Vitamin D

Vitamin D


When someone tells you that getting sunlight is good for your health, they aren’t lying. The primary benefit of sunlight is vitamin D. Often referred to as “the sunlight vitamin”, it is currently one of the most underutilized nutritional supplements for cognitive and physical health.

The majority of people in the western world live in regions where sunlight is inconsistent during many months of the year [1]. Because of this, supplementation (whether via fish products or pure vitamin D supplements) is often advised.

The benefits of vitamin D are plenty, but the brain is one of the biggest benefactors. Studies show increased cognitive abilities with adequate vitamin D [2], there is evidence vitamin D regulates serotonin and thus influences anxiety and depression [3].

Also Known As

Cholecalciferol (Vitamin D3), Ergocalciferol (Vitamin D2)

Editors’ Thoughts on Vitamin D

Between living in Texas, taking 2 – 3 grams of fish oil daily, and eating fish most days of the week, I don’t feel the need to supplement with vitamin D specifically. However, I do see the advantage.

Besides vitamin D, there are few supplements I would recommend for anyone and one of them is fish oil. Luckily, there are many fish oil supplements (like Nordic Naturals) that have vitamin D in them. I would try to combine both of these as best as possible especially if I was living in more northern climates.

From my understanding, it only takes 10 – 15 minutes of UV radiation from the sun (even in the shade) to provide an adequate day’s worth of vitamin D, but it wouldn’t hurt to have a supplement on hand in the event of sustained overcast.

I also particularly like Examine editor Herman Gill who wrote “If there’s only one supplement you’re taking for your health and your diet is decent, it should probably be vitamin D. I highly recommend taking vitamin D instead of a multivitamin most of the time.

More confirmation this is essential.

Mansal Denton, Nootropedia Editor

vitamin d

Benefits of Vitamin D

The benefits of vitamin D range from enhancing cognitive performance to reducing neurological decline and even supporting healthier mood (reducing symptoms of anxiety and depression).

One animal study showed that long-term treatment of vitamin D could help slow the rate of decline in the hippocampus (where memories are stored) showing promising neuroprotective effects [4]. This may be one of the correlations between vitamin D and neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s.

Some studies show that vitamin D supplementation could reduce symptoms of Alzheimer’s disease [5] and there is an inverse relationship between serum vitamin D and risk of Alzheimer’s disease [6]. The same inverse relationship exists with Parkinson’s disease [7].

Unfortunately, when adults were tested (who had sufficient vitamin D levels), the addition of 5000 IU of vitamin D failed to influence any cognitive indicators [8]. Therefore, some could conclude that vitamin D is a liability when one is deficient, but is not necessarily much of a cognitive asset in high quantities.

Of course, one of the main benefits of vitamin D is related to mood and particularly anxiety and depression. One study showed that depressed adults deficient in vitamin D were able to decrease symptoms by 42% [9]. There seems to be ample evidence against this hypothesis as well, but recent research shows a potential mechanism for improved mood and reduced anxiety.

In a 2014 dated study, Dr. Rhonda Patrick showed that vitamin D is required for regulating serotonin [10]. While her study focused on how this might help reduce symptoms of autism, it is nevertheless interesting given the context of mood and reduced anxiety.

Side Effects of Vitamin D

While vitamin D is largely healthy and recommended for anyone who is deficient, there are potential side effects. One side effect of vitamin D can be related to overdosing. Toxicity from vitamin D can be lethal, which is why recommended doses should not exceed 10,000 IU daily.

Another study (meta-analysis) showed that elderly women had a higher risk for vitamin D when paired with calcium. The sample size was nearly 75,000 people and there was a significant increased risk of kidney stones [11].

Overall, most people consider vitamin D to be harmless without many side effects. However, these toxicity and safety concerns are important.

Vitamin D Dosage

The proper vitamin D dosage in healthy adults will depend on a number of factors including geography and outside activity. The standard dosage is around 1 – 2000 IU of vitamin D3, but this is at the lower end of the range.

The upper bound is around 10,000 IU per day, though it might be best to stick to doses under 5000 IU. Finally, vitamin D is supplemented via cholecalciferol (D3) and is best taken with a fat source like fish oil (which is why they are often together).

How and Where to Buy Vitamin D

As mentioned above, you can buy vitamin D in many locations both online and at your local health food store. There are many sources of vitamin D online, but it may be most effective to purchase both fish oil and vitamin D together.

We recommend either the vitamin D from Pure Nootropics (one of our recommended vendors) or you can find the Nordic Naturals omega-3 + vitamin D3 product that combines the two.

Selected Community Experiences

Now I take 8000IU every morning and I can't believe how strong the effects are. I feel like I'm slightly tripping, also a bit drunk and dissociated. I can function fairly well…” [12] – Henzington

I've already been taking 5000 IU and decided to take 20000 IU to see what would happen in case I had an absorption problem and wasn't getting enough before. Over the day my thoughts began racing and started to develop intense anxiety and strong flight instincts. From everything I've read I thought vitamin D was anxiolytic so I was confused to why this was happening. I developed a little anxiety before when taking 5000 IU a day but I discounted it as a nocebo. I wanted to recreate the strong mood boost I had received one day after I had basked in the sun and I suspected it might have been due to a vitamin D deficiency. Now I'm not sure what's going on” [13] – TheLegendaryTakadi

References (Click to Expand)
  1. //
  2. //
  3. //
  4. //
  5. //
  6. //
  7. //
  8. //
  9. //
  10. //
  11. //
  12. //
  13. //


Nootropedia is meant to be a resource for individuals researching drugs and supplements that are good for brain health, otherwise known as nootropics, and thus we are the Nootropics Encyclopedia. Because of our in-depth coverage of this topic, our community has requested that we cover other brain health topics and "lifehacks" so that has become the focus of Nootropedia.