Naturally Derived, and Only Five: How Swellies Built a Sunscreen From Minerals and Plants

We did not set out to make a "natural" sunscreen. We set out to make one where every ingredient earns its place. What we ended up with is five ingredients, and all five happen to be naturally derived, from minerals and plants. That is a byproduct of picking the right tools for the job, not a marketing goal. The difference matters, so let us be clear about it.

"Naturally derived" is not a safety claim

Natural does not automatically mean safe, and synthetic does not automatically mean risky. Poison ivy is natural. Purified water is synthesized. The question that matters for a sunscreen is whether an ingredient works, whether it is well studied, and whether it needs to be there at all. We judged our formula on that, not on how wholesome the ingredients sound. It turned out the five that passed were all mineral or plant derived. Good. But the derivation is the result, not the reason.

Two of the five are minerals

• Zinc Oxide (non-nano), 21%. A mineral, and the only active. It covers the full UVA and UVB range on its own and sits on the surface of the skin rather than absorbing. Non-nano means the particles are large enough that they stay on top of your skin.
• Iron Oxides. Mineral pigments. A sheer tint that cancels the white cast zinc would otherwise leave, and blocks high-energy visible light as a bonus.

Three of the five come from plants

The other three are esters and derivatives sourced from plants, and each one has a specific job in turning a chalky mineral paste into something you will actually wear:

• Coco Caprylate/Caprate. A lightweight ester derived from coconut. It is the carrier, the thing the zinc is suspended in, and it is why the formula feels light instead of greasy. It replaces the silicones most sunscreens lean on.
• Dextrin Palmitate. Built from a plant starch (dextrin) and a plant fatty acid. It turns the formula into a breathable gel and controls the finish.
• Polyhydroxystearic Acid. Derived from castor oil. It disperses the zinc evenly so it lays down smooth, which is half the reason there is no white cast.

How five was even possible

Most sunscreens are long because they are anchored in water. Add water and you need emulsifiers to bind it to the oils, preservatives to keep it from growing bacteria, and stabilizers to hold it all together. Swellies is anhydrous, meaning water-free. No water means no preservative system, no emulsifier stack, none of the ingredients that exist only to manage water. Take water out and the list gets short on its own. We wrote the full case for that here: 5 ingredients vs. 30.

So the list reads: two minerals, three plant-derived esters. No fragrance, no preservatives, no silicones, no seed oils, no water, no fillers. Broad spectrum SPF 46, water resistant 40 minutes.

An outside opinion

We are not the only ones who read the list this way. The Yuka app, which scores products on their ingredients independently, rates Swellies 93 out of 100, "Excellent," with four of the five ingredients marked risk-free and zinc oxide, the active, marked low risk. We did not build the formula for a score. But a short, naturally derived list tends to read well when someone checks.

Frequently asked questions

Is Swellies a natural sunscreen?

All five of its ingredients are naturally derived, from minerals and plants. That said, we do not lead with "natural," because natural on its own is not a measure of whether something is safe or effective. We chose each ingredient because it does a specific job, and the five that made the cut happen to be mineral or plant derived.

What are the five ingredients in Swellies?

Non-nano zinc oxide (the only active), iron oxides, coco caprylate/caprate, dextrin palmitate, and polyhydroxystearic acid. Two minerals and three plant-derived esters. No fragrance, preservatives, silicones, seed oils, or water.

How can a sunscreen have only five ingredients?

Most of the length in a sunscreen comes from being water-based, which requires preservatives, emulsifiers, and stabilizers. Swellies is anhydrous, so it needs none of those. Removing water removes the reason for most of the extra ingredients.

Is naturally derived better than synthetic?

Not automatically. Some naturally derived ingredients are excellent and some are irritating; the same is true of synthetic ones. What matters is whether an ingredient is well studied, does its job, and needs to be in the formula. Swellies is naturally derived because those ingredients met that bar, not the other way around.

Two minerals, three from plants, five in total. See Swellies →