References and Sources

This page lists the standards, regulatory guidance and published research the content of this guide is based on. Each section names the pages it supports.

Where a testing standard is cited, it is the standard that governs how the number on a product label is produced. Standards are revised periodically, and labelling rules differ between markets — so an SPF or UPF figure is not always directly comparable between countries.

Sunscreen testing and labelling

Supports SPF, Sunscreen Facts and Types of Sunscreen.

  • International Organization for Standardization. ISO 24444: Cosmetics — Sun protection test methods — In vivo determination of the sun protection factor (SPF). The method behind the SPF number on a label.
  • International Organization for Standardization. ISO 24443: Cosmetics — Sun protection test methods — In vitro determination of sunscreen UVA photoprotection. The basis of UVA and broad-spectrum claims.
  • United States Food and Drug Administration. 21 CFR 201.327 — Over-the-counter sunscreen drug products: labeling and effectiveness testing. Sets the US rules for "broad spectrum", water-resistance times, and the prohibition on the terms "waterproof" and "sweatproof".
  • United States Food and Drug Administration. Sunscreen: How to Help Protect Your Skin from the Sun. Consumer guidance on SPF, broad spectrum and water resistance.

Sunscreen ingredients and filter safety

Supports Sunscreen Ingredients.

  • Matta MK, et al. Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. JAMA, 2019. Established that several organic filters are absorbed systemically; the authors note absorption alone does not establish harm.
  • Matta MK, et al. Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. JAMA, 2020. Follow-up study across additional filters and formulations.
  • United States Food and Drug Administration. Proposed rule and status of sunscreen active ingredients (GRASE determinations). The regulatory position on zinc oxide and titanium dioxide versus filters requiring further safety data.

Application, reapplication, storage and expiry

Supports Sunscreen Tips and Sunscreen Effectiveness.

  • American Academy of Dermatology. Sunscreen FAQs and How to apply sunscreen. Source of the standard guidance on quantity, reapplication every two hours, and reapplication after swimming or towelling.
  • International Organization for Standardization. ISO 24444. Defines the 2 mg/cm² application density used in SPF testing — considerably more product than most people apply in practice, which is why real-world protection is usually lower than the label figure.
  • United States Food and Drug Administration. Sunscreen labelling requirements on expiry and storage. Basis for guidance on shelf life and on protecting product from prolonged heat.

Sunscreen for children and infants

Supports Sunscreen for Children.

  • American Academy of Pediatrics. Sun safety guidance for infants and children. Source of the position that infants under six months should be kept out of direct sun and protected by shade and clothing, with sunscreen used on small exposed areas only where shade is not available.
  • American Academy of Dermatology. Sunscreen guidance for children, including the preference for mineral filters on sensitive skin and cautions on spray formats.

Sun-protective clothing and UPF

Supports UPF, Sun-Protective Clothing and Sun Protection Fabric.

  • Standards Australia / Standards New Zealand. AS/NZS 4399: Sun protective clothing — Evaluation and classification. The classification scheme behind UPF 15, 30, 50 and 50+ labelling.
  • AATCC. TM183: Transmittance or Blocking of Erythemally Weighted Ultraviolet Radiation through Fabrics. The test method used to measure how much UV a fabric transmits.
  • ASTM International. D6544: Standard Practice for Preparation of Textiles Prior to Ultraviolet (UV) Transmission Testing. The durability protocol — repeated laundering and simulated sunlight exposure — that a garment must survive before it is rated, so the UPF figure reflects a used garment rather than a new one.

Ultraviolet radiation and the UV Index

Supports several pages, including guidance to judge risk by UV Index rather than temperature.

  • World Health Organization, World Meteorological Organization, UNEP and ICNIRP. Global Solar UV Index: A Practical Guide. The international basis of the UV Index and the exposure categories used with it.
  • World Health Organization. Radiation: Ultraviolet (UV) radiation and skin cancer. Background on UVA and UVB and their respective roles in burning and long-term damage.

Vitamin D and sun exposure

Supports the vitamin D section of Sunscreen Facts.

  • Neale RE, Khan SR, Lucas RM, Waterhouse M, Whiteman DC, Olsen CM. The effect of sunscreen on vitamin D: a review. British Journal of Dermatology, 2019. Concludes that sunscreen use in real-world conditions has not been shown to cause vitamin D deficiency.

Melanoma recognition

Supports ABCDE Rule for Skin Cancer.

  • American Academy of Dermatology. What to look for: ABCDEs of melanoma. The recognition criteria set out on that page.
  • Skin Cancer Foundation. Melanoma Warning Signs and the ABCDEs. Includes the "ugly duckling" sign.

These are recognition criteria only. They do not diagnose melanoma and they do not exclude it — some melanomas do not fit the pattern. Any new, changing or unusual lesion should be assessed by a doctor.

History of sunscreen

Supports Who Invented Sunscreen?

  • Franz Greiter — Austrian chemist, credited with Gletscher Crème (1938) and with proposing the Sun Protection Factor concept in the 1970s.
  • H. A. Milton Blake — South Australian chemist who produced an early commercial sun preparation in the 1930s, the origin of Hamilton Laboratories.
  • Eugène Schueller — founder of L'Oréal, who launched Ambre Solaire in 1936.
  • Benjamin Green — American airman and pharmacist associated with the wartime "Red Vet Pet" preparation that led to Coppertone.

Credit for inventing sunscreen is genuinely contested. Several people developed comparable products independently in the 1930s and 1940s, and the guide presents the competing claims rather than settling on one.

National sun protection guidance

Ultraviolet levels vary widely by location, and national bodies differ in their specific recommendations. Readers should check the guidance issued for where they live:

  • Cancer Society of New Zealand and SunSmart New Zealand.
  • Cancer Council Australia.
  • American Academy of Dermatology and the Skin Cancer Foundation (United States).
  • NHS and the British Association of Dermatologists (United Kingdom).

Information on this website is provided for general educational purposes and is not a substitute for individual medical advice or assessment by a qualified healthcare professional.

© 2026 Sun Protection and Products Guide