Hello  Pinterest logo  Friend,

Welcome to!

The official website of the #1 diet pill in the USA

Want to Buy Phentermine Online?

Since 2008, it is not possible to buy phentermine online without a prescription. If you are interested in a prescription for this weight loss medication, make an appointment with your doctor or a local weight loss clinic to discuss your options.

Read all about it in our extensive guide on How to Buy Phentermine Online.

Don't want to spend precious time, effort and money finding a local doctor that prescribes phentermine? Try Phen Caps - an effective, OTC alternative! Trusted by over 30,000 customers!

5 Things To Know About Phentermine

Phentermine HCL

  1. How it works
    Phentermine causes the brain to stimulate the adrenal glands to release norepinephrine, a neurotransmitter which signals a fight-or-flight response, reducing hunger.
  2. Prescriptions
    As phentermine has a pharmacology similar to amphetamine, it is classified as a controlled substance and is therefore only available on prescription.
  3. Combinations
    The two most commonly encountered phentermine combinations are Phen-Pro, which is a combination of phentermine and a low dose of an anti-depressant such as Prozac, and Qsymia, a combination of phentermine and topiramate, an anticonvulsant with weight loss side effects.
  4. Withdrawal Symptoms
    The most common withdrawal symptoms are fatigue, weight gain, insomnia, and low mood.
  5. The Phentermine Alternative
    For those people who do not have a phentermine prescription, or similarly, for those who have tried phentermine and found the side effects to be intolerable, Phen Caps offer a great solution.

Learn more >>


Common Phentermine Doses

8 mg

Doses per day:  Pill icon x3

8mg is the lowest dose of phentermine currently available. It can be taken up to three times per day. 

This dose is especially intended for patients that struggle with nighttime snacking, or those who are highly sensitive to the effects of phentermine.

15 mg

Doses per day: Pill icon x1/x2

This a lower dose of phentermine that can be taken either once or twice per day. Multiple companies produce 15mg capsules. 

Since the goal is to find the lowest effective dosage, doctors may start patients on 15mg and then increase dosage if needed.


18.7 mg

Doses per day: Pill icon x1/x2

People most often find themselves taking 18.5mg when they split a 37.5mg tablet in half.

Some doctors recommend this dosage at the start or end of phentermine treatment. It is also taken as a twice-per-day dosage to spread out the medication.


37.5 mg

Doses per day: Pill icon x1

This is the maximum dose of phentermine. The most popular US brand. Adipex is sold in 37.5mg pills.

This dose is only taken once per day, consider speaking with your doctor about stopping phentermine if this dose is no longer effective.


Side Effects

The most commonly reported side effects of phentermine are:

Dry mouth











Over 18 years old

Phentermine is only suitable for those over 18 years old.


Pregnant woman

It should not be taken by anyone who is pregnant, expecting to become pregnant, or breastfeeding.


Health issues history

You should not take phentermine if you have a history of heart disease, uncontrolled blood pressure, overactive thyroid, glaucoma, a history of pulmonary hypertension, or if you have a history of drug or alcohol abuse.



Phen Caps give similar benefits as phentermine, such as supressing appetite, stimulating your metabolism and increasing energy, without the side effects. Phen Caps do not contain phentermine, making them available without a prescription to anyone.

Learn more >>