What is the dose of Adipex (phentermine)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: February 19, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

The recommended dose of Adipex, also known as phentermine, is 15-37.5 mg once daily.

Key Considerations

  • The typical starting dose is 15-18.75 mg per day, and the dose may be adjusted based on individual response and tolerance 1.
  • The maximum recommended dose is 37.5 mg per day.
  • Phentermine should be taken preferably earlier in the day to minimize risk of insomnia 1.
  • A low-dose formulation of phentermine, 8 mg, is also available and can be taken up to 3 times per day, approximately 30 minutes before meals 1.

Important Safety Information

  • Phentermine should be used for a short period of time, typically 3 months or less, and under the guidance of a healthcare professional 1.
  • It is essential to follow the prescribed dosage and not exceed the recommended dose to minimize the risk of adverse effects, such as constipation, dry mouth, palpitations, insomnia, and irritability 1.
  • Phentermine should be avoided in patients with a history of cardiovascular disease or uncontrolled hypertension, as well as those treated with, or within 14 days of, monoamine oxidase inhibitors 1.

From the FDA Drug Label

  1. 1 Exogenous Obesity Dosage should be individualized to obtain an adequate response with the lowest effective dose. The usual adult dose is 15 mg to 30 mg at approximately 2 hours after breakfast for appetite control. Administration of one capsule (30 mg) daily has been found to be adequate in depression of the appetite for 12 to 14 hours.

The dose of Adipex (phentermine) is 15 mg to 30 mg daily, administered at approximately 2 hours after breakfast for appetite control 2.

  • The recommended dose is individualized to obtain an adequate response with the lowest effective dose.
  • A dose of 30 mg daily has been found to be adequate in depressing appetite for 12 to 14 hours.

From the Research

Dose of Adipex (Phentermine)

The dose of Adipex, also known as phentermine, varies depending on the specific formulation and the patient's response to treatment.

  • In the study 3, two doses of phentermine were used: 7.5 mg and 15.0 mg, both in combination with topiramate.
  • Another study 4 analyzed the efficacy of 30 mg phentermine and found that weight loss at the first month and development of tolerance could be useful predictors of 6-month efficacy.
  • The exact dose of phentermine used in the study 5 is not specified, but it is mentioned that phentermine monotherapy was used in pediatric patients with a mean treatment duration of 10 months.
  • It is worth noting that the combination of phentermine and topiramate has been studied in several trials, with doses of phentermine ranging from 7.5 mg to 15.0 mg per day 3, 6, 7.

Common Doses of Phentermine

Some common doses of phentermine include:

  • 7.5 mg per day, often used in combination with topiramate 3, 6
  • 15.0 mg per day, also used in combination with topiramate 3, 6
  • 30 mg per day, used as a single agent in some studies 4

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.