Testing of vitamin D3 in single active products

Introduction and scope

Vitamin D plays an essential role in developing, functioning and maintaining healthy bones with severe deficiency causing rickets in children and osteomalacia in adults. People mainly get vitamin D through exposure to sunlight, specifically UVB rays, due to the minimal amounts of vitamin D in most foods (1). To address or prevent deficiencies, many people are guided to take vitamin D oral supplements (2).

The two main forms of vitamin D are ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Most products available in Australia contain vitamin D3 formulated into soft-gel capsules, tablets, effervescent tablets and liquids. However, vitamin D3 is sensitive to air, heat and light, which can affect its stability (3). Because of these known issues, and the importance of vitamin D3 to public health, the Therapeutic Goods Administration (TGA) Laboratories Branch conducted a quality survey of vitamin D3 products.

This survey focused on single-ingredient vitamin D3 products with high sales volumes in Australia between January and December 2023.^[1] The TGA tested 13 of the top-selling products, which were supplied by nine different sponsors.

Testing

Samples

The Laboratories Branch purchased and received samples of listed products from online pharmacies and a registered product from a wholesaler pharmaceutical supplier. Details of the samples obtained for testing are outlined in Appendix A.

Requirements for compliance

For liquid products and the registered tablet product the sponsor’s specifications were applied.

For the remaining samples that were all tablets or capsules, the content limit 90.0 - 165.0% of label claim for oil-soluble vitamins as defined in Schedule 2 in the Therapeutic Goods (Standard for Tablets, Capsules and Pills) (TGO 101) Order 2019 was applied.

Content of vitamin D3

Capsules and tablets were sampled from the primary container, de-identified, packed in labelled containers and protected from light. Liquid samples remained in their primary container but were still de-identified and re-labelled.

The samples were tested for vitamin D3 content by an accredited third-party testing laboratory. Testing was conducted between April and August 2024. The results were recorded as micrograms per 100 grams and converted to percentage of the label claim before being assessed against the relevant requirements.

Results and conclusions

All of the vitamin D3 products tested met the relevant quality standard for active ingredient content. Detailed results for each sample are provided in Appendix A.

Overall, these findings show that the 13 highest-selling vitamin D3 products on the Australian market (January to December 2023) were compliant with TGA requirements for content of active ingredient. This confirms that these products contain appropriate levels of the active ingredient for consumer use.

References

1. Engelsen, O. The Relationship between Ultraviolet Radiation Exposure and Vitamin D Status, Nutrients. 2010, 2(5), 482–495.
2. National Health Institute, https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/, accessed March 2025
3. Al-Hashimi, N.; Abraham, S. Cholecalciferol National Library of Medicine, StatPearls https://www.ncbi.nlm.nih.gov/books/NBK549768/

Appendix A: Details and results of samples analysed

Footnote

1. Based on data supplied by IQVIA to the TGA on Australian sales. Reported December 2023.