Phentermine for weight loss: how it works and what to expect
Phentermine is a prescription stimulant that suppresses appetite. Here's what the evidence shows about effectiveness, side effects, and who it's prescribed to.
Phentermine is a prescription appetite suppressant. It's a sympathomimetic amine, which means it works like adrenaline in your body. The medication stimulates your central nervous system to reduce hunger and increase energy.
How phentermine works
Phentermine triggers the release of noradrenaline in your brain. This activates your fight-or-flight response, which naturally decreases appetite. Most people feel less hungry within hours of taking it.
What it treats
Phentermine is prescribed for short-term weight management, typically for 12 weeks or less. Doctors prescribe it to people with a BMI of 30 or higher, or BMI of 27 with weight-related conditions like high blood pressure or diabetes.
Effectiveness
Studies show phentermine users lose about 3 to 5 pounds per week on average. Combined with diet and exercise, the average weight loss is around 10 pounds over 12 weeks.
Common side effects
Increased heart rate, elevated blood pressure, insomnia, dry mouth, and anxiety are reported frequently. These tend to fade as your body adjusts.
Who shouldn't take it
Phentermine isn't suitable if you have heart disease, uncontrolled high blood pressure, hyperthyroidism, or a history of substance misuse. It can also interact with certain medications, including some antidepressants.
Getting phentermine online
Many telehealth providers now offer phentermine consultations and prescriptions. A clinician will review your medical history and current medications before prescribing.