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Vitamin D deficiency - the silent energy killer
Got my bloodwork done and my vitamin D was at 18 ng/mL (should be 30-50+). Doctor said this could explain my fatigue, brain fog, and mood issues I've been dealing with for months. I work from home and barely get outside during winter so I guess its not surprising but I had no idea it could affect this much.
Anyone else discover they were deficient? How long did it take to feel better after supplementing?
Mine was at 12 when I got tested. TWELVE. I was basically a zombie for months thinking I was depressed (and maybe I was, partly because of the deficiency). Doctor put me on 50,000 IU weekly for 8 weeks then switched to 5,000 IU daily maintenance.
Started feeling better around week 3-4. By week 8 it was night and day. Energy was back, brain fog lifted, even my mood improved significantly. Get retested in 3 months to make sure your levels are coming up.
This is SO common especially for guys who work office/remote jobs. I'd bet money half the people on this forum are deficient and don't know it. Get your levels checked people - its a simple blood test and the fix is a cheap supplement.
Take it with a fat source (meal, fish oil, etc) for better absorption. This made a big difference for me - my levels barely moved until I started taking D3 with my breakfast eggs instead of on an empty stomach.
Also check magnesium while you're at it. Vitamin D needs magnesium to be properly utilized and a lot of guys are low on both. I take D3 + K2 + magnesium glycinate. The trifecta.
Coming at this from the evidence side (not a clinician — please don't take supplement timing as medical advice). The "silent energy killer" framing is a little stronger than the data supports — D deficiency does correlate with fatigue but the causal arrow on supplementation → energy improvement is messier than the popular framing suggests.
What's solid: if your 25(OH)D is below ~20 ng/mL, supplementing to get above 30 is a reasonable thing to do, and most people in northern latitudes in winter are below 20. My own last reading was 22 and I'm in the Northeast so I'm in that camp.
What's weaker: the dose-response curve flattens above ~30 ng/mL and there's no clear evidence that pushing higher does anything for energy. The mega-dose IV-D protocols some functional med folks push aren't supported by the literature I've read.
Get a level checked first. 5,000 IU/day is a normal supplementation dose for an adult who's deficient. Don't take 50,000 IU/week unless a doctor told you to.
— Priya Sharma (neuro + supplements, contributor)
Coming at this from the evidence side (not a clinician — please don't take supplement timing as medical advice). The "silent energy killer" framing is a little stronger than the data supports — D deficiency does correlate with fatigue but the causal arrow on supplementation → energy improvement is messier than the popular framing suggests.
What's solid: if your 25(OH)D is below ~20 ng/mL, supplementing to get above 30 is a reasonable thing to do, and most people in northern latitudes in winter are below 20. My own last reading was 22 and I'm in the Northeast so I'm in that camp.
What's weaker: the dose-response curve flattens above ~30 ng/mL and there's no clear evidence that pushing higher does anything for energy. The mega-dose IV-D protocols some functional med folks push aren't supported by the literature I've read.
Get a level checked first. 5,000 IU/day is a normal supplementation dose for an adult who's deficient. Don't take 50,000 IU/week unless a doctor told you to.