You can read about L. reuteri on ‘selfhacked.com’ this site is updated regularly & information is referenced.
NB> L reuteri can cause weight gain …. L Gasseri is good if you need to curb your appetite or sugar craving.
For skin problems my theory is that modern washing products destroy all our friendly bacteria on our skin, thus allowing bad bacteria, that become resistant to harsh products, to flourish, use just water to clean your skin if not very dirty, wash only dirty areas with simple soap, no shower gels etc & certainly nothing antibacterial. I never use soap on my face (too drying) I mix 1 teaspoon of neem powder into about 3 tablespoons of E45 cream (not lotion) mix well, use in shower as can be messy! use on feet for fungal infections. after drying appy E45 probiotic mix ( 1 teaspoon of E45 mixed with one (open) capsule of probiotic), I have used L Gasseri & Alflorex. sand down thick nails with emery board to allow better absorption. Use twice daily. I think my no sugar, no junk diet helps too + I take olive leaf capsules which are also anti fungal. After many miserable years of battling rosacea my skin is now clear.
Please note:- Please take adivice of your GP especially if you have any underlying problems with your immune system before using probiotics.