NMA: Nonprescription Medicines Academy

Vitamin D Supplements Vary Widely in Potency

April 17th, 2013

In an analysis of marketed nonprescription vitamin D3 supplements and compounded supplements, the cholecalciferol content was found to be highly variable, with potency ranging from 9% to 146%.

Analyses were conducted on the following samples:

  • Five pills from 15 sealed bottles of nonprescription vitamin D3 supplements (1,000 IU, 5,000 IU, and 10,000 IU) purchased at five stores in Portland, Oregon.
  • One pill from five bottles of nonprescription vitamin D3 supplements with the same lot number, and one pill from five bottles with different lot numbers.
  • Cholecalciferol tablets (1,000 IU and 50,000 IU) compounded at the authors’ institution on three occasions over 4 months. Testing was done at variable times (0-6 months) after compounding.

Potency was analyzed using high performance liquid chromatography.

The nonprescription supplements contained 52% to 135% of the expected dose. The one manufacturer that was USP verified was highly accurate (101.7%), and all 5 pills tested were within 10% of expected dose.

The compounded tablets intended to provide 50,000 IU of cholecalciferol contained 52% to 105% of the expected dose. The tablets intended to provide 1,000 IU contained 23% to 146% of the expected dose.

JAMA Intern Med. 2013 Feb 11:1-2. [Epub ahead of print]