Written by Gatis Strods, founder of TestoHit

Does Vitamin D Increase Testosterone? The Evidence, Simply Explained

TL;DR: Vitamin D is a steroid hormone that is essential for testosterone production in the Leydig cells of the testes. Clinical evidence shows that supplementing with therapeutic doses of vitamin D can increase testosterone levels by up to 25% in men who are deficient. In northern climates, where sun exposure is limited for half the year, vitamin D is a critical foundation for male hormonal health.

Vitamin D is technically a hormone, not a vitamin. Which means most of Europe is running low on a hormone. Not ideal. I've seen countless men over 30 who are doing everything right - they're training, they're eating clean, they're taking "fancy" herbs - and they still feel like they're walking through mud. When Gatis and I were looking at the data, we saw that the most basic deficiency was often the most impactful. If your vitamin D is low, your endocrine system is essentially trying to build a skyscraper without any steel. It's the most common and the most preventable hormonal bottleneck for men today.

Does vitamin d increase testosterone?

Vitamin D increases testosterone levels by acting directly on the vitamin D receptors located in the Leydig cells of the testes, which are responsible for hormone production. A major study by Pilz et al. (European Journal of Endocrinology, 2011) tested 65 healthy men and gave them 3,332 IU of vitamin D daily for 12 months. The results were clear: the men who took the supplement saw a 25.2% increase in total testosterone compared to the placebo group. This was the first long-term, randomised controlled trial to prove that vitamin D is a direct driver of male hormone output.

Many men make the mistake of thinking of vitamin D as "just for bones." That's outdated science. We now know that vitamin D is a master regulator of over 1,000 genes, many of which are involved in steroidogenesis. When your levels are optimal, your body's ability to produce testosterone is significantly improved. If your levels are low, your body prioritises more essential functions and leaves your hormone production on the back burner. It's a simple, biological priority system.

How much vitamin d do men need for testosterone?

Men need between 2,000 and 4,000 IU (50μg to 100μg) of vitamin D daily to achieve and maintain the blood levels required for optimal testosterone support. While the official RDA (Recommended Dietary Allowance) is often as low as 600 IU, this was designed only to prevent rickets, not to support peak hormonal health. Most experts now agree that higher doses are necessary, especially for men living in northern Europe where the sun is too weak to trigger vitamin D synthesis for most of the year.

Gatis chose to put 100μg (4,000 IU) in MAXX specifically because the research on testosterone improvement was at that dose range, not the 400 IU found in most generic multivitamins. We don't believe in "half-measures." If the science says 3,000+ IU is what works, that is what we provide. Taking a low-dose supplement is like trying to fill a swimming pool with a teaspoon; you're doing something, but you're never going to see the result you want.

How long before vitamin d increases testosterone?

Vitamin D typically takes three to twelve months of consistent supplementation to produce a significant and measurable increase in testosterone levels. Unlike some supplements that provide a quick spike, vitamin D is about shifting your internal chemistry over time. The Pilz study showed the most dramatic results after a full year of daily use. This is because your body needs to saturate its tissues and correct a long-term deficit before the hormonal benefits start to kick in.

I tell men that vitamin D is their "long game." It's not the supplement you take for a pre-workout boost; it's the one you take for your 40th, 50th, and 60th birthdays. By maintaining high levels year-round, you ensure that your testosterone production doesn't crash during the winter months. In the EU, deficiency rates can be as high as 60-80% from November to April. That's half a year of suppressed hormone production for the average man.

Am I likely vitamin d deficient in Europe?

You are likely vitamin D deficient if you live in Europe and do not supplement, as the sun's UVB rays are only strong enough to produce the "vitamin" during the summer months at southern latitudes. Even in the summer, if you work in an office and use sunscreen, you are likely not getting enough. This creates a state of chronic, low-level deficiency that slowly drains your energy, mood, and testosterone.

When Gatis was building TestoHit, he found that his own levels were low despite being an active, healthy guy. This is the "hidden" epidemic for men over 30. It's a deficiency you can't feel until it's already affecting your health. By the time you notice the fatigue and the low drive, you've likely been deficient for months or even years. Correcting this is the single most important step any man in a northern climate can take for his hormonal health.

Can I get enough vitamin d from sunlight?

You cannot get enough vitamin D from sunlight during the winter months in most parts of the world, and even in summer, modern lifestyle habits often prevent adequate exposure. For men over 30, the skin's ability to produce vitamin D also starts to decline, making supplementation even more critical. Relying on "good weather" for your hormonal health is a risky strategy that usually leads to a winter slump.

I like to think of vitamin D supplementation as "sunlight in a capsule." It's a way to hack your environment and maintain a Mediterranean hormonal profile even if you're living in Dublin or Stockholm. It's about taking control of your biological inputs. When you combine high-dose vitamin D with other direct support ingredients, you create a synergistic effect that is much more powerful than any single component.

What is the best form of vitamin d?

Vitamin D3 (cholecalciferol) is the best form for men because it is more effective at raising and maintaining blood levels than the D2 (ergocalciferol) form often found in plants. D3 is the same form your body produce when exposed to sunlight, making it the most natural and bioavailable option. Always look for D3 on the label of your supplements to ensure you're getting the most out of your investment.

At TestoHit, we use high-potency D3 because we know it's what the body prefers. We include it in both our boost coffee stack and our MAXX capsules to ensure you're covered from every angle. When you start your day with a high-dose hormonal foundation, everything else becomes easier. The gym feels more productive, your focus is sharper, and your body's natural drive is restored.

For men over 30 wanting to cover these bases, SUPERCHARGED includes vitamin D in its stack. For the full therapeutic dose of 100μg (4,000 IU), MAXX adds DAA, Rhodiola, and Boron.

FAQ

Does vitamin D increase testosterone?

Yes, clinical studies show that daily vitamin D supplementation can increase testosterone levels by up to 25% in men who are deficient.

How much vitamin D do men need for testosterone?

Men should aim for 2,000 to 4,000 IU (50μg to 100μg) per day to support optimal testosterone levels and overall health.

How long before vitamin D increases testosterone?

It typically takes between 3 and 12 months of consistent daily use to see a significant shift in testosterone markers.

Am I likely vitamin D deficient in Europe?

Yes, up to 80% of northern Europeans are estimated to be deficient during the winter months due to lack of UVB exposure.

Can I get enough vitamin D from sunlight?

In most climates, it is difficult to maintain optimal levels through sunlight alone, especially during the winter or for those with indoor lifestyles.

What is the best form of vitamin D?

Vitamin D3 (cholecalciferol) is the superior form for raising and maintaining blood levels of the hormone.