Thioglycolic Acid

Thioglycolic Acid and pregnancy

Not Recommended

• Absorbed into the body
• Irritant

Thioglycolic acid is a strong chemical compound used primarily in hair removal products and permanent wave solutions. It works by breaking down protein bonds in hair, which requires a potent chemical action that also poses risks to skin tissue. The primary concerns during pregnancy relate to potential systemic absorption through damaged skin barriers, especially if chemical burns occur from improper use. While specific teratogenic studies on topical thioglycolic acid are limited, the chemical's irritant nature and potential for skin damage create pathways for increased systemic exposure. Additionally, the strong odor can trigger nausea in pregnancy, and inhalation of fumes during application may cause respiratory irritation. ACOG does not have specific guidance on thioglycolic acid, but dermatologists generally recommend that pregnant women avoid chemical depilatories and hair straightening treatments due to the risk of chemical burns, absorption through damaged skin, and exposure to strong fumes. The combination of increased skin sensitivity during pregnancy and this ingredient's irritant properties makes it a high-risk choice during gestation.

Thioglycolic Acid and breastfeeding

Caution Advised

• Irritant
• Infant exposure

Thioglycolic acid is a strong chemical used in hair removal and straightening products. While systemic absorption from intact skin is limited, the ingredient's highly irritant nature can compromise skin barrier function. The primary concern during breastfeeding is not transfer into milk but rather potential contact exposure for breastfed infants if the product is applied to areas that may come in contact with the baby (such as arms or chest). Additionally, the strong chemical odor and potential for skin irritation make this a less-ideal choice during the postpartum period when skin may still be sensitive. While not absolutely prohibited during breastfeeding, dermatologists recommend caution with chemical depilatories and suggest avoiding their use on areas that directly contact the breastfed infant. If used, thorough washing and ensuring complete product removal is essential before infant contact.

Thioglycolic Acid and postpartum

Caution Advised

• Irritant

Thioglycolic acid can be used postpartum when not breastfeeding, but caution is warranted due to potentially increased skin sensitivity after pregnancy. Hormonal changes during the postpartum period can affect skin barrier function and irritation thresholds. If using products containing thioglycolic acid, follow all package directions carefully, perform patch tests, and monitor for increased sensitivity. The ingredient remains a strong irritant regardless of pregnancy or breastfeeding status, so proper application technique and timing are essential to prevent chemical burns.

Thioglycolic Acid and trying to conceive

Caution Advised

• Absorbed into the body
• Irritant

Thioglycolic acid is a strong chemical primarily used in hair removal products. While there is no direct evidence linking topical thioglycolic acid to fertility issues, its irritant nature and potential for systemic absorption through damaged skin suggest caution during the preconception period. Women trying to conceive may wish to minimize exposure to strong chemicals when possible, as conception timing can be unpredictable. While not as critical as during confirmed pregnancy, reducing exposure to irritant chemicals during the TTC period aligns with general preconception health recommendations.

Thioglycolic Acid and PCOS

Caution Advised

• Irritant

Thioglycolic acid is commonly found in chemical depilatories, which individuals with PCOS may consider for managing hirsutism (excess hair growth). However, this ingredient is a strong irritant that can cause chemical burns and skin damage with improper use. For those with PCOS experiencing excess hair growth, thioglycolic acid-based products may seem like a practical solution. However, the ingredient has no effect on hormonal pathways or underlying PCOS mechanisms—it only addresses hair cosmetically. Many individuals with PCOS have more sensitive skin due to hormonal fluctuations, which may increase susceptibility to irritation. If using chemical depilatories for PCOS-related hair concerns, exercise caution with products containing thioglycolic acid. Always follow timing directions precisely, perform patch tests, and consider gentler alternatives. The irritant nature of this ingredient makes it a less-than-ideal choice for those with already sensitive or hormonally-affected skin.

Thioglycolic Acid and general use

Caution Advised

• Irritant
• Common allergen

Thioglycolic acid is a potent chemical compound used in hair removal creams, depilatories, and permanent wave solutions. It functions by breaking down the protein bonds in hair, which requires strong chemical action that also poses risks to skin tissue if not used correctly. According to the FDA and SCCS, thioglycolic acid is a known irritant and sensitizer. It can cause chemical burns, allergic contact dermatitis, and skin damage if left on too long or used improperly. The FDA requires products containing this ingredient to carry specific warnings and usage instructions. Some individuals develop allergic sensitization after repeated use. When using products with thioglycolic acid, strict adherence to timing instructions is critical—never leave products on longer than directed. Always perform a patch test before first use, avoid using on broken or irritated skin, and ensure adequate ventilation during application. This ingredient requires careful handling and is not suitable for those with sensitive skin or a history of contact allergies.

Everything else flagged for the same profiles

• Flagged in pregnancy
• Flagged in breastfeeding
• Flagged in postpartum
• Flagged in trying to conceive
• Flagged in PCOS

Related ingredients

Ingredients that raise the same concerns.

• Citrus Aurantium Bergamia Fruit OilInfant exposure, Irritant, Common allergen
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Where this came from

Truva summarises published guidance from bodies including ACOG, the FDA, the EU SCCS and the Cosmetic Ingredient Review. It has no access to your medical history and it is not a substitute for your doctor, dermatologist or midwife. These assessments have not been reviewed by a clinician, and nothing here is a diagnosis or a prescription. If you are pregnant, breastfeeding or being treated for PCOS, take the ingredient list to the person looking after you.

Assessment last pulled from the ingredient database on 15 September 2026.