Table 1.

Classification of 26 Vitamin A-containing Acne Supplements Sold Online

Dosage Criteria	No. of Supplementsb
1. High doses of preformed vitamin A.a ≥ 3,000 mcg RAE or more, which is the UL for preformed vitamin A in adults ≥ 19 years as well as a potentially teratogenic dose [1,2]	3
2. High doses of vitamin A precursors. a >900 mcg RAE, the RDA of vitamin A (both preformed and precursors) for males ≥ 14 years [2]	4
3. Unknown risk
Information in mcg RAE provided, but not enough information available to calculate IUs	2
Information in IUs provided or can be calculated, but teratogenicity risk unknown because form of vitamin A or relative proportions of vitamin A forms not specified. >10,000 IU vitamin A	3
Information in IUs provided, but not enough information to convert to mcg RAE	3
Confusing labeling	4
Labeling with discrepancies	3
Dosage not specified	1
4. Low doses of vitamin A
For females. <700 mcg RAE (both preformed and precursors), which is the RDA for females ≥14 years [2]	6
For males. <900 mcg RAE (both preformed and precursors), which is the RDA for males ≥14 years [2]	9

IUs = international units; RAE = retinol activity equivalents; RDA = recommended daily allowance; UL = tolerable upper intake level.

^aMeasured by mcg RAE or IUs.

^bSome supplements were placed into more than one category