April 15, 2024

Phentermine vs Adderall: Key Differences You Need to Know for Weight Loss

Dr Bosah Chike avatar
Dr Bosah Chike
Dr Victoria Abbey avatar
Medically reviewed BY
Dr Victoria Abbey
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Navigating the landscape of prescription drugs for weight loss, you'll likely encounter Phentermine and Adderall, each with its distinct characteristics and FDA approvals. Phentermine, a generic prescription drug, is FDA-approved specifically for weight loss when paired with diet and exercise, designed for short-term use in individuals aged 17 and older. On the other hand, Adderall, a brand-name medication, falls into the category of central nervous system stimulants and, while not FDA-approved for weight loss, is widely recognized for its effects on alertness, concentration, and focus.

The dilemma of choosing between Phentermine vs Adderall for weight loss involves understanding their similarities as controlled substances, with Phentermine classified as a Schedule IV drug and Adderall, bearing a more severe Schedule II classification due to its high potential for abuse. Both medications come in differently formulated capsules and carry risks of side effects and dependency, underlining the importance of consultation with a healthcare provider for an informed decision that aligns with your health goals and medical history.

Phentermine Overview

Phentermine is a prescription medication specifically approved by the FDA for weight loss when combined with a diet and exercise regimen. It belongs to the class of drugs known as anorectics, which are chemically similar to amphetamines. As an appetite suppressant, phentermine works by influencing the central nervous system to decrease hunger through neurotransmitters like norepinephrine, dopamine, and serotonin.

Key Attributes of Phentermine:

  1. Usage and Dosage: Typically prescribed for short-term use, up to 12 weeks, phentermine is available in various forms including tablets, capsules, and extended-release capsules. It is generally taken once or twice a day before meals to effectively manage obesity.
  2. Drug Interactions and Side Effects: Phentermine interacts with 194 different drugs, with 43 of these interactions classified as major. Potential side effects range from increased blood pressure and palpitations to more severe effects like angina and swollen legs. It is crucial to avoid alcohol and monitor for signs of serious side effects during treatment.
  3. Contraindications: Not suitable for individuals with glaucoma, an overactive thyroid, or those who are pregnant, as it is classified under Pregnancy Category X due to risks of birth defects. It should also not be used within two weeks of taking Monoamine Oxidase Inhibitors (MAOIs).

Phentermine's role in weight management is significant, offering an energy boost by increasing fatty acid and glucose levels, which aids in breaking down stored fat. However, it's essential to pair the medication with lifestyle changes like a reduced-calorie diet and regular exercise for optimal results.

Phentermine: How It Works

Phentermine operates primarily by diminishing your appetite, making it easier for you to reduce calorie intake without feeling deprived. This effect is achieved through its action on the central nervous system, similar to that of amphetamines, which stimulates the release of neurotransmitters like dopamine and serotonin. These neurotransmitters not only enhance mood and mental alertness but also play a crucial role in appetite suppression and reducing fatigue.

Detailed Mechanism:

  1. Neurotransmitter Release: By releasing neurotransmitters such as dopamine and serotonin, phentermine helps improve your overall mood while simultaneously suppressing your appetite.
  2. Energy Production: Phentermine aids in breaking down stored fat by increasing levels of fatty acids and glucose, which leads to enhanced energy production. This can be particularly beneficial if you are following a low-calorie diet for weight loss, as it helps combat the usual fatigue associated with dieting.
  3. Leptin Levels: Additionally, phentermine may indirectly boost leptin levels in the body. Leptin is a hormone responsible for signaling fullness to the brain, thus helping you feel satisfied with smaller portions of food.

This combination of effects not only assists in immediate weight loss by reducing appetite and increasing energy levels but also supports long-term weight management by altering how your body senses satiety.

Adderall Overview

Adderall, a well-known prescription medication, is primarily utilized for managing attention deficit hyperactivity disorder (ADHD) and narcolepsy. This drug combines two active ingredients, amphetamine and dextroamphetamine, which are central nervous system stimulants that help enhance focus, attention, and alertness. Available in both immediate-release and extended-release forms, Adderall allows for dosing flexibility that can be tailored to the needs of the patient, with dosages ranging from 5 mg to 30 mg.

Key Information on Adderall:

  1. FDA Approval and Uses: Adderall is FDA-approved specifically for the treatment of ADHD and narcolepsy, aiding in increased attention and wakefulness.
  2. Schedule and Regulation: It is classified as a Schedule II controlled substance, reflecting its high potential for abuse and dependence, which necessitates careful monitoring by healthcare providers.
  3. Pregnancy and Drug Interactions: Not recommended for use during pregnancy (Category C) and interacts significantly with other medications, with 37 major drug interactions noted, which could pose health risks if not managed properly.

Serious side effects associated with Adderall include cardiovascular issues, psychological reactions such as depression and mania, and other severe conditions like seizures and speech difficulties, underscoring the need for strict medical supervision when using this medication.

Adderall: How It Works

Adderall, a combination of amphetamine and dextroamphetamine, is primarily prescribed for ADHD and narcolepsy, enhancing focus and alertness. Here’s how it functions:

  1. Neural Activity Increase: It boosts neural activity in the central nervous system, which elevates energy levels, enhances focus, and reduces restlessness and fidgeting.
  2. Neurotransmitter Release: Adderall triggers the release of dopamine and norepinephrine, neurotransmitters that influence mood, attention, and concentration. This action helps increase alertness and the ability to concentrate, significantly benefiting those with ADHD.
  3. Appetite Suppression: By affecting the brain's dopamine system, Adderall can decrease feelings of hunger, making individuals feel fuller, which might inadvertently support weight management.

The medication is available in both immediate and extended-release forms, catering to different needs and lasting for varying durations. This flexibility allows for tailored treatment plans that match the specific requirements of each patient, ensuring sustained focus and attention control throughout the day.

The difference between Phentermine and Adderall

Phentermine vs Adderall: What’s the difference?

Phentermine and Adderall are both central nervous system stimulants, but they are prescribed for very different reasons and have distinct mechanisms of action and side effects. Here's a detailed comparison to understand their key differences:

Primary Use and FDA Approval

Phentermine is primarily prescribed as an appetite suppressant for weight loss in obese patients, and it's FDA-approved for this purpose. It is recommended for short-term use, typically up to 12 weeks, in conjunction with lifestyle modifications like diet and exercise. On the other hand, Adderall is approved for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy. It enhances focus, attention, and alertness but is not FDA-approved for weight loss.

Mechanism of Action

The mechanism of action also varies significantly between the two. Phentermine works by releasing neurotransmitters which suppress appetite and increase energy levels, primarily affecting norepinephrine and dopamine. Adderall, containing a combination of amphetamine and dextroamphetamine, increases the release of these neurotransmitters in the brain but with a focus on enhancing alertness and performance, making it effective for ADHD.

Potential for Abuse and Dependency

Adderall is classified as a Schedule II controlled substance, indicating a higher potential for abuse and dependency. This classification necessitates strict regulations on prescribing and dispensing. Phentermine, while still a controlled substance, is categorized under Schedule IV, which is associated with a lower risk of abuse compared to Schedule II drugs.

Understanding these differences is crucial for choosing the right medication based on individual health needs and conditions. Always consult with a healthcare provider to determine the most appropriate treatment option.

Effectiveness for Weight Loss

Phentermine is FDA-approved specifically for weight loss when combined with diet and exercise, making it a viable treatment for significant overweight. Clinical studies have shown that adults with obesity who took phentermine experienced up to 9% more weight loss than those who took a placebo medication. This highlights phentermine as a more appropriate choice for those seeking weight loss assistance, as it is designed for this purpose.

In contrast, Adderall is not approved for weight loss and should not be used off-label for this purpose. While it can cause decreased appetite and weight loss, these effects are often accompanied by serious side effects such as high blood pressure, increased heart rate, and potential for abuse and dependence. Long-term use of Adderall for weight loss can lead to a rebound effect, where weight or body mass index returns to pre-prescription levels once the drug is discontinued, making it a less sustainable option.

Furthermore, weight loss with Adderall is generally modest and usually isn't enough to significantly reduce or sustain extreme weight loss. The potential for misuse and the serious health risks associated with its use for weight loss underscore the importance of choosing medications that are specifically intended and approved for this purpose, like phentermine. Long-term success with weight loss often requires sustainable lifestyle changes rather than relying solely on medication.

Which is better: Phentermine or adderall

When considering the effectiveness of Phentermine and Adderall for weight loss, it's essential to focus on the intended use and approval status of each medication. Phentermine is explicitly FDA-approved as a weight loss aid, making it a more suitable and reliable option for those specifically looking to manage significant overweight issues. This approval is based on extensive clinical trials and research that confirm its efficacy and safety for weight loss when used as directed.

Comparative Analysis: Phentermine vs. Adderall for Weight Loss

  1. FDA Approval and Intended Use:
  2. PhentermineApproved specifically for weight loss.Adderall: Not approved for weight loss; primarily prescribed for ADHD and narcolepsy.

Given the specific approval and recommendation for weight loss, Phentermine stands out as the better choice for those whose primary goal is reducing weight. It is designed to be part of a comprehensive weight management program that includes dietary changes and physical activity, which aligns with health professionals' recommendations for sustainable weight loss.

Dosage Comparison: Phentermine Vs adderall

Phentermine and Adderall are available in various dosages and forms, tailored to meet different therapeutic needs. Here's a detailed look at their dosage forms:

  1. Phentermine:
  2. Capsules: Available in 15 mg, 30 mg, and 37.5 mg.Tablets: Offered in 8 mg and 37.5 mg.Typically, Phentermine is prescribed once a day in the morning if using extended-release capsules or half an hour before meals if using tablets, three times a day.
  3. Adderall:
  4. Immediate-release (IR) Tablets: Available in 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 20 mg, and 30 mg.Extended-release (XR) Capsules: Available in 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, and 30 mg.

Dosage Adjustments and Monitoring

The approach to dosing for Phentermine and Adderall involves careful consideration and monitoring by healthcare providers:

  • Phentermine: The dosage is usually started low and increased gradually over time to assess the body's response and effectiveness in weight loss. Your doctor will monitor your progress and adjust the dosage accordingly.
  • Adderall: Dosage adjustments are also common with Adderall, particularly due to its potential for dependency and the need to manage symptoms of ADHD effectively.

Administration Guidance

Your healthcare provider will advise on the best way to take these medications based on your specific health needs:

  • Phentermine: It is generally recommended to take Phentermine once a day in the morning, especially if using extended-release capsules, to maximize its appetite-suppressing effects throughout the day.
  • Adderall: The administration of Adderall can vary depending on whether you are using immediate-release tablets or extended-release capsules, with the former often taken multiple times a day and the latter typically once daily.

These guidelines ensure that both medications are used safely and effectively, minimizing potential side effects while maximizing therapeutic benefits. Always follow your healthcare provider's instructions and discuss any concerns about your medication regimen.

Phentermine and adderall drug interactions

Phentermine and Adderall, both central nervous system stimulants, have significant interactions with other medications and certain health conditions. It is crucial to understand these interactions to avoid serious health risks.

Key Drug Interactions and Health Considerations

  1. Contraindications: Both medications should not be used by individuals with a history of heart disease, overactive thyroid, glaucoma, or substance use disorder, and those who are pregnant or nursing.They are also contraindicated in patients currently taking monoamine oxidase inhibitors (MAOIs) due to severe interaction risks.
  2. Interaction with Other Medications: Phentermine interacts with 194 drugs, including antacids and vitamin C, with 43 of these interactions classified as major.Adderall interacts with 201 drugs, including significant interactions with MAOIs, SSRIs, SNRIs, and several cardiovascular medications.
  3. Substance Interactions: Both drugs interact moderately with alcohol, which can increase the risk of cardiovascular side effects.Adderall has additional interactions with substances like caffeine and methamphetamine, which can exacerbate side effects.

Risk of Combined Use

  • Combining Phentermine and Adderall is highly discouraged due to the increased risk of severe side effects such as high blood pressure, nausea, and cardiovascular issues.
  • Both drugs can cause hypertension, seizures, or serotonin syndrome when taken with conflicting medications.

Recommendations for Safe Administration

  • If transitioning from Phentermine to Adderall, it is advisable to allow a clearance period of about five days for Phentermine to leave the system completely before initiating Adderall.
  • Always consult with a healthcare provider before starting, stopping, or combining these medications to ensure safety and efficacy.

This information underscores the importance of careful medication management and adherence to medical advice when dealing with potent prescription drugs like Phentermine and Adderall.

Side Effects and Safety Concerns

Phentermine and Adderall, both potent stimulants prescribed for specific health conditions, carry a range of side effects that can impact your health. Understanding these side effects is crucial for safely managing your medication regimen.

Common Side Effects

  1. Phentermine: Increased heart rate and blood pressureDry mouth, unpleasant tasteSleeplessness, nervousness, constipationTingling or prickling feeling in hands or feet
  2. Adderall: Insomnia, disrupted sleep patternsLoss of appetite, weight lossMood swings, anxiety, stomach painIncreased heart rate and blood pressure

Serious Side Effects

  • Phentermine may lead to severe cardiovascular issues like palpitations, shortness of breath, and angina, as well as swollen legs and ankles.
  • Adderall has been noted to cause psychological reactions such as depression and mania, alongside physical effects like slowed speech, numbness, seizures, and even cardiovascular problems.

Safety Concerns and Recommendations

Both medications should be avoided by individuals with pre-existing conditions such as heart disease, hypertension, glaucoma, or a history of substance use disorders. They are also not recommended for pregnant or breastfeeding women due to the risk of serious side effects or birth defects. Regular consultation with a healthcare provider is essential to monitor for adverse effects and manage the dosage appropriately to mitigate risks.

Understanding Controlled Substance Scheduling and Prescription Regulations

Phentermine and Adderall are both controlled substances regulated under the Controlled Substances Act (CSA), which classifies drugs based on their potential for abuse and dependence. Phentermine is categorized as a is , indicating a lower potential for abuse, primarily prescribed for weight loss. Conversely, Adderall falls under Schedule II, highlighting a higher risk of abuse and is used mainly for treating ADHD and narcolepsy.

Prescription Requirements and Healthcare Provider Guidelines

Prescriptions for these medications must be issued by licensed healthcare providers, including physicians, nurse practitioners, or physician assistants. The specific rules around prescribing can vary by state, and in some cases, mid-level practitioners may face additional requirements such as needing a collaborative agreement with a physician. Always consult with a healthcare professional before starting any new prescription to ensure compliance with local laws and medical guidelines.

Compliance with DEA Regulations

The Drug Enforcement Administration (DEA) oversees the prescription of controlled substances, enforcing strict guidelines on how these drugs can be prescribed and dispensed. This includes ensuring that healthcare providers are up-to-date with the latest regulations to avoid legal issues and ensure patient safety. Given the serious side effects and potential for addiction associated with both Phentermine and Adderall, it is crucial to use these medications under close supervision and adhere strictly to prescribed guidelines.

Financial Considerations

A man taking weight loss medication

When considering Phentermine and Adderall for weight management or ADHD treatment, it's essential to understand their cost implications, especially since these medications may be used over extended periods. Here's a breakdown of the financial aspects of both drugs:

Monthly Supply Cost Analysis

The average retail price for a month's supply of Phentermine is approximately $20-$30 for the generic version, while the brand name version, Adipex-P, can reach up to $100. Conversely, a month's supply of Adderall costs around $150-$200 for the generic version, with the brand name version potentially costing up to $300. These costs can fluctuate based on the pharmacy and the specifics of one's insurance plan.

Savings Options

To mitigate some of these expenses, consider using discount programs like GoodRx or exploring patient assistance programs. These options can significantly reduce out-of-pocket costs, making long-term treatment more accessible. Always consult with your healthcare provider to ensure you are obtaining your medications in the most cost-effective manner while adhering to your prescribed treatment plan.

Key Takeaways

Key Takeaways

  1. Potential for Abuse and Dependency: Both Phentermine and Adderall share a significant potential for abuse and dependency, attributed to their properties as stimulants. This characteristic necessitates careful monitoring and regulation by healthcare providers to prevent misuse and manage treatment effectively.
  2. Mechanism of Action: The effectiveness of both Phentermine and Adderall in enhancing mental alertness and reducing fatigue is rooted in their ability to release neurotransmitters like dopamine and serotonin. This action not only suppresses appetite but also improves mood, which can be beneficial in the management of conditions they are prescribed for.

Conclusion and Recommendations

The exploration of Phentermine versus Adderall in the context of weight loss and medical treatment presents a nuanced understanding of their applications, regulatory status, and health implications. This discussion highlights Phentermine as a viable option specifically approved for weight loss, distinguishing it from Adderall, which, while effective in enhancing focus and attention in ADHD and narcolepsy patients, is not sanctioned for weight management purposes. The careful consideration of each medication's side effects, potential for abuse, and interaction with other drugs underscores the importance of informed consultation with healthcare providers.

Moving forward, it's imperative for individuals considering these medications to weigh their options in collaboration with medical professionals, prioritizing safety and efficacy. The emphasis on Phentermine for those seeking weight loss, paired with lifestyle modifications, and Adderall's role in managing ADHD, showcases the targeted approach needed in choosing the right medication for one's health objectives. As research continues to evolve and our understanding of these drugs deepens, the conversation surrounding their use will undoubtedly expand, fostering informed decisions in the pursuit of health and wellness.


What distinguishes phentermine from Adderall?

Phentermine and Adderall are both medications that can have overlapping uses. Phentermine is primarily prescribed for weight loss and may also be used off-label to manage ADHD. Adderall is typically used to treat ADHD but can sometimes be prescribed for weight loss under specific circumstances. The two medications differ in their dosing requirements, age restrictions for certain uses, and the side effects they may cause.

How does phentermine aid in weight loss?

Phentermine assists in weight loss primarily by reducing hunger or helping individuals feel fuller for longer periods. Additionally, phentermine is available in a combination with topiramate under the brand name Qsymia, which is approved for long-term weight loss management.

Is it safe to use phentermine and Adderall together?

Currently, there are no known interactions between phentermine and Adderall, suggesting that they can be used together. However, it's important to consult a healthcare provider before starting or combining these medications to discuss potential risks and benefits.

Which weight loss pill is the most effective?

The most effective weight loss medications currently available are GLP-1 agonists. These include liraglutide (Saxenda), semaglutide (Wegovy), and tirzepatide (Zepbound), all of which are approved for weight loss. Some other GLP-1 agonists might also be prescribed off-label for this purpose. These drugs are considered safe for long-term use in managing obesity.

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