What Is Sd Alcohol 37?
Sd Alcohol 37, often labeled on ingredient lists as Alcohol Denat., is a specially denatured form of ethyl alcohol. Ethyl alcohol itself is derived from the fermentation of plant sugars, commonly from corn, sugarcane or grain. To make it unsuitable for drinking, manufacturers add a small amount of denaturant, which gives the alcohol its Sd, or “specially denatured,” designation. This keeps it tax exempt for industrial and cosmetic use while preventing misuse.
The use of denatured alcohol in beauty products dates back to the early 20th century when formulators sought quick-drying solvents for hair sprays and fragrances. Over time Sd Alcohol 37 became a popular option thanks to its reliable purity level, consistent evaporation rate and compatibility with many other cosmetic ingredients. Production involves fermenting a plant source to create ethanol, distilling it for high purity then adding the approved denaturant before final filtration and quality checks.
You are most likely to see Sd Alcohol 37 in products where a lightweight finish and fast dry time are important. Typical examples include facial toners, setting sprays, hair sprays, liquid or cream foundations, aftershave lotions, spot treatments for oily skin, quick-dry top coats for nails and certain peel-off masks. Its ability to dissolve oils and resins while evaporating swiftly makes it attractive to formulators who want a product that feels fresh rather than sticky.
Sd Alcohol 37’s Cosmetic Benefits/Uses
Below are the key roles Sd Alcohol 37 plays in personal care formulas and the advantages each role provides.
- Astringent: Helps tighten the appearance of pores and gives an instant refreshing feel, making oily or combination skin products feel lighter and cleaner.
- Solvent: Efficiently dissolves oils, resins and other active ingredients so they distribute evenly, which ensures clear, uniform sprays, gels and liquids.
- Viscosity Controlling: Thins down thicker mixtures to achieve a desired light texture, improving spreadability and keeping formulas from feeling heavy on the skin or hair.
Who Can Use Sd Alcohol 37
Sd Alcohol 37 works best for oily and combination skin types because it quickly whisks away excess surface oil and leaves a weightless finish. Normal skin usually tolerates it well in leave-on or rinse-off formulas. Very dry or sensitive skin may find frequent use too stripping since the ingredient can pull moisture from the upper layers, which might worsen flakiness or redness.
The alcohol is produced from plant-based fermentation and no animal-derived additives are used, so products formulated with it are generally suitable for both vegetarians and vegans. Brands may still differ in overall animal-testing policies, so shoppers who follow a strict cruelty-free lifestyle should look for the appropriate certification on the finished product.
Topical Sd Alcohol 37 has minimal skin absorption and is not suspected of being harmful to pregnant or breastfeeding women when used in normal cosmetic concentrations. This is not medical advice; anyone who is pregnant or nursing should always clear new skincare with a qualified health professional just to be safe.
The ingredient does not increase photosensitivity and will not make the skin more prone to sunburn. It also does not interfere with sunscreen filters, so daytime use is acceptable when paired with standard sun protection.
Potential Side Effects/Adverse Reactions
Responses to Sd Alcohol 37 vary between individuals. The points below cover potential side effects that could occur; most users will not experience these problems when the ingredient is used at appropriate levels in a well-formulated product.
- Dryness or tight feeling particularly for those with already dry or compromised skin
- Transient stinging or burning when applied to freshly shaved or broken skin
- Redness or irritation in people with reactive or sensitive complexions
- Flare-ups of eczema or rosacea if the condition is already present
- Contact dermatitis in the rare case of an individual allergy or intolerance
If any of these effects occur, stop using the product and seek guidance from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0/5
Sd Alcohol 37 evaporates almost instantly after application leaving no oily or waxy residue behind, so it does not sit on the skin long enough to block pores. Its molecular structure is small and highly volatile which means it disperses into the air rather than staying on the surface where comedogenic ingredients normally create problems.
Because of this quick-dry characteristic the ingredient is generally suitable for people who are prone to acne or breakouts.
Keep in mind that overall formula matters. If Sd Alcohol 37 is paired with heavier oils or butters the finished product’s clogging potential depends on those other ingredients, not the alcohol itself.
Summary
Sd Alcohol 37 functions primarily as an astringent, solvent and viscosity controller. It tightens the feel of skin by briefly removing surface water and oil, dissolves resins and actives so they distribute evenly and thins thicker mixtures to create lightweight sprays, gels or liquids that dry fast.
The ingredient is popular in setting sprays, toners, hair sprays and quick-dry cosmetics because consumers like formulas that feel weightless and finish quickly without stickiness. Some brands avoid it in products for very dry or sensitive skin since its oil-whisking action can be too strong for those users.
Overall safety is considered high when used at normal cosmetic levels. It has low skin penetration, breaks down rapidly and is not linked to long-term health concerns. As with any new skincare product you should perform a simple patch test before full use to ensure your skin is happy with the entire formula.