Dermalogica Deep Acne Invisible Liquid Patch Versus Murad Rapid Relief Acne Sulfur Mask

Though it can't kill microbes on its own, it works as a good supporting agent when combined with other preservatives like Phenoxyethanol or 1,2-Hexanediol.

This ingredient naturally occurs as piceol in Norwegian spruce needles (~0.4-1.1% dry weight and in cloudberries). Though the cosmetic-grade material is synthesized for purity and consistency.

You'll usually see it used at low levels and suppliers recommend up to 1% added to a water phase.

Safety testing was done at concentrations like 0.05% in SPF products and 0.5% in a Human Repeated Insult Patch Test. The safety evidence is assuring; this ingredient is safe for cosmetics in current use and also holds safety status as a food flavoring as well.

An honest caveat: the "soothing" and "anti-inflammatory" claims come mostly from supplier marketing rather than published clinical trials. The Cosmetic Ingredient Review's own literature search found no useful efficacy studies on this ingredient.

So the antioxidant and preservative-boosting roles are the well supported ones while the calming benefit is plausible but thinly evidenced.

Overall, this is a well-tolerated, low-irritation multitasker that quietly helps a formula stay fresh and stable.

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

When sulfur touches skin, it reacts with an amino acid in skin cells (called cysteine) to create cystine and hydrogen sulfide.

That hydrogen sulfide helps loosen dead skin cells to exfoliate. And here's a geeky detail: the smaller the Sulfur particles, the more they interact with skin and the better they work.

Sulfur also has antifungal and antibacterial activity, which is why you'll see it in both acne treatments and dandruff shampoos.

In the US, acne products can use 3-10% sulfur while dandruff products use 2-5%. It's also often paired with Sodium Sulfacetamide, and using that combo twice daily for 12 weeks reduced inflammatory acne spots by about 80%.

The most common complains are the smell and dryness. Otherwise, side effects are uncommon.

If you have a "sulfa" allergy, that's an allergy to sulfonamide drugs and this doesn't mean you'll react to elemental sulfur.

A 1972 study suggested sulfur might clog pores. Elemental sulfur caused some clogged pores on rabbit ears and human backs (though the researchers noted the effect was mild).

A 1978 follow-up tested this on 52 people. After six weeks of patches with 5% Sulfur, skin biopsies showed no link between Sulfur and clogged pores. The surprise? The base the Sulfur was mixed into was what caused clogged pores. Later reviewers also noted that other studies couldn't repeat the 1972 results.

So why does Sulfur have a comedogenic rating of 3?

That number comes from a 1989 rabbit ear study by dermatologist James Fulton, which gave a 3 to water-soluble sulfur specifically. Even so, a 3 isn't a big red flag. Fulton's own scale treats 2 to 3 as borderline.

Human testing has also proved that any finished product with a comedogenic ingredient won't automatically make you break out; it really comes down to concentration, formula, and your skin.

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!