I know @jakedduck1 that elderly people usually do not get out much into the sunshine so we do not get vit D unless we take it. My doctor prescribed vit D years ago when my vit D tested very low. I am now taking 2000 iu. An iu is really a very small amount. I have never had kidney stones. I will let John answer why his is a little higher.

Hi Jake @jakedduck1 -- I take the D3 - 5000 IU capsule twice a day as part of my neuropathy supplements I found in the closed Facebook Group Solutions to Peripheral Neuopathy Pain & Discomfort - https://www.facebook.com/groups/SPNPD/. They also have a website (http://solutions2pnpd.com/). The D3 is at a therapeutic dosage level which helps get the usable form into the body. Best description I've found that supports the higher dosage is here:

Driving up the dose: implications for high-dose vitamin d therapy - NCBI
-- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824637/

Vitamin D - Doses & Uses
-- https://reference.medscape.com/drug/drisdol-calciferol-vitamind-344417

Dose vitamin D supplementations improve peripheral diabetic neuropathy? A before-after clinical trial.
-- https://www.ncbi.nlm.nih.gov/pubmed/30641826

I get blood labs on a yearly basis as part of my regular checkup.

@jakedduck1 @johnbishop According to my functional medicine doctor, take Vitamin D 3 with K2 because vitamin K prevents the body from depositing calcium. He has tested me, and wants my blood test level over 50. I take Orthomolecular Vitamin K2 D3 which has both in it.