Walk into a pharmacy in Europe, Japan, or Australia and you’ll find a sunscreen ingredient that protects skin from the signs of aging better than almost anything sold in the United States — without the absorption questions that hang over other sunscreen filters. It has been on shelves overseas since the 1990s, yet until a few weeks ago Americans effectively couldn’t buy it. Not because anyone found it dangerous, but because of an unintended consequence of a law passed in 1938. Here is what that ingredient is, why it was kept out, and what just changed.
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What America was locked out of
The ingredient travellers brought back in their suitcases has a name: bemotrizinol. It’s a sunscreen filter — one of the chemicals that soaks up the sun’s rays before they hit the skin, protecting against photoaging. And it does two things that, until now, couldn’t be found together in one bottle in America.
The first is that it doesn’t pass from the skin into the bloodstream. To see why that matters, it helps to know what the alternative does.
There are two kinds of sunscreen filters. The mineral ones — zinc oxide and titanium dioxide — mostly sit on top of the skin [1]. The chemical ones — names like avobenzone, oxybenzone, octocrylene — soak in. The chemical ones are in most of the bottles on the shelf because they go on nicer and rub in clear.
Here’s the part that surprises people. The FDA ran its own studies on those chemical filters to see how they behave on the skin. The filters didn’t stay on the skin — they crossed into the bloodstream, past a level the FDA uses to decide whether a chemical needs the full battery of long-term safety studies. Several crossed it on day one [2].
To be clear, this does not mean those products are dangerous. The FDA’s point is that higher absorption means higher potential impact, which calls for a higher standard of evidence to confirm the chemicals are safe — evidence that does not yet exist [2]. The FDA’s own advice is to keep using sunscreen while that data is sorted out. For anyone who would rather not routinely rub something into their skin while the data is incomplete, that is the appeal of filters that don’t soak in.
Bemotrizinol is one of those filters, and the reason it barely absorbs isn’t magic — it’s mostly size. Most chemical filters are small molecules, small enough to slip between skin cells and work their way into the bloodstream, which is exactly what those FDA studies caught them doing. Bemotrizinol is a giant by comparison — its molecular weight is about 628, more than twice the size of a filter like oxybenzone at 228 [3][4].
There’s a well-known rule of thumb in skin science: once a molecule gets much heavier than about 500, it simply can’t push through the outer layer of the skin. Bemotrizinol is well past that line [5].
It has two other key features. First, it protects against the deep rays — the long-wave UVA that ages skin and that many US “broad spectrum” products quietly under-block. Independent testing of sunscreens on the US market found the average UVA protection factor was just 24% of the labeled SPF [6]. Bemotrizinol, marketed by BASF as Tinosorb S, covers the entire UVB and UVA range, with absorption peaks around 310 nm and 340 nm — the wavelengths most responsible for skin damage and premature aging [7].
Second, it keeps working in the sun rather than breaking down the way some older filters do. That photostability is bemotrizinol’s other advantage — it holds up in sunlight so well that it is used to stop other, flimsier filters from falling apart [8].
So unlike the minerals, it rubs in clear, holds up better in water, and covers the full range — the rare filter that pairs the stay-on-the-surface behaviour of a mineral with the feel and protection of a chemical. And it isn’t experimental: it has been used safely worldwide for about twenty-five years, with Europe approving it back in 1999 [9].
Which raises the obvious question. If it’s this good, and this old — why couldn’t Americans buy it until 2026?
Why America waited twenty years
The answer is not what you’d expect. In the United States, sunscreen is legally a drug. It goes back to a 1938 law — the logic being that sunscreen “prevents disease,” so it sits in the same regulatory bucket as medicine. To get a new drug ingredient approved requires clinical safety and effectiveness data, plus FDA clearance before it can be sold [10].
Everywhere else — Europe, Australia, Asia — sunscreen is a cosmetic, with a faster path: the company itself is responsible for showing its ingredient is safe, and can bring it to market without drug-style pre-approval [10]. That one difference — drug versus cosmetic — is the whole story.
And the cost of that difference is staggering. The United States went from 1999 all the way to 2026 — over a quarter of a century — without approving a single new sunscreen filter [11].
Bemotrizinol itself was first filed with the FDA back in 2005, and it wasn’t alone — it was one of a row of new filters that got submitted and then sat there. Eight other companies were in the same position, some pending for more than a decade with no decision either way [11].
By 2014 this had become enough of an embarrassment that Congress stepped in, passing the Sunscreen Innovation Act to force the FDA’s hand — review the backlog, hit hard deadlines, make a decision [11].
Here’s the twist. The law worked in the narrow sense that it forced the FDA to act — but the action it took, in 2016, was to lay out fresh requirements for sunscreen ingredient approval, requirements that meant lengthy clinical trials costing millions. A law built to speed things up produced a fresh round of “come back with more evidence.” As one industry figure put it: “Nobody did anything because it was way too expensive.” [11]
Three years later, in February 2019, the FDA issued an important update. Of all the sunscreen ingredients, only two — zinc oxide and titanium dioxide, the minerals — were recognized as both safe and effective. The twelve common chemical filters on the market all landed in a “we need more data” pile [12][2].
Then the FDA’s own scientists ran the absorption studies described earlier, where the older filters crossed that 0.5 ng/mL line. More data was now in hand — and instead of expanding the options on the market, it threatened to shrink them further.
One point of fairness about how those absorption tests were run, because it matters: they represented the worst-case scenario on purpose — sunscreen applied over 75% of the body, four times a day, for four days straight [2]. In everyday use, the amount reaching the blood is lower than those headline numbers. The point stands that it gets in — but that is a matter of not knowing the effects, which is very different from knowing there are actual harms.
So how did the logjam finally break? In 2020, buried inside the CARES Act — a pandemic relief law — Congress scrapped the slow old process for these over-the-counter products and replaced it with a faster one. Crucially, it added a reward: a company that does the expensive work of generating data for a brand-new filter gets a window of exclusivity to sell it. That provided both a faster route and a real reason to spend the money [11].
DSM-Firmenich, the company that makes bemotrizinol, took that deal — spending years and roughly $8 million generating exactly the data the FDA had been demanding, then paying the $537,000 filing fee on top [11]. That is what finally carried bemotrizinol across the line on June 9th, 2026. It doesn’t take effect until August 9th, though: the ingredient is cleared and products are coming, but in the US they won’t be on shelves until summer is almost over [13].
So what about in the meantime? Anyone who specifically wants to avoid filters that reach the bloodstream already has an option on the shelf today: the minerals, zinc oxide and titanium dioxide. They stay on the surface. The trade-off is the white cast they can leave, which is more noticeable on deeper skin tones.
The broader routine is straightforward: sunscreen every morning, and retinoid creams at night. Retinoids also strengthen the skin’s protective barrier, reduce water loss, and slow the enzymes that break down the skin’s support structure.
The oldest and most widely studied is tretinoin. First used to treat acne, it was soon noticed to improve the appearance of skin in general — including the signs of aging — and was approved by the FDA for that purpose. One large review of 180 individual studies reported that topical tretinoin improved the signs of photoaging — wrinkling, uneven coloration, and age spots — in as little as one month of use [14].
Tretinoin works well, but some people are sensitive to it — irritation, redness, and dryness, especially at first. That drawback led to newer, third-generation retinoids like adapalene, which cause less irritation. Does that mean sacrificing effectiveness? A 2018 head-to-head trial tested exactly that and concluded adapalene 0.3% gel was non-inferior to tretinoin 0.05% cream for photoaged skin, with a similar safety profile [15].
Alongside sunscreen in the morning, retinoids at night, a good diet, regular exercise, and high-quality sleep, two supplements have shown promise in human clinical trials.
The first is hyaluronic acid — the molecule skin uses to hold onto water, and which declines with age. In a randomised, placebo-controlled trial, people taking 200 mg a day of oral hyaluronic acid showed measurably better skin hydration (+10.6%) along with shallower wrinkles (depth −18.8%, volume −17.6%) and a small increase in elasticity and firmness over 28 days [16].
From the MicroVitamin range
MicroVitamin includes 200 mg of hyaluronic acid per daily serving, alongside 24 other evidence-based vitamins, minerals and ingredients in one daily formula.
The second is collagen. A 2023 meta-analysis pooled 26 randomized controlled trials, involving 1,721 people, of collagen peptide supplements and found they significantly improved skin hydration and elasticity compared with placebo [17].
From the MicroVitamin range
MicroVitamin+ Powder contains collagen peptides as part of its daily blend, combined with creatine, taurine and fibre in a single scoop.
Even with sunscreen worn faithfully since childhood, a certain amount of skin aging is inevitable. But there are more ways to counter it than ever before — many of them cheap, or even free.
References
1. https://onlinelibrary.wiley.com/doi/10.1111/phpp.12439
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6549296/
3. https://pubchem.ncbi.nlm.nih.gov/compound/Bemotrizinol
4. https://pubchem.ncbi.nlm.nih.gov/compound/4632
5. https://onlinelibrary.wiley.com/doi/10.1034/j.1600-0625.2000.009003165.x
6. https://onlinelibrary.wiley.com/doi/10.1111/phpp.12738
7. https://www.basf.com/us/en/media/news-releases/2026/06/P-US-26-27
8. https://pubmed.ncbi.nlm.nih.gov/11594052/
11. https://beautymatter.com/articles/the-great-sunscreen-odyssey
12. https://www.govinfo.gov/content/pkg/FR-2019-02-26/pdf/2019-03019.pdf
14. https://pmc.ncbi.nlm.nih.gov/articles/PMC9112391/
15. https://pubmed.ncbi.nlm.nih.gov/30105991/
