urinate
  • Difficult, burning or painful urination
  • Fast, pounding or irregular heartbeat
  • Lower back or side pain

Adderall is also one of the most commonly misused drugs, according to the Mayo Clinic. Taking Adderall for weight loss without a prescription is one example of this. And misusing the medicine can lead to a dependence or addiction.


It's also important to avoid this medicine if you're already taking (or have recently stopped taking) a class of antidepressants called MAO inhibitors, per the Mayo Clinic. Mixing the two could lead to more side effects.

Adderall and Your Gallbladder

There's no evidence to suggest that Adderall commonly interferes with gallbladder function. However, it can affect your bladder and cause pain or abnormal urination, per the Mayo Clinic.

Side Effects of Phentermine

Adipex can also cause side effects, per the Mayo Clinic. The most common are:


  • Increased heart rate
  • Tingling or prickling feeling in hands or feet
  • Dry mouth
  • Sleeplessness
  • Nervousness
  • Constipation


It's also best to avoid this medication if you have any of the following conditions, according to the Mayo Clinic:

Like Adderall, you should also avoid phentermine if you're taking or have recently stopped taking an MAO inhibitor, per the Mayo Clinic.


Talk to your doctor about any preexisting conditions or medications you take before starting any new prescription to make sure it's safe for you.

Should You Take Phentermine or Adderall for Weight Loss?

In the debate between Adipex versus Adderall for weight loss, Adipex wins because it is FDA-approved to help treat obesity.

But if you don't have severe obesity or your doctor doesn't recommend phentermine, you may not need to consider using Adderall versus Adipex at all. Instead, talk to your doctor about losing weight through lifestyle changes recommended by the National Health Service, including:

  • Eating a balanced diet
  • Getting plenty of fiber
  • Exercising regularly
  • Staying hydrated
  • Cutting back on alcohol

Can You Take Phentermine and Adderall at the Same Time?

Though there are no known interactions between the two drugs, don't take both at the same time (or any other medications, for that matter) without talking to your doctor first, per the Mayo Clinic.




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