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Is Propylene Glycol in Hair Products Bad for Hair and Scalp Health?

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Propylene glycol is a common ingredient in cosmetic formulations including shampoos, conditioners, leave-in conditioners, hair treatments, make-up, and skincare products.


But, is there a problem with having this chemical in contact with your hair or skin often by regularly using products with propylene glycol as an ingredient?


Some people may have no problem using propylene glycol in hair or skincare products, while others may have issues with it and want to avoid its use.


Below, we will cover the basics of propylene glycol as an ingredient as far as hair care products go, including why propylene glycol is sometimes used in the first place, if propylene glycol can be bad for the hair or scalp, what information we have on the subject, and what you can do if you want to avoid propylene glycol in your hair products.



What is propylene glycol?


Propylene glycol is a small water-soluble molecule with two alcohol groups attached (-OH) that is originally derived from petroleum.


And, while it is synthetically made from petroleum, that doesn’t mean that it automatically gets a red flag. It is best to look at the structure and functioning of the final chemical instead to get a feel for if this is an ingredient that you are ok with. Your specific reaction to products that contain propylene glycol is also a very important factor here.


The FDA considers propylene glycol to be “generally recognized as safe”. 



Why do some hair products include propylene glycol in the formula?


Propylene glycol can be a useful and multifunctional ingredient when it comes to hair and skin formulations. 


Propylene glycol is a humectant (attracts water), a solvent, an emulsifier, and has preservative properties. So, when trying to get a formula to perform how you want, this can be a useful ingredient for cosmetic chemists.


In the case of hair loss products specifically, propylene glycol is used in most over-the-counter Minoxidil (Rogaine) products due to its ability to help dissolve the hair loss active ingredient and increase its uptake from the tissues.



Can propylene glycol be bad for your hair and scalp?


Propylene glycol may be an issue for some people for a couple of reasons.


Firstly, propylene glycol maybe be irritating to the scalp for some users. It may cause allergic or irritant reactions like redness, burning, itching, flaking, or feeling dry or tender. Technically, if severe scalp irritation were left to persist, it could have a negative effect on the overall health of your scalp and hair.


Secondly, due to the humectant (water attracting) quality of the chemical, it can soak up and hold onto water from the surrounding air, skin, or hair that it is applied to. For some people, this may mean their hair feels more dry and brittle when using propylene glycol regularly. To help avoid this, you can use other moisturizing ingredients to help lock water into the hair shaft.



Do we have any evidence of propylene glycol being irritating to the scalp?


One small University of Oregon Department of Dermatology study patch tested 84 people with 100% propylene glycol to see if any skin reactions developed. 12 of the participants developed either allergic or irritant reactions to propylene glycol. So, it is possible that the skin can react to propylene glycol itself, although the study notes that skin reactions to propylene glycol are considered relatively rare.


Another study looked into patients who had reactions to the common over-the-counter hair loss combination of Minoxidil (Rogaine) plus propylene glycol, to see if irritation from the use of this common hair loss treatment was stemming from the Minoxidil or the propylene glycol. The participants were patch tested with the ingredients separately to identify the causative irritating agent. According to the study, propylene glycol was found to be the causative contact irritant in the majority of the cases, not the Minoxidil. Although it is possible to have a reaction from only the Minoxidil, or both agents, this was found less often.


For patients, this means that if you were using a medication like topical over-the-counter Minoxidil and had scalp reactions that lead you to stop treatment, you may be able to patch test to see if propylene glycol was the culprit. If it seems to be the cause of the irritation, it is possible that you can have your Minoxidil formulation compounded without propylene glycol and treat your hair with less risk of irritation.



Propylene glycol in hair products: Bottom line


Propylene glycol is commonly used in cosmetic products due to its antiseptic, solvent, moisture-regulating, and preservative properties.


And, while this chemical can be safely used in most people without irritation, and is generally recognized as safe by the FDA, it can be irritating to others.


For some users, they may develop allergic or contact irritant skin effects like redness, itching, dryness, flaking, burning, or feeling tender. Others may find that their skin or hair feels more dry when using propylene glycol-containing products.


Popular hair loss treatments like Minoxidil (Rogaine) or topical Finasteride tend to contain propylene glycol to help with the solubility and absorption of the active ingredients, and may be the root cause of scalp irritation in some users. If you have experienced irritation with formulas like these, but still want to use topical hair loss treatments, you may be able to find topical treatments that do not use propylene glycol in order to potentially avoid skin irritation. 



Strut Health propylene glycol free topical hair loss treatments


Here at Strut, we formulate our topical hair loss treatments without propylene glycol automatically to help avoid potential scalp irritation.


We focus on active ingredients like Minoxidil, Finasteride, Dutasteride, Spironolactone, Tretinoin, and Biotin combined into customized formulations to suit your specific hair loss needs and preferences. We offer gel, solution, or oral compounded formulations.


If you are interested in trying our propylene glycol free formulations, you can have a free online questionnaire and image-based telemedicine consultation with our U.S. licensed doctors today. If you are a good candidate for treatment, your prescription will be issued and your medication will be shipped to your door with our free shipping.


If you have any questions during your treatment, or need adjustments, our staff and doctors are available for free and unlimited follow-ups.


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