8 mg

Doses per day:   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:  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:  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:  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.

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.