Write the next sentence in this paragraph:

How to balance hormones for acne
Use oral contraceptives.
If acne is thought to be complicated by a hormonal imbalance, your dermatologist may choose hormone replacement therapy (hrt) as part of the treatment. The most common hrt for acne is contraceptive therapy using birth control pills.
These often contain estrogens, progestins or both in varying concentrations. The type and dosing of oral contraceptive is an important factor in acne treatment, and only a dermatologist specialized in their usage for this condition should be treating acne with hrt.