D vitamin

Vitamin D, the best winter supplement?

Is Vitamin D the best supplement you can use at this time?

For those who live in Portugal, it's easy to get good levels of Vitamin D in summer.

In the winter?

Not really.

While in summer we have a favorable climate to achieve good values of this vitamin, in winter the sun appears less, and with less intensity.

The days are also shorter and the probability of a failure increases significantly.

This is where vitamin D supplementation comes in.

What is Vitamin D?

Vitamin D is one of the 24 micronutrients essential to humans, and can be ingested or synthesized by the skin.

While in hot seasons it is easy to get good levels of Vitamin D, in winter the story changes.

The body produces this vitamin through cholesterol, but it needs sun exposure to do so.

If there is no sun exposure, you need to ingest it through food, or supplementation.

Unfortunately, it is difficult to achieve good values of this vitamin through food.

Milk fortified with this Vitamin normally provides about 30 IU per 100 ml.

The egg yolk?

Less than 50 IU.

On the other hand, salmon, depending on their cultivation, can reach 300/400 IU, and sardines approximately 200 IU.

Basically, just relying on food to get good levels of this vitamin is not a good strategy and you'll see why.

D vitamin

What does Vitamin D do?

Vitamin D influences many processes in the human body.

It is associated with the immune system and a reduction in the likelihood of contracting certain health problems.

It is also essential for bone health and plays an important role in well being, with low levels of this vitamin being associated with symptoms of bad mood and depression.

As if that were not enough, it is also very important for the hormonal system, with a strong influence on testosterone levels.

Does Vitamin D increase Testosterone?

Testosterone is one of the main hormones when it comes to gaining muscle mass and losing fat.

High levels lead to more strength and muscle mass, low levels lead to increased fat, little energy and difficulty in gaining muscle.

In winter, the levels of this vitamin go down, after all, the sun goes on vacation.

When Vitamin D levels are low, Testosterone levels go down.

When vitamin D supplementation is introduced in people with low levels of this vitamin, testosterone levels go up.

Vitamin D and Testosterone

In a study of 2,299 participants, all of them men, they measured the values of Vitamin D, Testosterone and SHBG.

In addition, they also examined whether androgen levels varied seasonally.

That is, they verified whether in the summer these values are higher and whether in the winter they are lower, or not.

The results?

Men with sufficient levels of vitamin D had significantly higher levels of testosterone and androgens compared to those who had insufficient levels of this vitamin.

In addition, SHBG levels were also significantly lower in those who had sufficient Vitamin D compared to the rest.

Finally, the time of year when Testosterone levels were highest?


Vitamin D Supplementation

In another study of 54 healthy but overweight men, testosterone levels were measured while on a weight reduction program.

For one year, 31 of them received 3,332 IU of Vitamin D per day, while 23 did not.

At the start of the study, both groups had low Vitamin D levels (below 20 ng / mL) and Testosterone levels were also low.

The group that used the supplementation, unsurprisingly, saw their Vitamin D levels increase.

However, it was not just the levels of this vitamin that increased.

The group using Vitamin D supplementation saw their total testosterone increase by about 25%, their bioactive testosterone at 19% and free testosterone at 20%.

The group that did not use supplementation, however, had no significant changes in any of these areas.

vitamin d testosterone

Recommended doses

The recommended daily dose in Portugal is only 200 IU.

This is an extremely low value (1), especially considering the number of factors that can influence the levels of this vitamin in the body.

In Germany (2) and the United States (3), the recommended daily dose has recently been changed to 800 IU.

But after all, we are in Portugal, a country with a much warmer climate than Germany.

We don't need as much Vitamin D as they do, right?


In 2005, a study (4) was carried out to assess vitamin D levels in the population of South Florida.

South Florida, in which the largest city is Miami, is located in the United States, and enjoys a tropical climate, that is, immense sunshine throughout the year.

For that, data were collected from 212 people, both men and women, at the end of the winter period.

The results?

38% of men and 40% of women had insufficient values of this vitamin.

vitamin D supplement

Ideal doses

The recommended doses serve as a minimum value to avoid serious health problems.

This does not mean that they are the ideal doses.

The ideal minimum value in the body is 20 ng / mL, with the recommended value being around 30 ng / mL of 25 (OH) D.

These values are obtained through analysis, so if you want to know your values accurately, you must measure the levels of 25 (OH) D.

There are several factors that influence the levels of Vitamin D in the body, so it is impossible to suggest a perfect value for everyone.

However, the main factor is undoubtedly the sun exposure.

A person living in Sweden needs to ingest greater amounts of this vitamin than someone living in the Canaries.

What dose do I use then?

You should eat at least 1000 IU of Vitamin D3 per day, and always with a meal with some fat.

However, in order to reach the ideal values, especially in winter, the intake must be higher.

Between 2000 to 4000 IU of Vitamin D3 per day is an interesting value for most of the population.

You can also calculate an approximate value using your body weight, multiplying your current weight by a value between 20 to 60 IU.

In addition to sun exposure, factors such as skin tone, the use of sunscreens (5) and latitude influence the conversion of this vitamin in the body.

Darker skin tones need more sun exposure and the use of sunscreens reduces the production of Vitamin D in the body.

Finally, you should not exceed 10,000 IU.


Going from an insufficient level of this vitamin to an adequate level leads to an increase in Testosterone.

This does not mean that by using more you will get higher levels of this hormone.

You should aim to achieve and maintain optimal levels of Vitamin D, not excessive and harmful levels.

In addition, these values are for healthy people, so if you have a health problem, you should always inform yourself first about your specific case.

Ideally, you will always have tests to know your levels of this vitamin. Ideal and simple too.

Just ask any doctor when you go for tests to add this assessment, or simply do it yourself at any test clinic asking for an assessment of Vitamin D levels.

This allows you to customize your Vitamin D supplementation, rather than going on hunches.

Vitamin D supplements

First of all, you should choose a vitamin D3 and not a D2 supplement, as the body uses it more efficiently.

Then, you must take into account the quantity you want to use and the price.

Here are two products with a good price/quality ratio.

You also have the Myprotein offer, with 2500 IU per capsule, but what for 10.99? brings with it 180 capsules.

Finally, do you have Zumub's Vitamin D3, which at 2000 IU per capsule and a value of 4.99? for 120 capsules, it is also an excellent bet.

You can also use the code GVIRTUAL and get a discount of 10% on your entire order.

Is available here.

Whatever your choice, you are certainly well served.

vitamin d capsules


Vitamin D plays an important role in various processes in the body, with the hormonal system being one of them.

Basically, in winter it is easy to drop the levels of this vitamin to insufficient levels, and correcting that will increase your Testosterone.

Hence the importance of this supplement this season.

Not only will it help you in the gym, but also outside of it, as the benefits of vitamin d are immense.

In the summer, although it is equally important to have good levels of this vitamin in the body, you can easily reach them through sun exposure, which makes supplementation in many cases unnecessary.

So, is Vitamin D the best winter supplement?



Vitamin D and Testosterone
Wehr E, Pilz S, Boehm BO, März W, Obermayer-Pietsch B. Association of vitamin D status with serum androgen levels in men. Clin Endocrinol (Oxf). 2010Aug; 73 (2): 243-8.
Vitamin D supplementation
Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011 Mar; 43 (3): 223-5.
(1) Whiting SJ, Green TJ, Calvo MS. Vitamin D intakes in North America and Asia-Pacific countries are not sufficient to prevent vitamin D insufficiency. JSteroid Biochem Mol Biol. 2007 Mar; 103 (3-5): 626-30.
(two) https://www.dge.de/wissenschaft/referenzwerte/vitamin-d/
(3) http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm385663.htm
(4) Levis S, Gomez A, Jimenez C, Veras L, Ma F, Lai S, Hollis B, Roos BA. Vitamin d deficiency and seasonal variation in an adult South Florida population. J Clin Endocrinol Metab. 2005 Mar; 90 (3): 1557-62.
(5) Matsuoka LY, Ide L, Wortsman J, MacLaughlin JA, Holick MF. Sunscreens suppresscutaneous vitamin D3 synthesis. J Clin Endocrinol Metab. 1987 Jun; 64 (6): 1165-8.

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