Sd Alcohol 40-B
INCI: SD ALCOHOL 40-B
Reviewed by Kate · Last updated 2 Jun 2026
Also known as: Sd Alcohol 40-b
A volatile alcohol used as a solvent and astringent in skincare formulations
Best For Skin Types
Oily, Combination
Addresses
Effective Concentrations
10-70%
Usage Frequency
As tolerated
What Is Sd Alcohol 40-B?
SD Alcohol 40-B is a denatured ethanol classified as a solvent and viscosity-controlling agent in cosmetic formulations. It is volatile, meaning it evaporates quickly from the skin, and is commonly used to dissolve other ingredients, adjust product texture, or create lightweight formulations.
The "SD" designation indicates the alcohol has been denatured (rendered undrinkable) according to US regulations. It appears in roughly 0.2% of skincare products, typically at concentrations between 10% and 70%, depending on the product type and intended effect.
How It Works
SD Alcohol 40-B works primarily through evaporation and its ability to dissolve hydrophobic (oil-based) ingredients. When applied to skin, it evaporates rapidly, which can create a mild astringent or tightening sensation by temporarily drawing moisture from the surface.
As a solvent, it allows oil-soluble actives and botanical extracts to remain stable and bioavailable in a water-based formula. This function is particularly useful in alcohol-based toners, essences, and serums where ingredient solubility would otherwise be problematic.
Clinical Evidence & References
Evidence on SD Alcohol 40-B's astringent effects on skin is largely empirical rather than derived from robust clinical trials. Some research suggests that volatile alcohols can produce a transient tightening sensation, though this is superficial and does not represent lasting structural change.
Limited formal studies exist on safety and efficacy at cosmetic-use concentrations. However, it is generally regarded as safe in skincare products at typical usage levels, with the main concern being potential dryness or irritation in sensitive individuals, particularly at higher concentrations.
How to Use
Products containing SD Alcohol 40-B are typically applied as directed on the label—usually daily as part of a toner, essence, or targeted serum. Allow the product to dry completely before applying other formulations. If you have dry or sensitive skin, patch-test first and consider using such products only a few times per week or alternating with hydrating formulations to avoid over-drying the skin barrier.
Safety & Precautions
Frequently Asked Questions
From the Clinic
Not sure what your skin actually needs?
Two minutes, a few questions, and we’ll point you at what matters — no guesswork.
Take the skin quizRelated Ingredients
Rhus Succedanea Fruit Wax
A plant-derived wax that stabilises texture and consistency in skincare formulations
Ricinoleic Acid …
A polymer that stabilises texture and controls viscosity in skincare formulations
Sclerotium Gum
A naturally derived, sugar-based ingredient | Produced by the fermentation of the Sclerotium rolfsii fungus
Shea Butteramide/Castoramide DEA
A viscosity regulator derived from natural plant oils, used to control product texture
Silica
Natural ingredient found in clays as well as in parts of plants and animals | Used as an absorbent powder and thickener in cosmetics
Silica Dimethyl Silylate
Synthetic ingredient used as a slip and suspending agent in cosmetics
Learn More About Skincare Ingredients
Explore our comprehensive ingredient glossary to understand what's in your products.
Browse All IngredientsShop Our Products
Find professional skincare solutions at Skintique.