Table 2.

Blue light in acne vulgaris.

Skin Disorder	Treatment Protocol	Irradiation Days Per Week	Irradiation Time	Wavelength, Intensity	Number of Patients	Outcome	Reference
Acne vulgaris (mild to moderate, facial, inflammatory)	every other day for 8 weeks, with final assessment 4 weeks post-treatment.	7	No information	414 nm	26 (treatment group), 15 (control group)	Reduction of inflammatory lesion by 50.02%. Maximum effect at week 8–12. After week 12 all patients achieved improvement.	[53]
Acne vulgaris (mild to moderate)	twice a week, with an interval of two days, for 4 weeks	2	20 min	405 +/− 10 nm blue light at the power of 30 mW/cm2	10 (blue light), 10 (red light)	Reduction of lesions by 71.4%. The mean number of lesions decreased from 19.2 to 5.5 after 8 irradiations.	[54]
Acne vulgaris	twice a week up to 5 weeks	2	No information	407–420 nm, 90 mW/cm2	30	Reduction of lesions by 64%. Within week 5 77% of patients achieved improvement.	[55]
Acne vulgaris	once or twice a week.	1–2	30 min (face), 45 min (back)	405 and 420 nm	10	Improvement was observed in 80% of patients	[56]
Acne vulgaris (mild to moderate facial acne)	twice a week for 4 weeks	2	14 min	415–425 nm (peak 420 nm)	21	Significant reduction of lesions	[57]
Acne vulgaris (facial acne)	Twice a week for 4 weeks	2	15 min	420 nm	28	Lesions improved by 64.7%	[58]
Acne vulgaris (mild-to-moderate inflammatory acne on the face)	Once a day for 8 weeks	7	6 min	414 nm	21	Reduction of open and closed comedomes, papules	[59]
Acne vulgaris (mild to moderate)	Twice a week for 4 weeks	2	10/20 min	409–419 nm at 40 mW/cm2	30	Reduction of lesions (at week 8–12)	[60]