Too high an estrogen dose may cause breast tenderness or enlargement, weight gain, headache, or irritability. These side effects are far more common with non-bioidentical estrogens.
Progesterone taken by mouth often promotes sleepiness, so it should always be taken at night. Too high a dose may cause fatigue, nausea, or breast tenderness.
In women who have not had a hysterectomy, progesterone must always be given with estrogen, in order to avoid increasing the risk of uterine cancer. If sufficient progesterone is given, usually 50-100 mg daily, there will be no increased risk of uterine cancer. Progesterone blood level should be measured at least once after starting progesterone, about two hours after dosing, to verify that a satisfactory blood level is attained.
Vaginal bleeding may recur when estrogen and progesterone therapy are provided. This is usually brief and disappears within a few months. In women using hormone pellets, bleeding may be recurrent. It is generally of no significance. Lowering the dose of estrogen or raising the progesterone dose may be helpful. It may be reassuring to obtain an ultrasound study of the uterus to verify that excessive thickening has not occurred. As long as progesterone is also given, there is no increased risk of endometrial cancer.
Testosterone in women may cause acne, scalp hair loss, or facial hair growth. If these occur, the dose should be lowered. Higher testosterone dosage in the pellet may very substantially enhance libido.
Testosterone in men may uncover latent prostate cancer. The PSA should be measured after 3 months to verify no significant elevation. Testosterone may also raise blood count, and above a certain level this may promote increased blood clotting. The blood count should be checked 3 months after testosterone initiation to verify that the blood count has not gone too high.
Changes in medication, diet or weight may affect hormone levels, and may require dose adjustment.