# Shampoo Without Propylene Glycol: What to Look For Instead

> Shampoo without propylene glycol (ACDS Allergen of the Year 2018): why PG is in shampoo, who reacts, how to read the label, and what replaces it.

*Updated: 2026-09-21*

**A propylene glycol-free shampoo is one whose INCI list does not include "Propylene Glycol," the small synthetic alcohol (1,2-propanediol) that formulators use as a humectant, solvent, and carrier for other ingredients.** Propylene glycol was the American Contact Dermatitis Society's Allergen of the Year for 2018, and it is unusual among allergens in that it causes both allergic and irritant reactions, which makes patch tests hard to read and avoidance the practical strategy. Shampoos that leave it out usually rely on glycerin, butylene or pentylene glycol, or 1,3-propanediol for the same job. A contact allergy to propylene glycol is a medical matter: read the full INCI and patch-test with a dermatologist or allergist before relying on any product.

**Fast facts**

- Propylene glycol (PG, 1,2-propanediol) is a colorless, odorless synthetic alcohol used in cosmetics as a humectant, solvent, emulsifier, penetration enhancer, and emollient.
- The American Contact Dermatitis Society named propylene glycol Allergen of the Year for 2018 (Jacob, Scheman, McGowan, Dermatitis 2018).
- DermNet reports that around 38% of products in the ACDS Contact Allergen Management Program database contained propylene glycol as of 2016.
- In North American Contact Dermatitis Group data from 1996 to 2006, 3.5% of 23,359 patch-tested patients reacted to 30% aqueous propylene glycol; the most common sources were personal care products and topical medications, including corticosteroid creams.
- PG is both a weak sensitizer and an irritant, so many patch-test reactions are weak and hard to classify; the ACDS core series tests it at 30% in water.
- "PG-free" is not a regulated claim, and the US FDA notes there is no federal definition of "hypoallergenic" or "for sensitive skin"; the INCI list is the check.
- Common replacements for PG in shampoo are glycerin, butylene glycol, pentylene glycol, and 1,3-propanediol; some related glycols have their own, less common, allergy reports.
- Baresel's humectants are glycerin and panthenol, and propylene glycol does not appear anywhere in its INCI.

## Why propylene glycol is in shampoo at all

Propylene glycol is cheap, water-soluble, and does several jobs at once. In shampoo it holds water against hair and skin (a humectant), dissolves ingredients that would not otherwise mix into a water base (a solvent), keeps the product from drying out in the bottle, and helps other actives penetrate. It is also used as the carrier in a great many topical medications, which is why dermatologists see it so often: DermNet notes it is reported as the most frequent allergen in topical corticosteroids. Because it is so useful and so widely permitted, it shows up across categories, from moisturizers and deodorants to hair products; the ACDS database put it in roughly 38% of listed products in 2016.

## Who reacts, and why PG is a difficult allergen

Propylene glycol is a weak sensitizer but a common one, simply because exposure is so widespread. In the North American Contact Dermatitis Group's 1996 to 2006 data, 3.5% of more than 23,000 patients had an allergic patch-test reaction to 30% aqueous PG, with personal care products the leading source. People with atopic dermatitis or an impaired skin barrier are over-represented, and DermNet notes the face is the most commonly affected site, followed by a generalized pattern. On the scalp, a rinse-off shampoo is a brief exposure, but hairline, ears, eyelids, and neck take repeated contact with the diluted lather, which is where reactions to hair products tend to show.

What makes PG awkward is that it irritates as well as sensitizes. At higher concentrations it disrupts the skin's lipid barrier directly, with no immune response involved, so a red patch on a test panel can mean allergy, irritation, or both, and the Allergen of the Year paper by Jacob and colleagues singles out this ambiguity as the reason PG is contentious. The Mayo Clinic's own series found positive rates rising steadily with test concentration (0% at 5%, 0.26% at 10%, 1.86% at 20%), which is consistent with an irritant component. In practice, a dermatologist weighs the test against your history and often recommends a trial of avoidance. That is the point at which a shampoo without propylene glycol becomes useful: not as a treatment, but as one fewer variable.

## How to read a shampoo label for propylene glycol

The INCI name is exactly **Propylene Glycol**, and in a shampoo it usually sits in the first half of the list, after water and the main surfactants. Be careful with look-alikes. **Butylene Glycol**, **Pentylene Glycol**, **Hexylene Glycol**, **Caprylyl Glycol**, and **Propanediol** (1,3-propanediol) are different molecules that do similar jobs; they are not propylene glycol, though a few have their own allergy reports and whether they suit you is a question for your own testing. **PEG** and **PPG** ingredients (polyethylene and polypropylene glycols) are polymers, not propylene glycol. And PG is a common carrier in botanical extracts, so an entry like "Chamomilla Recutita Flower Extract" may have been supplied dissolved in propylene glycol without that appearing on the finished label; a brand that discloses its raw-material carriers is easier to trust than one that does not.

**Humectants and solvents in shampoo, and what they are**

| INCI name | What it is | Relation to propylene glycol |
| --- | --- | --- |
| Propylene Glycol | 1,2-propanediol; humectant, solvent, penetration enhancer | The ingredient itself; ACDS Allergen of the Year 2018 |
| Glycerin | Glycerol, a three-carbon triol; humectant | A different molecule; the most common PG substitute for holding water |
| Panthenol | Provitamin B5; humectant and hair conditioner | Unrelated chemistry; conditions and holds water without PG |
| Butylene Glycol | 1,3-butanediol; solvent and humectant | Related glycol, not PG; occasional allergy reports of its own |
| Pentylene Glycol | 1,2-pentanediol; humectant with preservative-boosting effect | Related glycol, not PG; described in the literature as an emerging allergen |
| Propanediol | 1,3-propanediol, often corn-derived; solvent and humectant | An isomer of PG, not the same molecule; marketed as a PG replacement |
| PEG-/PPG- ingredients | Polyethylene / polypropylene glycol polymers | Polymers, not propylene glycol; a separate ingredient class |

## Where Baresel fits

Baresel is one shampoo whose humectants are glycerin and panthenol, with no propylene glycol, butylene glycol, or other glycol solvent in the formula. Its full published INCI is Aqua/Water, Sodium Cocoyl Isethionate, Sodium Methyl Cocoyl Taurate, Sodium Cocoyl Glutamate, Glycerin, Panthenol, Sodium Chloride, Guar Hydroxypropyltrimonium Chloride, Citric Acid, Sodium Benzoate, Potassium Sorbate, Tocopherol. This formula is confirmed with the manufacturer; the label on the bottle matches it, and you hear first if anything ever changes. It is also fragrance-free and preserved without MI/MCI or formaldehyde releasers, which are the other allergens that most often keep propylene glycol company on a patch-test report. Glycerin and panthenol are ingredients too, and a shampoo is a cosmetic rather than a treatment, so read the list against your own results with your dermatologist or allergist before use.

## Frequently asked

**Why is propylene glycol in shampoo?**

It is a cheap, water-soluble humectant and solvent: it holds water against hair and skin, dissolves ingredients that would not otherwise mix into a water base, keeps the product from drying out, and helps other ingredients penetrate. Those same properties make it one of the most widely used cosmetic ingredients.

**How common is propylene glycol allergy?**

In North American Contact Dermatitis Group data from 1996 to 2006, 3.5% of 23,359 patch-tested patients reacted to 30% aqueous propylene glycol, with personal care products the leading source. The American Contact Dermatitis Society named it Allergen of the Year for 2018.

**Is propylene glycol an irritant or an allergen?**

Both. It can cause true allergic contact dermatitis, but at higher concentrations it also irritates by disrupting the skin barrier directly, and it can cause contact urticaria and sensory stinging. That overlap is why weak patch-test reactions to it are hard to interpret and why a dermatologist may suggest a trial of avoidance.

**What replaces propylene glycol in a PG-free shampoo?**

Usually glycerin, sometimes with panthenol, or a related glycol such as butylene glycol, pentylene glycol, or 1,3-propanediol. Glycerin is a different molecule and the most common substitute; the related glycols are not propylene glycol but a few have their own, less common, allergy reports. Baresel uses glycerin and panthenol.

**Is propanediol the same as propylene glycol?**

No. "Propanediol" on a label is 1,3-propanediol, an isomer of propylene glycol (1,2-propanediol) with a different structure. It is often corn-derived and is marketed as a PG replacement. Whether it suits you is a matter for your own testing, not something the name guarantees.

**Will a propylene glycol-free shampoo fix my scalp?**

No shampoo treats or cures contact dermatitis; a PG-free one only removes a known trigger from your routine. If your scalp is reacting, see a dermatologist or allergist for patch testing, and check the full ingredient list of any new product against your results.

**Related reading**

- [Baresel ingredients, in full](/baresel-ingredients) — The complete INCI, with glycerin and panthenol as the humectants.
- [Get Baresel](/shop) — $22 for 250 ml; pre-order.
- [Fragrance-free shampoo for a sensitive scalp](/fragrance-free-shampoo-sensitive-scalp) — Fragrance is the most common co-reactor on a patch-test report.
- [Shampoo for a cocamidopropyl betaine allergy](/shampoo-for-cocamidopropyl-betaine-allergy) — The surfactant allergen most often found alongside PG.
- [What is cocamidopropyl betaine?](/what-is-cocamidopropyl-betaine) — Plain-language explainer on the other 'gentle' ingredient people react to.

**Sources**

- [DermNet — Contact allergy to propylene glycol](https://dermnetnz.org/topics/contact-allergy-to-propylene-glycol)
- [Jacob SE, Scheman A, McGowan MA. Propylene Glycol. Dermatitis 2018;29(1):3-5 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/29059092/)
- [Positive patch-test reactions to propylene glycol: NACDG 1996 to 2006 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/19321115/)
- [Patch testing to propylene glycol: the Mayo Clinic experience (PubMed)](https://pubmed.ncbi.nlm.nih.gov/29923851/)
- [US FDA — Allergens in Cosmetics](https://www.fda.gov/cosmetics/cosmetic-ingredients/allergens-cosmetics)

**Sources**

- [DermNet — Contact allergy to propylene glycol](https://dermnetnz.org/topics/contact-allergy-to-propylene-glycol)
- [Jacob SE, Scheman A, McGowan MA. Propylene Glycol. Dermatitis 2018 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/29059092/)
- [Positive patch-test reactions to propylene glycol: NACDG 1996 to 2006 (PubMed)](https://pubmed.ncbi.nlm.nih.gov/19321115/)
- [Patch testing to propylene glycol: the Mayo Clinic experience (PubMed)](https://pubmed.ncbi.nlm.nih.gov/29923851/)
- [US FDA — Allergens in Cosmetics](https://www.fda.gov/cosmetics/cosmetic-ingredients/allergens-cosmetics)