A dosage of 10 µg/day EE has been found to increase CBG levels by 50%, while a dosage of 20 µg/day EE increased them by 100%. Progestins that are progesterone derivatives have no effect on CBG levels, while androgenic progestins like the 19-nortestosterone derivatives have only a weak effect on CBG levels. COCs may increase CBG levels by 100 to 150%. A dosage of 5 µg/day EE has been found to increase TBG levels by 40%, while a dosage of 20 µg/day EE increased them by 60%. Progestins that are progesterone derivatives do not affect TBG levels, while progestins with androgenic activity may decrease TBG levels. A combination of 30 µg/day EE and 1 mg/day norethisterone, a moderately androgenic progestin, have been found to increase TBG levels by 50 to 70%, while the combination of 30 µg/day EE and 150 µg/day desogestrel increased them by 100%.