The progestin drugs of implants and injections are not progesterone and so can cause side effects such as depression.
They also cause irregular “breakthrough bleeds” which are not real periods.
What’s the difference between a real period, a pill-bleed, and the breakthrough bleed of a contraceptive implant or injection?
The bleeds on birth control are not real periods
A real period is a withdrawal bleed from the body’s own progesterone. It occurs at the end of an “ovulatory” menstrual cycle, which is a menstrual cycle in which ovulation occurred and progesterone was made. The timing of a real period is about the healthy functioning of the ovaries.
👉🏽Tip: Ovulation is the main event of a menstrual cycle.
A pill-bleed is a withdrawal bleed from the contraceptive drugs ethinylestradiol and a progestin. The timing of pill-bleed is about the dosing of those drugs. There is not (and never was) any reason to bleed monthly on hormonal birth control. Watch the short animation Why hormonal birth control can never regulate periods.
A breakthrough bleed is the bleed that happens when the uterine lining has been exposed to estrogen, but not progesterone. It’s an anovulatory bleed that occurs with progestin-only methods of birth control, as well as perimenopause and PCOS.
👉🏽Tip: The bleeds on a hormonal IUD can be real “ovulatory” menstrual cycles. Read The pros and cons of the hormonal IUD.
The progestins used in implants and injections
Progesterone is a beneficial hormone for mood, hair, thyroid, bones, skin, and immune function. Unfortunately, there’s no progesterone in any type of hormonal birth control. Instead, contraceptive injections and implants contain the progestin steroid drugs medroxyprogesterone acetate, levonorgestrel, or etonogestrel, many of which have a high androgen index and so cause weight gain.
Medroxyprogesterone acetate is the progestin in the Depo-Provera injection. It suppresses ovarian function so severely that it causes bone loss due to estrogen deficiency. Medroxyprogesterone acetate can also cause insulin resistance and unstoppable weight gain.
Levonorgestrel is the progestin in the implants Norplant and Jadelle. It’s derived from testosterone and so can cause androgenic (male hormone) side effects such as acne, hair loss, and weight gain. Levonorgestrel and other progestins can cause ovarian cysts and have also been linked with anxiety and depression.
Etonogestrel is the progestin in the implants Nexplanon or Implanon. Like levonorgestrel, etonogestrel can cause ovarian cysts and mood problems, but it’s less androgenic (testosterone-like) so is less likely to cause acne, hair loss, and weight gain.
Ask me in the comments.