Phentermine is a prescription weight loss medication that helps people lose weight by suppressing their appetite. One of the common questions asked by people who take phentermine is how long the effects of the how long does phentermine last in a day last in a day.

Phentermine has a half-life of about 25 hours, which means that it takes about 25 hours for half of the medication to be eliminated from the body. However, the effects of phentermine typically last for around 8-10 hours, depending on the individual's body chemistry and dosage.

To get the most benefit from phentermine, it's recommended to take the medication early in the day, preferably before breakfast. This is because phentermine can cause insomnia or other sleep disturbances when taken later in the day.

It's important to follow the dosage and administration instructions provided by your healthcare provider, and not to take phentermine for longer than recommended. Taking higher doses or taking the medication for longer than recommended can increase the risk of side effects and dependency.

If you're considering taking phentermine for weight loss, it's important to talk to your healthcare provider about whether the medication is appropriate for you, and to discuss any potential risks or side effects.