โ† Back to List
Basic Laundry Knowledge

Laundry pH: Alkaline vs. Neutral Detergents, When to Use Which?

Published: February 10, 2026
Views: 41

๐Ÿ”ฌ The Science of Laundry: Optimal Guide for Using Alkaline vs. Neutral Detergents Based on pH Level

Laundry detergents are broadly divided into Alkaline Detergents and Neutral Detergents based on their ingredients and pH level (acidity/alkalinity). The detergent's pH level directly affects both cleaning power and fabric damage, so it is important to know exactly which detergent to use on which clothes. We provide an optimal guide for wisely choosing between alkaline and neutral detergents based on the type of laundry soiling and fabric material.


๐Ÿ”‘ Understanding Detergent pH: pH Level and Cleaning Principle

CategoryAlkaline Detergent (pH 8.5 and above)Neutral Detergent (pH 6.0 ~ 8.0)
Typical ProductsGeneral powder/liquid detergents, soap, sodium percarbonateWool shampoo, dish soap, slightly acidic detergents
Cleaning PrincipleHigh pH swells and separates fat and protein soiling (Powerful Cleaning)Neutral pH emulsifies soiling, cleaning without fiber damage (Mild Cleaning)
ProsPowerful cleaning power. Excellent for set-in grime, sebum, and oil stains.Minimal fabric damage. Preserves the color and shape of the fibers.
ConsRisk of fabric damage. Dyed colors may bleed, and protein fibers like wool/silk may be damaged.Weak at removing heavy set-in stains.
Optimal UseDurable general clothes like Cotton, Linen, Synthetic FibersDelicate/Protein fibers like Wool, Silk, Cashmere

๐ŸŽฏ The Formula for Detergent Selection by pH

You must accurately distinguish the detergent's pH to prevent fabric damage and maximize cleaning efficiency.

1. Neutral Detergent (Delicate Clothes and Color Protection):

  • Usage Target: Protein fibers like wool, cashmere, silk, and maintaining the waterproof coating on outdoor/sports functional wear.
  • Reason: These fibers are damaged when exposed to alkalinity (fiber structure is harmed, functional coatings peel off), so neutral detergent must be used.
  • Tip: Using neutral detergent for water washing minimizes color bleeding (fading), allowing clothes to remain vibrant for a longer time.

2. Alkaline Detergent (Powerful Cleaning):

  • Usage Target: Daily laundry and set-in grime removal for durable general clothes like cotton, linen, and synthetic fibers.
  • Reason: Alkaline detergent is most effective at separating acidic soiling from sweat and the oils from sebum. However, it should be avoided for high-cost or delicate materials.

3. Spot Soiling Treatment:

  • Acidic Stains (Coffee, Fruit): Neutralize and clean with alkaline detergent.
  • Alkaline Stains (Urine, Mud): Clean with neutral detergent, or neutralize with vinegar (acidic) before washing.

The basis of laundry is selecting a detergent with a pH appropriate for the 'fabric material.' Check the label and use the correct detergent.