Thioglycolic Acid Esters: Understanding Restrictions and Prohibitions for Lash Artists
As a lash artist, staying informed about ingredient safety regulations is crucial, especially when it comes to chemical treatments like eyelash perming solutions. One ingredient that has been under scrutiny is thioglycolic acid and its esters. Recently, thioglycolic acid esters were added to the list of prohibited substances due to their potential for skin sensitization, while thioglycolic acid and its salts remain restricted in specific applications. Understanding the difference between restricted and prohibited ingredients, as well as the distinct properties of thioglycolic acid and its esters, is essential for compliance and client safety.
Restricted vs. Prohibited Ingredients
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Restricted Ingredients: These can still be used in cosmetic formulations but must adhere to specific safety limits, pH constraints, and usage conditions. For example, thioglycolic acid and its salts are permitted in eyelash curling products at a concentration of up to 11% (as thioglycolic acid) with a pH of 9.5 or lower. Strict labeling and safety precautions, such as wearing gloves and avoiding skin and eye contact, are required.
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Prohibited Ingredients: These are completely banned in cosmetic applications due to significant safety concerns. Thioglycolic acid esters have been prohibited because a safe exposure level could not be determined. Additionally, studies indicate that glyceryl thioglycolate, a thioglycolic acid ester, can remain on permed hair for months, increasing the risk of prolonged skin sensitization and allergic reactions.
Thioglycolic Acid & Salts vs. Thioglycolic Acid Esters
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Thioglycolic Acid & Its Salts: These are used in hair treatments such as waving, straightening, and depilatory products. When formulated within regulatory limits, they remain permitted for professional use, with clear safety guidelines to minimize risks.
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Thioglycolic Acid Esters: These are chemically modified forms of thioglycolic acid and have been found to pose a greater risk of skin sensitization. Unlike the acid and its salts, esters such as glyceryl thioglycolate can persist in treated hair for extended periods, leading to prolonged exposure and a higher likelihood of allergic reactions, which is why they have been prohibited.
Regulatory History & Compliance
Thioglycolic acid has been regulated by Health Canada for several years due to its potential risks. It is included in Health Canada’s Cosmetic Ingredient Hotlist with strict concentration limits and pH requirements for use in cosmetic products, particularly in professional settings. Lash artists must ensure that any product they use complies with these restrictions to maintain client safety and regulatory compliance.
The Importance of Checking Safety Data Sheets (SDS)
Before using any product containing thioglycolic acid or its derivatives, it is essential to review the Safety Data Sheet (SDS). The SDS provides crucial information on handling, storage, first aid measures, and potential hazards associated with the ingredient. Ensuring you understand the risks and proper precautions can help prevent accidental exposure and skin sensitization.
What This Means for Lash Artists
If you use or are considering using eyelash perming products, always check the ingredient list for thioglycolic acid, its salts, or esters. Only products that comply with the 11% concentration limit (pH ≤ 9.5) and are labeled for professional use should be considered. Avoid any formulations containing thioglycolic acid esters, as they are now prohibited.
To ensure safety for both you and your clients:
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Wear gloves and avoid direct skin contact.
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Prevent exposure to the eye area.
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Educate your clients about potential risks.
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Check the SDS for every product you use.
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Stay up to date with regulatory changes.
By following these guidelines, you can continue offering safe and effective lash curling treatments while protecting the health of both you and your clients.
