Systematic review of antioxidant types and doses in male infertility: Benefits on semen parameters, advanced sperm function, assisted reproduction and live-birth rate

Peer review under responsibility of Arab Association of Urology.

Figures & data

Fig. 1 PRISMA flowchart of literature search.

Table 1 Mechanism of action of commonly used antioxidants.

Antioxidant compound	Mechanism of action
Ascorbic acid (vitamin C)	Neutralises free radicals
Tocopherol (vitamin E)	Neutralises free radicals
Folate (vitamin B9)	Scavenges free radicals
Selenium	Enhancement of enzymatic antioxidant activity
Zinc	Inhibition of NADPH oxidase
Carnitines	Neutralises free radicals and acts as an energy source
CoQ10	In its reduced form, scavenges free radicals intermediate in mitochondrial electron transport system
NAC	Enhances enzymatic antioxidant activity
Lycopene	Quenches free radicals

NADPH, nicotinamide adenine dinucleotide phosphate.

Table 2 Proposed antioxidants in various clinical scenarios based on available evidence.

Clinical circumstance	Antioxidant	Reference
Basic semen parameters
Oligozoospermia	Vitamin E, vitamin C, NAC, carnitines, CoQ10, lycopene, selenium and zinc
	Vitamin E (300 mg)	[14]
	Vitamin E (180 mg), vitamin A (30 mg) and essential fatty acids or NAC (600 mg)	[33]
	NAC (600 mg) + other vitamins/minerals	[15]
	LC (2 g)	[16]
	CoQ10 (300 mg)	[17]
	NAC (600 mg) and selenium (200 µg)	[18]
	Folic acid (5 mg) + zinc (66 mg)	[19]
	Lycopene (2 mg)	[34]
Asthenozoospermia	Vitamin E, vitamin C, NAC, carnitines, CoQ10, lycopene, selenium and zinc
	Vitamin E (400 mg) + selenium (200 μg)	[35]
	Zinc (400 mg), vitamin E (20 mg) and vitamin C (10 mg)	[20]
	LC (2 g) and LAC (1 g)	[21]
	CoQ10 (300 mg)	[17]
	NAC (600 mg)	[22]
	NAC (600 mg) and selenium (200 µg)	[18]
	Lycopene (2 mg)	[34]
Teratozoospermia	Vitamin E, NAC, lycopene, selenium and zinc
	Vitamin E (400 mg) + selenium (200 μg)	[35]
	NAC (600 mg) and selenium (200 µg)	[18]
	Zinc (400 mg), vitamin E (20 mg) and vitamin C (10 mg)	[20]
	Lycopene (8 mg)	[36]
Advanced sperm function
High SDF	Vitamin E, vitamin C, zinc, selenium and folic acid
	Vitamin E (1 g) + vitamin C (1 g)	[23]
	Vitamin C (400 mg), vitamin E (400 mg), b-carotene (18 mg), zinc (500 µmol) and selenium (1 µmol)	[37]
	LC (1500 mg); vitamin C (60 mg); CoQ10 (20 mg); vitamin E (10 mg); zinc (10 mg); folic acid (200 μg), selenium (50 μg); vitamin B12 (1 μg)	[38,39]
OS	Vitamin E, vitamin C, NAC, selenium and zinc
	Vitamin E (300 mg)	[24]
	Vitamin E (180 mg) and β-carotene (30 mg)	[33]
	Vitamin E (20 mg), vitamin C (10 mg) and zinc (400 mg)	[20]
	Vitamin E (400 mg) and selenium (225 g)	[25]
	NAC (600 mg)	[22]
Improving success rate of ART	Vitamin E, vitamin C, lycopene, CoQ10, folic acid, selenium, zinc
	Vitamin E (200 mg daily)	[40]
	Lycopene (6 mg), vitamin E (400 IU), vitamin C (100 mg), zinc (25 mg), selenium (26 g), folate (0.5 mg) and garlic (1 g)	[26]
	Vitamin E (600 mg)	[29]
	Vitamin C (1 g) + vitamin E (1 g)	[42]
Live-birth rate	Vitamin E, vitamin C, carnitines, coQ10, and zinc
	CoQ10 (300 mg)	[17,41]
	Vitamin E (300 mg)	[24]
	Zinc (5000 mg)	[27]
	Vitamin E (1 g) + vitamin C (1 g)	[23]
	Carnitines: LC (2 g) + LAC (1 g/day)	[28]