What Is Alcohol Denat. Sd Alcohol 39-B?
Alcohol Denat. Sd Alcohol 39-B is a form of ethyl alcohol that has been denatured with small amounts of t-butyl alcohol and diethyl phthalate, a process that makes it unfit for drinking while keeping its useful properties for cosmetics. Ethyl alcohol itself is usually obtained by fermenting plant sugars found in corn, sugarcane or grain. Once distilled to a high purity it is blended with the denaturants according to the U.S. regulation 27 CFR 21, creating the final Sd Alcohol 39-B grade.
Denatured alcohol has been part of personal care formulas since the early 1900s when manufacturers sought a fast-evaporating carrier that avoided the taxes placed on potable alcohol. The specific 39-B variant became popular with perfume and skincare makers because it balances quick dry-down with a relatively mild odor.
Production is straightforward: purified ethanol is pumped into stainless steel tanks, precise doses of t-butyl alcohol and diethyl phthalate are added, then the blend is mixed and tested to confirm the correct denaturing ratio before being filled into drums for cosmetic labs.
You will most often see Alcohol Denat. Sd Alcohol 39-B in products that benefit from a light skin feel or require quick setting such as fine fragrances, body sprays, toners, makeup setting mists, hair styling sprays, hand sanitizers and certain gel creams.
Alcohol Denat. Sd Alcohol 39-B’s Cosmetic Benefits/Uses
In cosmetic formulas this ingredient serves one main role that brings several practical advantages.
As a solvent it dissolves fragrance oils, plant extracts and film formers so they can be evenly distributed in a water-based product. Because it flashes off rapidly after application it leaves behind the active ingredients without a heavy or greasy residue, giving products a lightweight feel and helping them dry quickly on the skin or hair.
Who Can Use Alcohol Denat. Sd Alcohol 39-B
This fast evaporating alcohol suits normal and oily skin best because it leaves no residue and helps products feel weightless. People with combination skin usually tolerate it well in low to moderate amounts. Those with very dry or sensitive skin may find that frequent exposure increases moisture loss or stinging so they may prefer formulas that place it lower on the ingredient list or avoid it altogether.
SD Alcohol 39-B is made from plant based ethanol and does not rely on any animal derived components, making it acceptable for vegans and vegetarians as long as the finished product also stays free of animal ingredients.
The ingredient is considered safe for use during pregnancy and breastfeeding when applied as directed in cosmetics because it evaporates quickly and has minimal skin absorption. This is not medical advice and expecting or nursing mothers should check with their doctor before adding any new personal care product.
It does not increase photosensitivity, so it will not make skin burn faster in the sun. Because it is highly flammable, keep products containing it away from open flames and high heat.
Potential Side Effects/Adverse Reactions
Responses to topical Alcohol Denat. Sd Alcohol 39-B differ from person to person. The points below list possible side effects but most users will not encounter them when the ingredient is used correctly in a well formulated product.
- Skin dryness – rapid evaporation can pull water from the surface leaving skin feeling tight or flaky, especially with repeated use
- Stinging or burning – freshly exfoliated, broken or very sensitive skin can tingle or burn on contact
- Redness and irritation – higher concentrations may disrupt the protective barrier leading to temporary redness or itch
- Contact dermatitis – in rare cases users may react to the alcohol itself or to the denaturants resulting in a rash
- Exacerbation of existing skin conditions – conditions like eczema or rosacea can flare when exposed to strong alcohol
- Eye and mucous membrane irritation – vapors or accidental splashes can irritate the eyes, nose or mouth
If any of these effects occur stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 0 / 5
Alcohol Denat. Sd Alcohol 39-B is a light volatile liquid that evaporates almost as soon as it is applied, so it does not sit on the skin or mix with sebum in a way that could block pores. Because it leaves no film and contains no fatty acids or oils it is considered non-comedogenic.
That means it is generally suitable for people who are prone to acne or breakouts, though very drying formulas could prompt some skins to overproduce oil which may indirectly contribute to congestion.
Summary
Alcohol Denat. Sd Alcohol 39-B acts mainly as a solvent, carrying fragrance, botanical extracts and film formers into a water-based system then flashing off to leave a light feel and quick dry finish. Its speed of evaporation also helps stabilize sprays and mists by keeping the mixture uniform until it exits the nozzle.
The ingredient is popular in perfumes, body sprays, makeup setting mists, toners and hand sanitizers because it delivers a clean skin feel and speeds up dry time. While some brands are shifting toward lower alcohol levels to cater to sensitive and dry skin types, Sd Alcohol 39-B remains a staple in many fast-drying formulas.
Regulatory bodies worldwide consider it safe in the concentrations found in cosmetics. Side effects are mainly limited to dryness or irritation in sensitive users. As with any new product it is wise to perform a small patch test to confirm personal tolerance.