Triphasic oral contraceptives may vary both the estrogen and progestin levels at different times during the cycle.
The goal of the biphasic and triphasic formulations is to achieve adequate control of the menstrual cycle while using lower doses of both estrogens and progestins, thereby reducing the risk of adverse effects.
There are three main types of pill packs and hormone combinations – monophasic, biphasic, and triphasic.
Biphasic has a 21-day pill pack featuring two different amounts of hormone combinations throughout the three-week cycle, and triphasic has a 21-day pill pack with three different hormone dosage amounts throughout the three-week cycle.
Combination pills are available in monophasic, biphasic, and triphasic.