If you learn one thing from this blog, let it be this: The progestins in hormonal birth control are not progesterone.
It seems simple, and it should be simple. Yet most journalists, doctors, and even the British Medical Journal get it wrong. They use the word progesterone when they really mean a progestin such as drospirenone, levonorgestrel, or medroxyprogesterone. They’re not the same thing. At all.
It’s an understandable mistake. After all, estrogen is a generic term. It can be used to refer to anything estrogenic such as estradiol, ethinylestradiol in the Pill, and xenoestrogens from the environment.
Progesterone is not a generic term. It’s one thing. It’s progesterone, and there is no other.
The many progestins used in hormonal birth control and hormone replacement are something different. Just how different? Take a look below at the molecular structures of progesterone and levonorgestrel (the progestin used many oral contraceptives, implants, Mirena IUD, and the morning-after pill).
Can you spot the difference?
Levonorgestrel is actually more similar to testosterone than it is to progesterone (which is why levonorgestrel causes hair loss).
No wonder progesterone and progestins have such vastly different physiologic effects!
How to get more progesterone
Progesterone is beneficial for mood and hair. It boosts thyroid hormone and promotes sleep.
You might be thinking you’d like to take some progesterone, but please remember:
There’s no progesterone in hormonal birth control. There’s no progesterone in conventional hormone replacement (HRT). Those are progestins.
There are only two ways to get real, natural progesterone:
- Make it yourself. For details, please see Roadmap to Progesterone and my book Period Repair Manual.
- Take bioidentical progesterone. Bioidentical means human-identical. It’s made in the lab from yam sterols (like all hormone replacement), but it’s made to be actual progesterone—not drospirenone or another progestin. Bioidentical progesterone’s molecular structure looks like progesterone in the diagram above. You can detect it on a blood test for progesterone (try detecting drospirenone on a blood test!). Bioidentical progesterone is the progesterone used in fertility treatment. It’s also available as Prometrium capsules, natural progesterone cream, or compounded hormone replacement. Bioidentical progesterone cannot be used as birth control.
I hope this clears up some confusion about progesterone and progestins.