<s>[INST] Does exposure to sunlight through a glass window reduce the skin’s ability to synthesise vitamin D? [/INST] Yes; exposure to sunlight through a glass window does not activate any vitamin D synthesis.  Source: Clinic Barcelona. Link: https://www.clinicbarcelona.org/en/assistance/diseases/osteoporosis/frequently-asked-questions. Field: Rheumatology. Disease: Ostoeporosis </s>