What Is Alcohol Denat. Sd Alcohol 39-C?
Alcohol Denat. Sd Alcohol 39-C is a form of ethyl alcohol that has been denatured with a small amount of diethyl phthalate to make it unfit for drinking, which allows manufacturers to avoid beverage taxes and regulatory hurdles. Chemically, it is the same ethanol found in spirits or fuel, but the added denaturant changes its taste and odor so it is used strictly for industrial and cosmetic purposes. Ethanol has been part of personal care formulas since the early 1900s because it evaporates quickly, dissolves many ingredients and leaves a clean finish on skin or hair. The “39-C” code indicates it meets a specific United States federal standard (27 CFR 21) that defines the precise ratio of ethanol to diethyl phthalate.
Production begins with the fermentation of plant sugars, usually from corn or sugarcane, which yields crude ethanol. The liquid is then distilled to high purity, after which a tiny percentage of diethyl phthalate is blended in to create the denatured version. This mixture is filtered and quality checked before being shipped to cosmetics manufacturers worldwide.
Thanks to its clarity, low viscosity and fast drying nature, Alcohol Denat. Sd Alcohol 39-C appears in a wide range of beauty products. You are most likely to see it in facial toners, setting sprays, perfumes, hair styling sprays, hand sanitizers, quick-dry nail treatments, lightweight facial gels and some oil-control lotions. It can also be used in high-performance serums where formulators need to keep water and oil phases stable or where a weightless skin feel is desired.
Alcohol Denat. Sd Alcohol 39-C’s Cosmetic Benefits/Uses
In cosmetic formulas Alcohol Denat. Sd Alcohol 39-C plays a single yet crucial role.
As a solvent it dissolves active ingredients, fragrances and film formers so they blend evenly and remain stable in the finished product. This ensures that sprays mist out evenly, gels stay clear, lotions feel light and fragrances last longer after application. Its rapid evaporation also helps products dry quickly without leaving residue which can enhance user comfort and reduce the need for heavier preservatives.
Who Can Use Alcohol Denat. Sd Alcohol 39-C
Because Alcohol Denat. Sd Alcohol 39-C evaporates fast and leaves no oily film it is generally suitable for oily, combination and acne prone skin that appreciates a lightweight feel. Normal skin usually tolerates it well too. Those with very dry, mature or sensitive skin may find high levels of this alcohol overly stripping because it can pull water from the surface and disturb the skin’s protective barrier, which may lead to tightness or flaking.
The ingredient is plant derived in most modern supply chains and contains no animal by-products, so it is considered vegan and vegetarian friendly. Its production does not rely on animal testing in regions that have banned the practice, though finished products can vary by brand policy.
Pregnant or breastfeeding women are not known to face extra risks from topical use because systemic absorption of ethanol in cosmetics is minimal. That said this is not medical advice and anyone expecting or nursing should ask a healthcare provider before adding new skincare or fragrance products.
Alcohol Denat. Sd Alcohol 39-C is not photoreactive and does not increase sun sensitivity. It also does not interfere with common actives like vitamin C, niacinamide or retinoids, although very high alcohol content might cause faster evaporation of some water-based formulas.
Potential Side Effects/Adverse Reactions
Reactions to Alcohol Denat. Sd Alcohol 39-C vary from person to person. The points below list potential side effects, but most users will not experience them when the ingredient is used at typical cosmetic levels.
- Dryness or tight sensation: the solvent can draw moisture from the outer layer of skin especially in low humidity
- Stinging or burning: freshly exfoliated, compromised or highly sensitive skin may feel a brief sting on contact
- Flaking or rough texture: repeated use in high concentrations might weaken the lipid barrier leading to visible flaking
- Redness or irritation: a small number of individuals may develop erythema or mild inflammation after application
- Contact dermatitis: rare allergy to ethanol or the denaturant diethyl phthalate can trigger itching or rash
If you notice persistent irritation, discontinue use and seek advice from a medical professional or dermatologist.
Comedogenic Rating
Comedogenic rating: 0/5. Alcohol Denat. Sd Alcohol 39-C is a volatile solvent that flashes off skin within seconds, so it never lingers long enough to mix with sebum or block pores. It contains no oils or waxes and leaves zero residue, making it generally suitable for people who struggle with acne or frequent breakouts.
Because it evaporates so quickly there is virtually no chance of buildup, although products that pair high alcohol levels with heavy emollients could still clog pores from those other ingredients, not from the alcohol itself.
Summary
Alcohol Denat. Sd Alcohol 39-C works primarily as a solvent, dissolving actives, fragrances and film formers then evaporating to deliver a light, fast drying feel. This quick flash off keeps formulas clear, helps sprays mist evenly and lets products set in seconds.
Its reliability, affordability and plant based sourcing have kept it popular in toners, perfumes, hair sprays, setting mists and hand sanitizers, though a growing number of brands now offer lower alcohol alternatives for very sensitive skin.
Regulatory bodies consider it safe at cosmetic levels with irritation or dryness being the main concerns at high concentrations. Still, patch test any new product to be sure your skin is comfortable with the complete formula.