Yuka gave our sunscreen 0/100.
Here’s why we think that’s dangerous.

To any normal person, that communicates something pretty obvious: this product is dangerous. Don’t use it.

Sunscreen is a heavily regulated therapeutic product in Australia, and ingredient safety is continually reviewed as the evidence develops. The TGA says the benefits of sunscreen continue to far outweigh any risks, and that sun protection — including sunscreen — remains one of our most important tools for preventing skin cancer. ^[10]

UV radiation itself is a Group 1 carcinogen, just like asbestos and tobacco smoke. Skin cancer is so deeply embedded in Australia’s health burden that it’s considered our “national cancer”, and Australia is considered the “skin cancer capital of the world”. ^{[11] [12]}

These ingredients are studied, reviewed and re-reviewed for a reason: to work out what can be used safely while helping prevent people getting cancer.

So when an app gives an Australian SPF50+ sunscreen a bright-red zero, we think it is fair to ask:

That wording matters.

Yuka is not presenting itself as a quirky ingredient dictionary. It explicitly markets itself as a tool that analyses the health impact of products and helps consumers make healthier decisions. ^[1]

That creates an enormous amount of implied authority behind a score like 0/100.

So we emailed Yuka.

We didn’t jump straight online and complain. We contacted them.

We explained that Naturally Cooked is an Australian therapeutic SPF50+ sunscreen, asked why it was receiving a 0/100 score, and raised our concern that this style of rating could frighten consumers away from sunscreen.

Yuka replied.

And their response made the problem much clearer.

First, Yuka acknowledged that sunscreens approved through the Australian regulatory process are considered safe under those standards.

Then came the much more revealing part.

Something doesn’t really line up.

Yuka told us directly that its approach is to alert consumers to the presence of what it considers a controversial ingredient, rather than make a judgement about the product’s safety in terms of concentration.

Yuka does make general assumptions around population exposure. Its methodology says ingredient evaluations can consider estimated concentrations, typical product use, cumulative exposure and absorption. ^[2]

And Yuka still does not know the actual concentration of the ingredient in the specific finished sunscreen it is assigning a precise score to.

The consumer sees a precise whole-product verdict. The methodology is not a finished-product-specific risk assessment.

Yuka uses real science. That doesn’t make the score scientifically sound.

This is worth being very clear about: we are not accusing Yuka of fabricating scientific papers. Many of the studies it cites are perfectly real. The issue is what happens between the study and the giant red score on somebody’s phone.

Toxicology studies are often designed to establish where effects occur. That can involve high doses, unusual exposure routes, long treatment periods, cell models, animal studies and deliberately conservative experimental conditions.

Discovering that an effect exists somewhere in that evidence is the beginning of a safety assessment, not the end of one.

You then need to ask what actually matters for people using the product: what dose, what concentration, what route, how much is absorbed, how frequently is it used, and how far is real-world exposure below the toxicological reference point?

Importantly, neither regulator ignored endocrine concerns.

The TGA said available data for several sunscreen actives, including octocrylene, indicated potential endocrine effects, but that the evidence was not adequate to establish causality in humans. ^[4]

The SCCS similarly considered potential endocrine-disrupting properties before reaching its concentration-specific safety conclusion for octocrylene. ^[5]

That’s the difference between identifying a potential hazard and actually assessing risk.

The “natural = safe” shortcut doesn’t help either.

A lot of modern cosmetic fear runs on a simple idea:

Natural good. Chemical bad.

It sounds intuitive. It is not a toxicological principle.

UV radiation is natural. It causes skin cancer.

Poisonous plants are natural. Arsenic occurs naturally. Some of the most potent toxins known to humans occur naturally.

“Natural” tells you something about origin. It does not tell you whether something is safe at a given dose.

Yuka’s own endocrine-disruptor advice includes recommendations to favour “natural” cleaning products and “organic cosmetics”. ^[3] In our view, that feeds directly into the appeal-to-nature framing already dominating sunscreen misinformation online.

“We’re not telling people not to wear sunscreen.”

That was another part of Yuka’s response to us.

But communication does not work like that.

If somebody scans their sunscreen and sees:

0/100.
BAD.
HIGH-RISK.

What are they meant to conclude?

That everything is fine? That the app thinks they should confidently continue using that sunscreen?

Of course not.

And this is where Yuka’s own data becomes especially awkward.

This is why we believe it becomes a public-health issue.

Yuka says it is not telling consumers to avoid sunscreen.

Its own research says red ratings change consumer behaviour.

We also see people online using these scores to conclude that chemical sunscreens are dangerous.

There is no study showing that Yuka specifically causes a measurable percentage of people to stop wearing sunscreen.

We are not pretending there is.

But we do not think this requires an enormous leap of logic.

In Australia, where UV radiation is a known carcinogen and skin cancer remains an enormous public-health burden, we believe that is dangerous.

And dramatic scores are extremely good at spreading.

In 2022, a TikTok showing a shopper scanning familiar hair products with dramatically different Yuka scores went viral.

Yuka co-founder Julie Chapon later described that video to Glossy as the watershed moment for the company’s international expansion: “[Our global expansion all] started with that video.” ^[8]

That does not prove Yuka designed its methodology with the explicit intention of frightening people.

We cannot know what conversations happened internally.

But as business owners, the commercial dynamic is not difficult to understand.

The problem is that the confidence exceeds what the methodology can actually support.

So what should you actually trust?

Not us simply because we sell sunscreen.

Check us.

Read the regulator assessments. Read the scientific committee opinions. Look at the studies.

And when somebody tells you an ingredient is dangerous, ask:

A study can be real and still be communicated badly.

A potential hazard can be real and still not make the finished product dangerous.

And a score out of 100 can look incredibly scientific while communicating far more certainty than the underlying evidence actually supports.