From the Guidelines
The recommended dose of Adipex (phentermine) for weight loss is 15 mg daily, which can also be administered as 1/4 or 1/2 pill, as indicated in the study published in Clinical Gastroenterology and Hepatology 1. When considering Adipex for weight loss, it is essential to note that the medication should be used as part of a comprehensive weight management program that includes diet and exercise. The study suggests that pharmacotherapy, including Adipex, should be considered as an adjunct to lifestyle changes in patients who have been unable to lose and maintain weight with diet and exercise alone 1. Some key points to consider when prescribing Adipex include:
- The medication is a Schedule IV controlled substance and has potential for dependence
- Common side effects include dizziness, dry mouth, difficulty sleeping, irritability, nausea/vomiting, diarrhea, and constipation
- Adipex is contraindicated in patients with pregnancy, nursing, cardiovascular disease, during or within 14 days of MAOIs, other sympathomimetic amines, hyperthyroidism, glaucoma, agitated states, history of drug abuse, or concomitant alcohol use
- The medication should be initiated with dose escalation based on efficacy and tolerability to the recommended dose, with assessment of efficacy and safety at least monthly for the first 3 months and then at least every 3 months 1. It is crucial to weigh the potential benefits of Adipex against the potential risks and to closely monitor patients for any adverse effects, particularly given the potential for dependence and the contraindications listed in the study 1.
From the FDA Drug Label
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. Dosage should be individualized to obtain an adequate response with the lowest effective dose.
The dose of Adipex (phentermine) for weight loss is 15 mg to 30 mg daily, taken at approximately 2 hours after breakfast for appetite control 2. The dosage should be individualized to obtain an adequate response with the lowest effective dose. A daily dose of 30 mg has been found to be adequate for appetite control for 12 to 14 hours 2.
- The recommended dose is 15 mg to 30 mg daily.
- The dose should be taken at approximately 2 hours after breakfast.
- Individualization of the dose is necessary to obtain an adequate response with the lowest effective dose.
- A daily dose of 30 mg is adequate for appetite control for 12 to 14 hours 2.
From the Research
Adipex Dosage for Weight Loss
The dosage of Adipex, also known as phentermine, for weight loss is not explicitly stated in the provided studies. However, some studies mention the dosage of phentermine in combination with other medications.
- Phentermine/topiramate is mentioned in several studies as an approved medication for weight loss therapy in the USA 3, 4, 5.
- The study published in 2021 mentions that phentermine/topiramate has a placebo-subtracted weight reduction of 6.8% 4.
- Another study published in 2016 mentions that phentermine-topiramate is associated with a significant excess weight loss of 8.8 kg compared to placebo at 1 year 5.
- The study published in 2025 mentions that phentermine is one of the seven FDA-approved anti-obesity medications, but it does not provide specific dosage information 6.
- The study published in 2022 mentions that phentermine is an older medication approved for chronic weight management, but it does not provide specific dosage information 7.
Key Points
- Phentermine is an approved medication for weight loss therapy in the USA.
- Phentermine/topiramate is associated with significant weight loss compared to placebo.
- The exact dosage of Adipex (phentermine) for weight loss is not explicitly stated in the provided studies.
- Phentermine is one of the seven FDA-approved anti-obesity medications, but specific dosage information is not available in the provided studies.