What role does vitamin D play in progesterone therapy?
Vitamin D and progesterone are two of the most ancient and fundamental hormones in the human body — both derived from cholesterol, both essential to vertebrate life, and both dramatically deficient in modern populations.
Research published in 2009 confirmed that a lack of vitamin D reduces the benefits of progesterone. This means that if your vitamin D levels are low, progesterone therapy will be significantly less effective.
What they have in common:
The similarities between progesterone and vitamin D are remarkable. Both:
- Induce an anti-inflammatory response
- Suppress inflammatory cytokines (TNF-a, IL2, IL6)
- Support neurological function and prevent neurodegeneration
- Reduce damage from traumatic brain injury
- Regulate bone metabolism
- Are essential for a healthy pregnancy
- Inhibit abnormal cell growth (mitosis) and promote healthy cell differentiation
- Increase glutathione — the body's master antioxidant
- Positively affect skin and hair
Diseases linked to deficiency in both:
Low levels of both progesterone and vitamin D are found in asthma, depression, cancer, epilepsy, heart disease, migraines, PCOS, miscarriage, fibroids, autoimmune diseases (MS, lupus, arthritis), Alzheimer's disease, and seasonal affective disorder (SAD).
What levels should you aim for?
Most labs consider 30ng/ml (75nmol/L) adequate — but this is insufficient. Optimal blood levels are:
- 70–100ng/ml or 175–250nmol/L
The minimum recommended daily dose is 5,000IU, with latest research suggesting 10,000IU/day for optimal health.
Get tested:
A simple blood or home saliva test can confirm your vitamin D status. Home test kits are available through GrassrootsHealth and ZRT Laboratory.
For more detailed guidance visit our dedicated page on progesterone and vitamin D.