Vitamin D perimenopause deficiency is more common than most women realize. As estrogen declines, your body becomes less efficient at activating vitamin D into its usable form. This means even with the same sun exposure and diet, levels can drop. Low vitamin D can worsen fatigue, mood changes, brain fog, and muscle weakness—symptoms often mistaken for perimenopause itself.

I'm 43, perimenopausal & skeptical—until brain fog & 3am waking changed my mind. My honest, tested supplement guide for hormonal balance & mental health.