John, I can't thank you enough for the information you have shared. You're very knowledgable and generous in sharing it. I will increase my intake, I had been taking 3000 IU. I've had three serious viral infections: mono, herpes, and shingles. Shingles has just appeared this year, and the doctor told me the count was very high. I've never made a correlation between these and the problems with my ears, or my neurological issues. Of late I can hardly read. The print blurs, my eyes burn, and my head hurts. Tomorrow I see my Neurotolgist. Hoping to get some relief. Thanks again.
One microgram (mcg, or µg) of vitamin D is 40 IU. So, if you have 25 µg, that's 40 x 25 = 1000 IU. You need to be taking 5000 IU. Take five of these a day (until you run out, then buy some 5000 IU softgels). --John of Ohio