Vitamin D and Hormones
In Alberta, we spend nearly half the year under skies that do not provide enough UVB light for reliable vitamin D production. Vitamin D is critical for overall health including hormone balance reproduction, ovarian health, mood, and immune balance.
For many women, low vitamin D contributes to irregular cycles, fatigue, low mood, PMS, poor sleep, and hormone imbalance.
Vitamin D Is Actually More Like a Hormone
Vitamin D behaves more like a steroid hormone than a traditional vitamin. Once sunlight hits the skin, the body converts a cholesterol compound into vitamin D3, which is then activated in the liver and kidneys.
Vitamin D receptors are found throughout the reproductive system, including the ovaries, uterus, placenta, and pituitary gland. Researchers continue to explore how vitamin D influences:
Estrogen and progesterone balance
Ovulation
Egg quality
Insulin sensitivity
Inflammation
Immune regulation
Mood and neurotransmitters
Endometrial receptivity and implantation
Low vitamin D levels are also commonly seen alongside PCOS, endometriosis, and autoimmune conditions, as well as unexplained infertility.
Vitamin D and Fertility
Healthy vitamin D levels appear to support reproductive health in both women and men. Studies suggest vitamin D may help regulate ovarian follicle development, implantation, and hormone signaling.
For women trying to conceive, adequate vitamin D may support:
More regular ovulation
Improved egg maturation
Better endometrial receptivity
Reduced inflammation
Healthier insulin response
In men, vitamin D may also influence testosterone production and sperm motility.
Many fertility practitioners now routinely test vitamin D levels because deficiency is so common in northern climates like Alberta.
Vitamin D and Perimenopause
Perimenopause is a time of fluctuating estrogen and progesterone levels, often accompanied by fatigue, anxiety, sleep disruption, joint pain, mood changes, and brain fog.
Interestingly, many symptoms of vitamin D deficiency overlap with perimenopausal symptoms:
Low mood
Fatigue
Muscle aches
Poor sleep
Reduced resilience to stress
Hair shedding
Low immunity
Vitamin D also helps regulate calcium metabolism, which becomes increasingly important as estrogen declines and bone density naturally decreases.
Many women entering perimenopause discover they are significantly deficient — especially after years of indoor work, sunscreen use, and long Alberta winters.
The Skin: Our Natural Vitamin D Factory
The skin is where vitamin D production begins.
When UVB rays from sunlight hit the skin, they interact with a cholesterol compound called 7-dehydrocholesterol, triggering the formation of vitamin D3.
This process depends on several factors:
Latitude
Season
Time of day
Skin pigmentation
Age
Amount of exposed skin
Sunscreen use
Calgary is far enough north that the angle of the sun is to low for sufficient UVB exposure during much of the year, roughly October to April. So even our bright, sunny winter sky’s won’t help our bodies produce vitamin D.
What About the Eyes?
This is where things become especially interesting.
The eyes themselves do not produce vitamin D, but light entering the eyes strongly influences circadian rhythm, hormone signaling, cortisol regulation, melatonin production, and reproductive hormones.
Morning outdoor light exposure helps regulate the brain’s master clock through the retina and hypothalamus. This affects:
Sleep quality
Cortisol rhythm
Melatonin
Mood
Reproductive hormone timing
Natural daylight exposure through the eyes may indirectly support hormonal balance, even when UVB levels are too low for vitamin D production.
In other words:
Skin exposure helps produce vitamin D.
Light entering the eyes helps regulate hormonal rhythms and circadian health.
How to Get Vitamin D Naturally in Alberta
Because Alberta sits at a northern latitude, timing matters far more than most people realize.
1. Midday Sun Is Best
Vitamin D production depends on UVB rays, which are strongest when the sun is high in the sky — generally between 10 a.m. and 3 p.m.
Morning and evening sunlight may feel warm, but they contain very little UVB for vitamin D production.
2. Expose More Than Just Your Face
The body makes far more vitamin D when larger skin surfaces are exposed. Arms and legs are ideal when weather permits. I actually like to have less exposure on my face and focus on arms and legs.
3. Short, Consistent Exposure Works Better
For many light-skinned individuals, short exposures of roughly 5–20 minutes during summer months may be sufficient before sunscreen or long layers are applied. Those with darker skin tones may require significantly longer exposure.
The goal is never burning.
4. Winter Sun Often Isn’t Enough
From late fall through early spring in Alberta, UVB intensity is usually too weak for significant vitamin D synthesis, regardless of outdoor time.
This is why many Albertans require:
Fatty fish
Egg yolks
Fortified foods
Or supplementation during winter months
Signs You Might Be Low in Vitamin D
Common signs can include:
Fatigue
Frequent illness
Low mood
PMS
Fertility struggles
Muscle aches
Poor recovery
Hair shedding
Low libido
Sleep disruption
Bone or joint discomfort
Because these symptoms overlap with stress, thyroid imbalance, and perimenopause, deficiency often goes unnoticed.
Final Thoughts
Vitamin D sits at the intersection of, hormone balance, metabolism, fertility, immune health, and mood. In Alberta’s northern climate, deficiency is incredibly common — especially during winter and early spring.
The body was designed to interact with natural light through both the skin and the eyes. Safe sun exposure, outdoor movement, morning light for circadian rhythm support, nutrient-dense foods, and appropriate supplementation can all help support hormonal health. This is important during fertility journeys and the transition through perimenopause.
For many women, optimizing vitamin D may be one of the simplest foundational steps toward better energy, healthier cycles, improved resilience, and overall hormonal balance