06/18/2026
Did you know…..
Thyroids are nuanced? Every person has specific and varied needs based on current labs and lifestyle.
If you have been told your thyroid is fine, but you still feel like you are running on a low battery, listen up.
Most people know that the thyroid produces a hormone called T4.
What fewer people know is that T4 is essentially INactive.
It is a storage hormone.
For it to actually work in your body, it needs to be converted into the active form, T3 (free), and that conversion is where so many people struggle.
Your T4 labs may look fine and that’s likely what your physician has, sadly, only ordered.
You need the full picture. A full thyroid panel. You don’t even need to go to the physician in order to request labs. Order for yourself right here for a fraction of the cost: https://ultalabtests.com/partners/crazygoodco
(Type Crazy Good Thyroid in the search box and Viola, all set!). You’ll schedule your own appointment online, go to your blood draw, get full results back in a few days via email & download the pdf to share with your practitioner.
Lots of nutrients are required to feed the conversion.  Things like selenium and iodine. Plus, your liver needs to be able to process T4 into T3 hormones effectively. Your liver works really hard to filter and process all day long.
Your body needs Free T3 flowing to feel energetic. To have warm hands and feet. To have proper digestion. To grow hair, skin and nails. Your thyroid is the master regulator for all things metabolism.
There is a step that is rarely discussed in the Thyroid Pathway conversion - that I think you might be interested to learn about……. And one of the most important players in that conversion process is a hormone that is barely mentioned in the same breath as thyroid health: Progesterone.
What Progesterone Does for Your Thyroid
Progesterone supports the conversion of inactive T4 into active T3 in a bunch of ways:
🦋 It directly stimulates the enzyme (5-deiodinase) responsible for removing an iodine molecule from T4 to create T3.
🦋 It opposes estrogen, which, when in excess, actively suppresses thyroid conversion.
🦋 It supports thyroid receptor sensitivity, meaning your cells can actually respond to the thyroid hormone that does arrive.
🦋 It has a warming, calming effect on metabolism that works in concert with thyroid hormone.
When progesterone is low, conversion suffers. Less active T3 reaches your cells and you feel it: fatigue, weight gain, low mood, poor sleep, hair thinning, cold hands and feet, and that frustrating flatness that no amount of rest seems to fix.
When Does Progesterone Drop?
Progesterone begins declining around age 35 and drops significantly through peri-menopause.
By the time many women reach menopause, it is barely detectable. This is one of the key reasons thyroid symptoms so often emerge or worsen in midlife, even in women who have never had a thyroid concern in the past.
Other factors that deplete progesterone:
🦋 Chronic stress (cortisol production competes directly with progesterone in what is known as the pregnenolone steal)
🦋 Estrogen dominance
🦋 Nutritional deficiencies, particularly zinc, vitamin B6, and vitamin C
🦋 Oral contraceptive use
Nutrients That Support Progesterone Production:
🦋 Vitamin B6
Essential for progesterone synthesis and for reducing the estrogen dominance that suppresses it.
Food sources: chicken, turkey, wild salmon, potatoes, bananas, and sunflower seeds.
Daily target: 1-1.7mg per day from food, higher therapeutic doses via supplementation under practitioner guidance.
🦋 Zinc
Supports the pituitary signal (luteinizing hormone, LH) that triggers progesterone production, after ovulation.
Food sources: oysters, red meat, pumpkin seeds, and eggs.
Daily target: 8-12mg per day.
🦋 Vitamin C
Concentrates in the corpus luteum (the structure that produces progesterone after ovulation) and directly supports progesterone output.
Food sources: kiwi fruit, citrus, strawberries, and broccoli.
Daily target: at least 500mg per day, higher under stress.
🦋 Magnesium
Supports the adrenal function needed for healthy hormone production and reduces the cortisol that competes with progesterone.
Food sources: dark leafy greens, pumpkin seeds, dark chocolate, and almonds.
Daily target: 300-420mg per day.
What About Progesterone Replacement?
For many women in perimenopause and menopause, optimizing nutrition is an important foundation but may not be enough. BioIdentical progesterone (as opposed to synthetic progestins) is being more recognized for its thyroid-supportive effects (plus its hormonal benefits). I often call progesterone on the Cinderella of hormones because she makes you calm, cool and collected. If you find yourself overly emotional or more easily angered than you used to be, odds are good that you could use some progesterone support.
This is a conversation worth having with a practitioner who understands both thyroid and hormone health together, rather than in isolation. And guess what? NOT every practitioner understands these nuances. It takes lots of additional training and time to learn about how the body is connected.
The Big Picture….
Thyroid health and hormonal health are not separate conversations. They are deeply intertwined. Progesterone does not just balance estrogen. It actively supports the conversion step that determines how much functional thyroid hormone your body produces each day.
If your T4 is adequate but your T3 is low or your symptoms persist despite treatment, low progesterone is one of the first places to investigate.
Cheers to being Crazy Good!!
So good, So healthy!
