Phentermine is the most commonly prescribed prescription appetite suppressant, accounting for 50% of the prescriptions.

Phentermine first received approval from the Food and Drug Administration (FDA) in 1959 as an appetite suppressant for the short-term treatment of obesity.


Phentermine works by stimulating the hypothalamus gland and affecting certain neurotransmitters to decrease appetite. The hypothalamus is the region of the brain that controls the autonomic nervous system, regulating sleep cycles, body temperature, appetite, etc. Phentermine should NOT be used as a substitute for proper diet or exercise. For maximum effects, it must be used in conjunction with a reduced-calorie diet and/or exercise. Any modifications in your diet, activity level, and behavior must be developed and continued long-term in order to continue losing weight and prevent the lost weight from returning.


The length of your Phentermine treatment can be determined by Dr. Suarez. Depending on your current medical condition, Dr. Suarez can prescribe taking this for a few days to a few weeks. The length of treatment also determines as to how the person is reacting to the weight loss drug.

Usually, Dr. Suarez at Bella Medspa recommends three to six weeks of using Phentermine for obesity treatment. But, it can be taken safely up to 12 weeks. As much as possible, Dr. Suarez will make sure that the use of Phentermine is limited to a few weeks only. This is true because the longer a person uses Phentermine, the higher the chances of the individual can develop dependence to it.


There are other more common side effects, which may occur, but these do not usually require medical attention. They may be uncomfortable but should go away during treatment as your body adjusts to the medicine. However, if these side effects persist or become more problematic, you should contact your doctor for advice.
These are some of the most common phentermine side effects:

  • Change in sexual desire
  • Constipation
  • Diarrhea
  • Dizziness
  • Dry mouth (Xerostomia)
  • Headache
  • Insomnia
  • Mood changes
  • Nausea or vomiting
  • Rapid heartbeat
  • Stomach pain
  • Tiredness
  • Unpleasant taste