Ingredient
Benzisothiazolinone
Benzisothiazolinone is flagged for general use. The concern behind the strongest flag is common allergen and irritant.
- BIT
- 1,2-Benzisothiazol-3(2H)-one
Verdict by profile
Truva checks every ingredient against six profiles. Jump to any of them for the full assessment.
- Strongest verdict
- Caution Advised
- Its verdict for general use, the profile this one is worst in
- Profiles flagged
- 1 of 6
- Counting avoid, high risk and medium risk
- Irritancy
- 4 of 5
- Higher means more likely to sting or redden
Benzisothiazolinone and pregnancy
Safe to Use
- Irritant
- Absorbed into the body
Benzisothiazolinone is a preservative that prevents microbial contamination in cosmetic products. While it's primarily used to maintain product safety, its potential for skin sensitization makes it a consideration during pregnancy when skin can become more reactive. There are no specific studies linking BIT to reproductive harm or fetal development issues. The primary concern during pregnancy is increased skin sensitivity and potential allergic reactions, which pregnant women may be more prone to experience. Systemic absorption from topical cosmetics is minimal, and the EU's restricted concentrations further limit exposure. No regulatory body has identified BIT as a teratogen or pregnancy risk. Most dermatologists consider BIT-containing products acceptable during pregnancy when used at regulated concentrations. However, if you have a history of contact allergies or develop skin irritation, discontinuing use is advisable. The preservative's role in preventing harmful bacterial growth in products may actually provide safety benefits during pregnancy.
Benzisothiazolinone and breastfeeding
Safe to Use
- Irritant
As a preservative with minimal systemic absorption, benzisothiazolinone poses little concern for breastfeeding mothers. The compound works on the skin surface and in the product formulation itself, with negligible penetration into deeper tissues or bloodstream. There is no evidence suggesting BIT transfers to breast milk or affects milk production. The primary consideration remains skin sensitivity and potential contact dermatitis, particularly if products are applied to the breast area where direct infant contact could occur. The EU's concentration restrictions ensure limited exposure even with regular use. Dermatologists generally do not recommend avoiding BIT-containing products during breastfeeding unless you experience allergic reactions. If applying products near the breast area, ensure they are fully absorbed and wash hands before breastfeeding to prevent direct infant contact with any residue.
Benzisothiazolinone and postpartum
Safe to Use
- Irritant
For postpartum women not breastfeeding, benzisothiazolinone presents the same considerations as for the general population. The main concern remains its potential to cause contact allergic dermatitis in sensitive individuals. Postpartum skin can be more reactive due to hormonal fluctuations, which may increase the likelihood of developing sensitivity to preservatives like BIT. If you notice any redness, itching, or rash after using products containing this ingredient, discontinue use and consider patch testing. Otherwise, products with BIT at regulated concentrations are generally safe to use during the postpartum period.
Benzisothiazolinone and trying to conceive
Safe to Use
For women trying to conceive, benzisothiazolinone poses no known fertility concerns. There is no evidence linking topical exposure to this preservative with reproductive difficulties or hormonal disruption that would affect conception. The minimal systemic absorption and lack of endocrine-disrupting properties mean BIT does not interfere with fertility processes. Most fertility specialists do not recommend avoiding this preservative when trying to conceive, as it serves an important safety function in preventing product contamination.
Benzisothiazolinone and PCOS
Safe to Use
Benzisothiazolinone is a preservative with no known hormonal activity or effects on androgen levels, insulin sensitivity, or other PCOS-related pathways. It functions solely as an antimicrobial agent in cosmetic formulations. Women with PCOS often deal with acne and oily skin, and the preservative itself does not worsen these conditions beyond its potential for contact irritation in sensitive individuals. There is no interaction between BIT and PCOS symptoms or treatments. Products containing this preservative are safe for women with PCOS to use. The only consideration is the general risk of contact allergy, which is not elevated in PCOS populations compared to others.
Benzisothiazolinone and general use
Caution Advised
- Common allergen
- Irritant
Benzisothiazolinone is an effective preservative that protects cosmetic products from bacterial and fungal contamination. However, it is a well-documented contact allergen that can cause allergic reactions in sensitive individuals. According to the SCCS and dermatological research, BIT has been increasingly recognized as a cause of allergic contact dermatitis. The American Contact Dermatitis Society named it a notable allergen, and patch testing studies show rising sensitization rates in the population. Reactions can range from mild redness to severe dermatitis, particularly with repeated exposure. The EU restricts BIT concentrations to minimize allergic risk: maximum 0.01% in leave-on products and 0.05% in rinse-off products. If you have sensitive skin or a history of contact allergies, consider avoiding products with this preservative or performing a patch test before full application. Many brands now offer BIT-free alternatives for sensitive skin consumers.
Everything else flagged for the same profiles
Related ingredients
Ingredients that raise the same concerns.
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 .
One ingredient is the easy case.
A label has thirty of them. Truva reads the whole list at once and answers for the profile you set: pregnancy, breastfeeding, postpartum, trying to conceive, PCOS, or general use.
Download on theApp Store