Hey Linn😊
Thanks for your question!✨
The Ordinary GF Solution 15% does not contain retinoids or strong acids, which are often avoided during breastfeeding, so ingredient-wise it is okay. However, the manufacturer has not provided any clear information on whether the product has been tested or approved for use during breastfeeding as far as I can see.
I do see that it is listed as safe during pregnancy under "expecting skincare", but please talk to your doctor/midwife if you feel uncertain and if your skin is extra sensitive 🤱🏼
Wishing you a super nice day🌞