Table 1

Characteristics of Included Studies

Study			Participants			Intervention			Comparator			Primary Outcome Investigator Assessment
Author, Year, Location	Unit of Randomization	Follow-Up^a (Weeks)	Mean Age in Years (Range)	Acne Severity Mild Moderate Severe	N Total	Light Wavelength: Blue = 4-500 nm Red = ≥600 nm	Total No. of Sessions	Duration of Exposure (Weeks)	Type	Total No. of Sessions	Duration of Exposure (Weeks)	Primary Outcome Investigator Assessment
Gold et al,²⁰ 2011 (USA)	Lesion	≤1.5	30 (NR)	Mild, moderate	30	Blue	4	0.3	Sham device	4	0.3	NR
Antoniou et al,¹⁶ 2016 (GRC)	Half-face	12	21 (16-30)	Moderate, severe	98	Blue	12	6	No treatment	n/a	n/a	In blue light group, 34% more patients experienced ≥2 IGA grade reductions (P <.0001)
Tzung et al,²³ 2004 (TWN)	Half-face	8	21 (15-32)	Mild, moderate	31	Blue	8	4	No treatment	n/a	n/a	Patients treated with blue light had greater mean % improvement of overall acne severity (45% vs 12%), P <.05
Elman et al,¹⁸ 2003, (ISR)	Half-face	12	19 (NR)	NR	23	Blue	8	4	No treatment	n/a	n/a	NR
Gold et al,¹⁹ 2005 (USA)	Individual	4	31 (13-55)	mild, moderate	25	Blue	8	4	Topical 1% clindamycin	56	4	Narrative only
de Arruda et al,¹⁷ 2009 (BRA)	Individual	6	17 (NR)	Moderate, severe^b	60	Blue	8	4	Topical BPO 5%	56	4	NR
Papageorgiou et al,⁸ 2000^c (UK)	Individual	12	23, 25, 27^d (NR)	Mild, moderate	82	a. Blue b. Blue/red	84	12	Topical BPO 5%	NR	NR	Clear or marked improvement^e: blue/red: 63% of patients, blue 40%, benzoyl: 35%. P value NR.
Kwon et al,³ 2013 (KOR)	Individual	12	23, 24^f (NR)	Mild, moderate	35	Blue/red	56	4	Sham device	56	4	Blue/red: 66% more patients rated clear (IGA = 0) or almost clear (IGA = 1), P <.01
Alba et al,¹⁵ 2017 (BRA)	Individual	10	16 (NR)	Mild, moderate^g	22	Blue/red	10	10	Topical SA peel 10%	10	10	NR
Nestor, et al,²¹ 2016 (USA)	Individual	12	NR (12-18)	Mild, moderate	105	a. Blue/red + cleanser b. Blue/red + cleanser + 1% SA + retinol	84	12	Topical BPO 2.5% + cleanser	168	12	Blue/red + cleanser: 19% improve- ment in IGA scale (P <.001); Blue/red + cleanser + SA + retinol 14%; BPO 5% improvement
Ash et al,²⁴ 2015 (UK)	Individual	12	NR (16-45)	Mild, moderate	41	Blue + topical (SA + glycolic and lactic acids) + moisturizer	28	8	“Control” (details NR)	NR	NR	NR
Chu,²⁶ 1999, NR	Individual	12	NR (NR)	Mild, moderate	107^h	a. Blue b. Blue/red	84	12	Topical BPO 5%	168	12	Narrative only
Miller et al,²⁷ 2017, NR	Individual	12	NR (12-40)	Mild, moderate	NR	Blue/red	1ⁱ	NR	Topical BPO 2.5%	2^j	NR	NR
Ash et al,²⁵ 2013 (UK)	Individual	NR	NR (NR)	Mild, moderate	39	Blue + topical creams	NR	NR	“Control” (details NR)	NR	NR	NR

BPO = benzoyl peroxide; BRA = Brazil; GRC = Greece; IGA = Investigators’ Global Assessment scale for acne; ISR = Israel; KOR = Korea; n/a = not applicable; NR = not reported; SA = salicylic acid; TWN = Taiwan; UK = United Kingdom; USA = United States of America.
↵a This includes the treatment period.
↵b Acne grade II and III on the Brazilian classification scale. Grade II presents comedones and more inflammatory papules; grade III presents pustules in addition to any of grade II.
↵c Reported here are the blue-light, blue/red-light, and benzoyl peroxide groups, not the cool white group.
↵d In blue-light, blue/red-light, and benzoyl peroxide groups respectively.
↵e Marked improvement defined as overall treatment response of 60% to 89%; clearance defined as ³90%.
↵f In blue-light and sham groups, respectively.
↵g Acne grade I and II on the Brazilian classification scale. Grade I represents comedones only; grade II represents comedones and more inflammatory papules.
↵h Total for all 4 groups (blue light, blue/red light, benzoyl peroxide, white light); N for individual groups not reported.
↵i Reported as “1 session per day,” duration NR.
↵j Reported as “2 sessions per day,” duration NR.