The number on a sunscreen bottle is one of the most trusted figures in a bathroom cabinet. Most of us have never had a reason to question it. This year, in Australia, that changed.
The testing story that shook Australian sunscreen
Consumer group CHOICE tested 20 popular sunscreens against their labelled SPF. Only four met their claim; the other 16 came in lower than the number on the bottle (CHOICE, 2025). In the most striking case, a product labelled SPF50+ returned a result of about SPF 4 in that testing. The manufacturer disputes the finding.
These were not obscure brands. They were sunscreens sitting in ordinary shopping baskets. The gap between what the label claimed and what the lab measured is why the phrase "sunscreen SPF testing" moved from industry jargon into everyday conversation. Since then, dozens of sunscreens have been recalled or had their sales paused.
The regulator responded. The Therapeutic Goods Administration ran a consultation on reforming how sunscreens are tested and labelled, including a move toward in-vitro ISO testing and closer oversight of the labs. Submissions closed on 23 May 2026 (TGA consultation).
A single SPF figure carries a lot of weight. It shapes how long people believe they can stay outside and how much they reapply. When that figure is unreliable, the behaviour built on top of it is unreliable too.
Do sunscreens work the way the label says? In-vivo vs in-vitro testing
To understand how a label can be wrong, it helps to understand how SPF is measured in the first place.
The long-standing method is in-vivo testing, which means testing on people. A measured amount of sunscreen goes on a volunteer's skin, and testers compare how much ultraviolet light the skin takes before it visibly reddens, with and without the product. It is a real-world measure, but it depends on the skin, the testers, and the lab conditions on the day. Two labs can return different numbers for the same product.
Newer in-vitro methods, standardised under ISO protocols, measure how much UV passes through a thin film of sunscreen on a synthetic plate, read by an instrument rather than a person. The appeal is consistency, and part of the TGA reform conversation is about leaning on these methods to make the number on the bottle more repeatable from lab to lab.
Neither method is perfect, and the point for a shopper is plainer than the science. The SPF figure is an estimate produced under specific conditions, not a fixed guarantee that travels with the bottle. Knowing that is the difference between reading a label and trusting a label.
What bemotrizinol signals about the pace of change
Here is a detail that puts the system in perspective. In June 2026 the United States FDA added bemotrizinol, a broad-spectrum UV filter already used in sunscreens internationally for years, to its over-the-counter sunscreen monograph, with the order taking effect in August 2026 (FDA). It is reported as the first new sunscreen filter cleared there in about 25 years.
The chemistry available to sunscreen makers, and the rules that govern it, move slowly. That is not a scandal on its own, but it reframes the label question. When both the approved ingredients and the testing standards change this gradually, the responsibility that sits with the person applying the product every day becomes larger, not smaller.
The winter mistake most Australians make
Which brings us to July. In an Australian winter, sunscreen quietly drops out of a lot of routines. The morning is cold, the sky is grey, and the sun feels far away.
What does not drop is UVA. According to bodies like the Skin Cancer Foundation, UVA is present across the year, is barely reduced by cloud, and passes through window glass, whereas UVB is largely blocked by glass and softens more in winter. UVA is also the wavelength most associated with how skin ages in appearance and with uneven tone over time.
So the winter mistake is not a dramatic one. It is a quiet daily omission. The commute by a sunlit window. The overcast walk that felt harmless. The desk beside the glass. None of it registers as sun exposure, and all of it adds up across a season.
Why a tracked daily habit outlasts one-off product faith
If one lesson threads through the testing story, the regulation, and the winter gap, it is this. A single product choice is a weak foundation. A consistent, observed habit is a stronger one.
You cannot personally verify a lab's SPF number. What you can do is notice your own behaviour over time. How many days you actually applied. Whether application fell away when the weather turned. Whether your skin signals show patterns that line up with the seasons you were most and least consistent. Those are observations you can act on, whatever product is on the shelf this month.
The value is not in any single day. It is in the trend across weeks and seasons, which a one-off decision can never show you.
What to do with all this
Three things carry the weight here. Read the SPF label as an estimate rather than a promise. Keep applying through winter, because UVA does not take the cold months off. And track what you actually do over time, so your habit rests on your own record instead of a number you cannot check.
The sunscreen conversation in Australia is not really about one bad bottle. It is about how much faith any of us should place in a claim we did not measure ourselves. The answer is not fear. It is a clearer eye and a steadier habit.
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See where your skin sits today and follow your own trend across the seasons. No routine changes needed to start.
The information in this article is for educational purposes only. Stella is not a medical device and does not diagnose or treat any skin condition. If you have a skin concern, please consult a qualified healthcare professional.
Dr. Alice Rudd
Cofounder · Skin Science · MBBS Monash University
Alice is a cofounder of Stella, where she leads skin science. She trained at Monash University and practised in clinical dermatology before co-founding Stella to develop the metrics framework that underlies the app. She also runs Skindepth, a Melbourne-based dermatology practice.
