Ingredient review

SD Alcohol 37

INCI: SD ALCOHOL 37

SD Alcohol 37 helps products dry fast and feel clean, but can be drying and irritating for sensitive or dry skin.

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In plain English

SD Alcohol 37 is a type of alcohol that has been denatured (made unfit to drink) for use in cosmetics. It evaporates quickly, which helps products feel lightweight and dry fast, and it can kill bacteria on the skin. However, it can also strip the skin of its natural oils, leading to dryness, irritation, and a compromised skin barrier if used too often or in high amounts.

Review score

Safety, usefulness, and evidence

3.0Fair
3.0/ 5

Useful in the right context, but not low-maintenance

The evidence base is relatively strong for its common cosmetic role.

Main practical flags: irritation is moderate; clogging risk is low.

Source
synthetic
Evidence
strong
Irritation
moderate
Clogging risk
low
How reviews are scored

Quick decision guide

Read the cautions before using

SD Alcohol 37 can be useful, but watch for some irritation potential.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging SD Alcohol 37.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

moderate

Can bother some users, especially with frequent use, damaged skin, or strong companion ingredients.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

strong

There is a stronger practical or research basis for the ingredient role described here.

What it is

SD Alcohol 37 is denatured ethanol, meaning ethanol mixed with denaturants to make it unsuitable for consumption. It is a volatile solvent commonly used in skincare to dissolve other ingredients, create a quick-drying feel, and provide a mild antimicrobial effect.

How it works

When applied to the skin, SD Alcohol 37 evaporates rapidly, which can make the skin feel tight and clean. It also helps other ingredients penetrate more easily by temporarily disrupting the skin's barrier. Its antimicrobial properties can reduce surface bacteria, which is why it's often used in acne products.

Pros

Fast evaporation

SD Alcohol 37 dries quickly, making products feel light and non-greasy, which is ideal for oily skin types or hot climates.

Antimicrobial benefits

Its ability to kill surface bacteria can help reduce acne breakouts when used in targeted treatments.

Cons and cautions

Drying effect

Frequent use can strip the skin of its natural moisture barrier, leading to increased dryness, flakiness, and irritation over time.

Potential irritation

For sensitive or damaged skin, SD Alcohol 37 can cause stinging, redness, and worsen conditions like eczema or rosacea.

Best for

  • People with oily or acne-prone skin who tolerate alcohol well
  • Those looking for a quick-drying toner or spot treatment

Use caution if

  • People with dry, sensitive, or eczema-prone skin
  • Anyone with a compromised skin barrier or rosacea

Usage tips

Use only on oily or acne-prone areas, not all over the face if you have combination skin.
Follow with a moisturizer to replenish hydration after using an alcohol-based product.
Avoid using high-alcohol products more than once daily to prevent over-drying.

Safety summary

SD Alcohol 37 is generally safe for cosmetic use at typical concentrations, but it can cause dryness and irritation, especially for sensitive skin. The Cosmetic Ingredient Review (CIR) panel has deemed denatured alcohol safe when formulated properly, but caution is advised for frequent use on compromised skin.

Research notes

Research shows that denatured alcohol can disrupt the skin barrier and increase transepidermal water loss (TEWL) with repeated use. However, it is effective as a solvent and antimicrobial in controlled amounts. Studies support its use in acne treatments but recommend limiting exposure for dry or sensitive skin.

Common label clues

Typical concentration
Usually 1-10% in leave-on products; higher in rinse-off or quick-dry formulas
Regulatory status
Approved for use in cosmetics in the US and EU, with concentration limits in some regions. Denaturants must be approved by regulatory bodies.
Common uses
Toners, Astringents, Acne treatments, Fragrance
Environmental note
SD Alcohol 37 is produced synthetically from petrochemicals or fermented from grains. Its production has a moderate environmental footprint, but it is biodegradable.

Good to know

  • SD Alcohol 37 is often listed as 'Alcohol Denat.' on ingredient labels.
  • Not all alcohols in skincare are drying—fatty alcohols like cetyl alcohol are moisturizing.
  • The 'SD' stands for 'specially denatured,' meaning it has additives to prevent drinking.

Common questions

What is SD Alcohol 37 in beauty products?

SD Alcohol 37 is a type of alcohol that has been denatured (made unfit to drink) for use in cosmetics. It evaporates quickly, which helps products feel lightweight and dry fast, and it can kill bacteria on the skin. However, it can also strip the skin of its natural oils, leading to dryness, irritation, and a compromised skin barrier if used too often or in high amounts.

What does SD Alcohol 37 do in a beauty product?

When applied to the skin, SD Alcohol 37 evaporates rapidly, which can make the skin feel tight and clean. It also helps other ingredients penetrate more easily by temporarily disrupting the skin's barrier. Its antimicrobial properties can reduce surface bacteria, which is why it's often used in acne products.

Is SD Alcohol 37 safe for most people?

SD Alcohol 37 is generally safe for cosmetic use at typical concentrations, but it can cause dryness and irritation, especially for sensitive skin. The Cosmetic Ingredient Review (CIR) panel has deemed denatured alcohol safe when formulated properly, but caution is advised for frequent use on compromised skin.

Who should be careful with SD Alcohol 37?

People with dry, sensitive, or eczema-prone skin Anyone with a compromised skin barrier or rosacea

Research sources

Cosmetic Ingredient Review (CIR) - Safety Assessment of Alcohol Denat.OpenPubMed - Effects of Alcohol on Skin BarrierOpenFDA - Denatured Alcohol in CosmeticsOpen

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.