Over the past year there has not only been a handful of new ISO standards released, but sunscreen formulas have changed too. Due to the latest standard released, ISO 24444, Solar Light has made some changes to our stock of standards.

• P7- This standard is no longer available. Under ISO 24444, any testing for SPF 25 and below will be covered using P2 or P3.

• P5- Average SPF value = 31. Acceptance limits = 23.7-37.4 SPF. This will be used under ISO 24444 for testing SPF values in the middle range of SPF 26-49.
• P8- Average SPF value = 63. Acceptance limits = 43.9-82.3 SPF. This will be used under ISO 24444 for testing SPF values in the high range of SPF 50 and up.

With the new update, in vivo SPF experiments will use standards based off three categories: low, middle, and high. If the estimated SPF is under 25, then all subjects use P2 or P3 as a standard. When the estimated SPF is 25 or more, but less than 50, ISO requires at least five people use the mid-range standards: P5 or P6 (N/A) with the rest using P2/P3. Finally, at SPF 50 and above ISO requires at least five people use the high range standard P8, with the rest using P2/P3. Spreading times are now only 35s +/-15s with the technique requiring small individual circles followed by alternating vertical and horizontal lines.