Ingredient review
SD Alcohol 27-B
INCI: SD Alcohol 27-B
SD Alcohol 27-B is a fast-evaporating solvent that can help products feel lightweight but may be drying or irritating for sensitive skin.
In plain English
SD Alcohol 27-B is a type of denatured alcohol, meaning ethanol that has been treated with additives to make it undrinkable. In skincare, it's used to help ingredients dissolve, make products dry quickly, and give a matte finish. However, it can strip the skin's natural oils and disrupt the moisture barrier if used too often or in high amounts.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is relatively strong for its common cosmetic role.
Main practical flags: irritation is high; clogging risk is low.
- Source
- synthetic
- Evidence
- strong
- Irritation
- high
- Clogging risk
- low
Quick decision guide
Useful, but context matters
SD Alcohol 27-B can be useful, but watch for high irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging SD Alcohol 27-B.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
highMore likely to cause dryness, stinging, peeling, or reactivity if used too aggressively.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
strongThere is a stronger practical or research basis for the ingredient role described here.
What it is
SD Alcohol 27-B is a denatured alcohol, specifically ethanol modified with denaturants to prevent consumption. It is a clear, volatile liquid that evaporates rapidly.
How it works
It acts as a solvent to dissolve other ingredients and as a quick-drying agent. When applied to skin, it evaporates quickly, creating a cooling sensation and temporarily tightening pores. It also has antimicrobial properties that can help reduce acne-causing bacteria.
Pros
Quick-drying
Evaporates fast, making products feel lightweight and non-sticky, ideal for oily skin types.
Antimicrobial
Helps reduce bacteria on the skin, which can be beneficial for acne-prone individuals.
Cons and cautions
Drying
Can strip natural oils, leading to dryness and irritation, especially with frequent use.
Barrier disruption
Overuse may weaken the skin's moisture barrier, causing increased sensitivity and redness.
Best for
- People with oily or acne-prone skin looking for quick-drying formulas
- Those who tolerate alcohol well and want a lightweight texture
Use caution if
- People with dry, sensitive, or compromised skin barriers
- Those with rosacea or eczema
Usage tips
Safety summary
Generally safe in low concentrations for short-term use, but high or frequent exposure can cause skin irritation and dryness. Avoid on broken or irritated skin.
Research notes
Studies confirm that denatured alcohol can disrupt the skin barrier and increase transepidermal water loss (TEWL), especially in sensitive skin. However, it remains effective as a solvent and antimicrobial in controlled amounts.
Common label clues
- Typical concentration
- Usually 1% to 50% depending on product type
- Regulatory status
- Approved for cosmetic use in the US and EU, with restrictions on denaturant types and concentrations.
- Common uses
- Toners, Cleansers, Acne treatments, Sunscreens
- Environmental note
- Produced from fermentation of crops like corn or sugarcane; volatile organic compound (VOC) emissions are a concern in large-scale manufacturing.
Good to know
- SD Alcohol 27-B is often listed as Alcohol Denat. on labels
- It is different from fatty alcohols (like cetyl alcohol) which are moisturizing
Common questions
What is SD Alcohol 27-B in beauty products?
SD Alcohol 27-B is a type of denatured alcohol, meaning ethanol that has been treated with additives to make it undrinkable. In skincare, it's used to help ingredients dissolve, make products dry quickly, and give a matte finish. However, it can strip the skin's natural oils and disrupt the moisture barrier if used too often or in high amounts.
What does SD Alcohol 27-B do in a beauty product?
It acts as a solvent to dissolve other ingredients and as a quick-drying agent. When applied to skin, it evaporates quickly, creating a cooling sensation and temporarily tightening pores. It also has antimicrobial properties that can help reduce acne-causing bacteria.
Is SD Alcohol 27-B safe for most people?
Generally safe in low concentrations for short-term use, but high or frequent exposure can cause skin irritation and dryness. Avoid on broken or irritated skin.
Who should be careful with SD Alcohol 27-B?
People with dry, sensitive, or compromised skin barriers Those with rosacea or eczema
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.