Hydrogenated Soybean Oil

Hydrogenated Soybean Oil is soybean oil (Glycine soja) that has been chemically treated with hydrogen gas to convert it's naturally unsaturated fats into saturated ones.

This turns a liquid oil into a more stable, semi-solid, waxy substance.

In formulas, it acts as a skin conditioning agent, emollient, and humectant that helps slow moisture loss from skin.

The Cosmetic Ingredient Review (CIR) Expert Panel has evaluated it and concluded it safe as used in cosmetics, citing low systemic toxicity, a long history of safe use, and low irritation/sensitization potential.

There's no mandatory maximum-use concentration and concentrations range from low single digits to 100%.

Soy is a common food allergen but cosmetic-grade Hydrogenated Soybean Oil is heavily refined. This means the proteins responsible for most soy allergic reactions are largely removed during that processing.

However, people with a known soy allergy should still patch test before use since trace protein residues can vary by manufacturing source.

Pore clogger

Regular soybean oil (the non-hydrogenated version) has been rated as moderately comedogenic on the Fulton rabbit-ear scale; this rabbit-ear model is increasingly seen as a poor predictor of real-world human pore-clogging since it uses undiluted ingredients on rabbit ear skin rather than realistic concentrations on human skin.

Later studies also revealed inconsistent results when the rabbit ear model was applied to human skin.

This ingredient shows up on a lot of "pore-clogging" lists but there's no real evidence behind that. It doesn't even have a comedogenic rating from an actual study; the numbers you'll find online come from blogs citing other blogs.

Some people still find it breaks them out. So if that's you, definitely trust your skin.

Fungal acne

Because this ingredient is a saturated triglyceride, it may not be fungal acne safe. This is because Malassezia breaks down sebum triglycerides into fatty acids it can consume, making this ingredient a possible source for the yeast.