Vitamin D Improves Mental Health and Memory Skills.

In 2025, Aleksandra Skoczek-Rubińska and a team from Poznan University of Physical Education reviewed 13 studies from 2009-2025 on how vitamin D helps BDNF (a brain protein for nerve growth), mood, and thinking in adults. They looked at human and animal studies from big databases to see how vitamin D levels or supplements affect people’s brains and feelings.

Taking 2000 IU or more of vitamin D daily for 12 weeks raised BDNF by 7-15% and cut depression symptoms by up to 7.6 points on a mood scale, especially in people low on vitamin D (under 30 ng/mL). Higher vitamin D (up 10 ng/mL) also improved memory and thinking scores by 0.6 points. In animals, vitamin D boosted BDNF by 20-30% and improved memory behaviors by 15-25%, helping fight stress effects.

If your vitamin D is low, take at least 2000 IU daily to help your mood and brain, but check with a doctor first.