What Is Sd Alcohol 39-B?
Sd Alcohol 39-B is a form of denatured ethyl alcohol that has been rendered undrinkable by adding a small amount of tert-butyl alcohol along with a bittering agent. The base ethanol is typically produced by fermenting and distilling plant sugars from corn, wheat or sugarcane, yielding a clear, highly volatile liquid. Manufacturers then mix in the approved denaturants to comply with regulations that exempt the alcohol from beverage taxes, making it economical for cosmetic use.
Alcohol has featured in beauty routines since the early 1900s for its quick-drying feel and refreshing skin effect. The specific Sd Alcohol 39-B designation appeared as industry and regulators refined denaturing formulas to balance performance, safety and cost. Today the ingredient is made in large-scale distilleries, filtered to high purity then blended with the precise denaturant ratio before shipment to cosmetic labs.
You will most often see Sd Alcohol 39-B in lightweight products where fast evaporation and a clean skin finish are desirable. Common examples include facial toners, makeup setting sprays, oil-controlling lotions, fragrance mists, quick-dry hair sprays, gel textures and certain clay or peel-off masks.
Sd Alcohol 39-B’s Cosmetic Benefits/Uses
In a formula Sd Alcohol 39-B serves more than one technical role that ultimately shapes how the product feels and performs.
- Astringent: Helps tighten the look of pores and gives skin a refreshed sensation which can be especially useful in toners aimed at oily or combination skin
- Solvent: Efficiently dissolves fragrance oils, botanical extracts and film-forming polymers allowing for clear stable solutions that spray or spread evenly
- Viscosity Controlling: Thins heavy mixtures so they feel lightweight and absorb quickly improving user experience in quick-dry sprays gels or lotions
Who Can Use Sd Alcohol 39-B
Sd Alcohol 39-B is generally best suited to normal, oily or combination skin because its quick evaporation and astringent action help cut excess surface oil and leave a fresh finish. Very dry or easily irritated skin may find it too stripping, especially in high-alcohol toners or sprays, as the ingredient can pull water from the surface and weaken an already fragile barrier.
The ethanol used to make Sd Alcohol 39-B is sourced from plant fermentation and the added denaturants are synthetic so the ingredient is considered suitable for vegans and vegetarians.
Topical use during pregnancy or while breastfeeding is widely viewed as low risk because the alcohol evaporates almost instantly and very little is absorbed through intact skin. This is not medical advice and anyone who is pregnant or nursing should still check any skincare product with a healthcare professional to be safe.
Sd Alcohol 39-B does not make skin more sensitive to sunlight and will not lower the effectiveness of sunscreen. Because it is highly flammable it should be kept away from open flame and high heat when applying products like hair sprays or body mists.
Potential Side Effects/Adverse Reactions
Reactions to topical Sd Alcohol 39-B vary between individuals. The points below list potential but uncommon side effects when the ingredient is used in a well-formulated product.
- Dryness and tightness especially on already dry or compromised skin
- Redness or stinging on sensitive or freshly exfoliated skin
- Flare-ups of conditions such as eczema or rosacea if the barrier is disrupted
- Contact dermatitis in rare cases of sensitivity to ethanol or the denaturant
- Eye irritation or watering when sprayed too close to the eyes
- Nasal or throat discomfort from inhaling fine mist in poorly ventilated spaces
If any of these reactions occur stop using the product and consult a healthcare professional
Comedogenic Rating
Rating: 0/5
Sd Alcohol 39-B is a volatile alcohol that evaporates almost as soon as it is spread on the skin, leaving little to no residue that could clog pores. Because it does not sit on the surface or mix with skin oils for long, it is considered non-comedogenic. People who are prone to acne or breakouts usually tolerate it well, provided the rest of the formula is also low in pore-clogging ingredients. The main caution is dryness; dehydrated skin can overproduce oil in response, which might indirectly lead to congestion, but the alcohol itself is not the culprit.
Its rapid evaporation also means it will not interfere with leave-on actives that target blemishes, so it often appears in acne-focused toners or sprays to create a weightless finish.
Summary
Sd Alcohol 39-B works as an astringent, solvent and viscosity controller. It tightens the feel of pores, dissolves oils and actives so they stay evenly mixed, and thins thick formulas so they spread fast then dry down with no tacky after-feel. Thanks to these properties it shows up in toners, setting sprays, hair sprays and quick-dry gels.
The ingredient is popular in products that need a light, refreshing touch, though brands aimed at very dry or sensitive skin often skip it in favor of gentler humectants. Overall safety is high when used as directed because it evaporates quickly and has a long history of cosmetic use. Still, skin types differ, so performing a small patch test whenever you try a new product with Sd Alcohol 39-B is the best way to make sure it suits you.