Hydrogen Peroxide vs. Bleach: What Actually Kills Mold?
When it comes to mold, not all cleaners work the same β and knowing the difference matters.
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Hydrogen Peroxide (3%)
How it works:
Hydrogen peroxide penetrates porous surfaces and kills mold at the root. It also helps remove staining left behind.
Pros:
Kills mold and bacteria
Works better on porous surfaces
Less harsh fumes
Breaks down into water + oxygen (more eco-friendly)
Best for:
β’ Drywall (small areas)
β’ Wood
β’ Grout
β’ Bathroom surfaces
β’ Upholstery (spot test first!)
Avoid using on:
Natural stone (can etch marble, granite)
Dark fabrics (can cause lightening)
Delicate finishes without spot testing
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Bleach (Sodium Hypochlorite)
How it works:
Bleach kills surface mold and whitens stains β but it does not penetrate porous materials well. That means mold roots can survive underneath.
Pros:
Disinfects hard, non-porous surfaces
Fast-acting
Whitens stains
Best for:
β’ Tile
β’ Glass
β’ Tubs
β’ Sealed countertops
β’ Non-porous bathroom surfaces
Avoid using on:
Wood
Drywall
Carpet
Upholstery
Stainless steel (can corrode)
Natural stone
Mixing with vinegar or ammonia (dangerous fumes 
)
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Important:
If mold keeps coming back, itβs usually a moisture issue β not a cleaning issue. Fix the leak, humidity, or ventilation problem first.
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The Bottom Line:
β’ Bleach = surface-level disinfectant.
β’ Hydrogen peroxide = better penetration for small mold spots.