Running to get Vitamin D.

Is the vitamin D hormone just about bones? Not even close. In fact, it acts more like a hormone than a vitamin, with a hand in everything from mood to fertility. Here’s something interesting: despite all the health advice and supplements available, vitamin D deficiency is still surprisingly common even in sunny places. In the UK, a lack of sunlight makes this a widespread issue. 

But here's the thing: we live in Malaysia, bro. So hot, will we still lack vitamin D hormone? Hey, absolutely. Spending most of the day indoors, using sunscreen, or even having darker skin can affect how much vitamin D the body actually makes from sunlight.

What Is Vitamin D Really and Why Is It Called a Hormone?

Despite being called a vitamin, vitamin D is actually a type of hormone made by the body. It comes in two main forms: D2 and D3. The body makes D3 from sunlight hitting the skin, while some vitamin D can also come from food like fish, egg yolks, and fortified milk.

Here’s how it works, in simple terms:

  • Sunlight hits the skin.
  • The skin makes a raw form of vitamin D.
  • The liver and kidneys turn it into the active form the body can use.

What Are So Called ‘Vitamin D Hormone’?

Before diving into the details, here’s a quick list of key hormones that the vitamin D helps support:

  1. Parathyroid hormone (PTH) helps regulate calcium
  2. Estrogen and Progesterone supports reproductive health in women
  3. Testosterone and sperm-related hormones affects male fertility
  4. Serotonin and Dopamine impacts mood and brain function
  5. Insulin helps with blood sugar balance
  6. Thyroid hormones affects metabolism
  7. IGF-1 (Insulin-like Growth Factor 1) involved in growth and repair
  8. Adrenal steroid hormones relates to stress response
  9. SHBG (Sex Hormone-Binding Globulin) manages sex hormone activity

How Does Vitamin D Help With Calcium and Bone Health?

One of the best-known jobs of the vitamin D is helping the body absorb calcium. But it’s not just about getting more calcium, it’s about using it properly.

Here’s the hormone link:

  • When calcium is low, the parathyroid glands release PTH (Parathyroid Hormone).
  • Vitamin D function helps control how much PTH is released.
  • If there's not enough vitamin D, PTH goes up, which can lead to bone problems over time.

So it’s not just about drinking milk or eating cheese. Without good vitamin D function, calcium can’t do its job.

Does Vitamin D Affect Female Hormones?

Yes, it does. The vitamin D function is tied to the balance of estrogen and progesterone, the two main female reproductive hormones.

This means it can affect:

  • Menstrual cycles
  • PMS symptoms
  • Fertility
  • Menopause symptoms

Low vitamin D levels have even been linked to PCOS and irregular cycles. So, if hormones feel "off," it might not be just stress or age, it could be a sign of poor vitamin D function.

What About Male Hormones and Fertility?

The vitamin D isn’t just helpful for women. For men, it affects testosterone levels and sperm quality.

Good vitamin D levels may:

  • Boost sperm movement (motility)
  • Improve sperm shape
  • Support testosterone production

So yeah, vitamin D function matters for men too. It’s part of the picture when it comes to energy, sex drive, and fertility.

Can Vitamin D Really Improve Mood?

Ever notice feeling a little down during rainy seasons or when stuck indoors for too long? That might be your vitamin D talking.

This hormone helps the body produce serotonin and dopamine, the brain chemicals that make people feel good and stay motivated.

When vitamin D is low:

  • Mood may drop
  • Focus becomes harder
  • Sleep can feel off

Definitely. The vitamin D plays a role in how the body handles sugar through insulin, the hormone that controls blood sugar.

When vitamin D function is strong:

  • Insulin works better
  • Blood sugar stays stable
  • There are fewer energy crashes

What Does Vitamin D Do for the Thyroid?

The thyroid gland controls metabolism, energy, and more. But it also needs support to stay balanced.

Vitamin D function may reduce thyroid antibodies in conditions like Hashimoto’s. That means:

  • Lower risk of thyroid issues
  • More stable energy levels
  • Better overall hormone balance

How Does Vitamin D Support Growth and Repair?

IGF-1 (Insulin-like Growth Factor 1) and Growth Hormone help with cell repair, muscle building, and skin health.

The vitamin D may help raise IGF-1 levels and keep them in a healthy range. And it works the other way too: IGF-1 helps the body make active vitamin D.

It’s like a two-way partnership to help the body recover, grow, and stay strong.

Can Vitamin D Help With Stress Hormones?

Stress hormones come from the adrenal glands. The vitamin D helps manage the enzymes that produce adrenal steroid hormones, including cortisol, the main stress hormone.

What Is SHBG and Why Should You Care?

SHBG (Sex Hormone-Binding Globulin) helps control how much testosterone and estrogen are active in the body. Too much or too little SHBG can cause hormone imbalances.

Some studies show that vitamin D levels affect SHBG, especially in men. This might influence:

  • Muscle tone
  • Mood
  • Sexual health

Can You Still Have Low Vitamin D in Malaysia?

Yes, even in hot, sunny Malaysia, vitamin D deficiency is real. Here’s why:

  • People spend more time indoors
  • Sunscreen blocks vitamin D production
  • Darker skin makes it harder to absorb UV rays
  • Some health conditions affect absorption

So being in a warm climate isn’t a free pass. It’s still smart to check your vitamin D function.

What Are the Signs of Low Vitamin D?

Here are common signs that may hint at a deficiency:

  • Tired all the time
  • Mood swings or sadness
  • Muscles feel weak
  • Colds keep coming back
  • Achy bones or joints

How Can You Boost Your Vitamin D Levels?

Here are simple tips to improve vitamin D levels:

  • Get sunlight for 10-20 minutes (without sunscreen)
  • Eat foods like salmon, egg yolks, and fortified cereals
  • Use supplements if a doctor recommends it

Final Thoughts

Hormones control so much in the body, and the vitamin D hormone is right in the middle of it all. It keeps bones strong, moods stable, fertility supported, and blood sugar balanced.

Think of vitamin D function as a quiet assistant making sure everything runs smoothly behind the scenes. It doesn’t scream for attention, but life feels a whole lot better when it’s in balance.