Colloidal Sulfur

Colloidal sulfur is a skin care ingredient that's often used in products for its anti-acne properties. It differs from traditional sulfur in that it's engineered to have much smaller particles, boosting the potency of this over-the-counter active. It is sometimes also referred to as sulfur nanoparticles. How colloidal sulfur works for acne is multifactorial. It is a mild keratolytic, meaning it causes dead cells on skin's surface to shed (i.e., exfoliate). Sulfur's antibacterial properties help inhibit the over proliferation of acne-causing bacteria, and sulfur has some anti-inflammatory properties that can help fight irritating factors the lead to breakouts. New research is also underway to see if nano-sized sulfur particles (colloidal sulfur) might be an alternative to combat strains of acne-causing bacteria that are becoming resistant to traditional antibiotic therapies.

Topical application of sulfur and colloidal sulfur can cause some mild sensitization, though extreme adverse events are considered rare. According to suppliers, colloidal sulfur is effective for anti-acne purposes at 3-10%, the same range it gained FDA approval for use in over-the-counter acne products. Outside of skin care, sulfur and colloidal sulfur are commonly used in hair care products to combat dandruff. For these purposes, colloidal sulfur is most effective in amounts between 2% and 5%. Compared to traditional preparations of sulfur, the colloidal form dissolves much more readily in water and is a finely milled pale, yellow powder in its raw material state. It's also much less likely to have a perceivable "rotten egg" odor than regular (precipitated) sulfur since the smaller particle size of the colloidal form minimizes the volatility that leads to this undesirable scent.

*Note: In the past, we've raised concerns about sulfur and its derivatives because of their tendency to be harsh and drying. Today, thanks to evolving research and ingredient technologies, we know much more about how to use this ingredient effectively. When formulated within its recommended range, sulfur can play a valuable role in addressing certain skin concerns—especially acne—by helping reduce breakouts, calm redness and inflammation, and promote smoother skin. What about the issue of sulfur's pH being too alkaline for skin? As it turns out, sulfur can be formulated in a wide pH range without losing its efficacy or impacting product stability. We know much more know about which buffers and stabilizers are necessary to ensure sulfur doesn't creep into the skin-damaging alkaline pH range. As always with skin care, it comes down to the total formula and technologies behind it rather than a single ingredient.*