Is bar soap bad for hair?

Kviskas says…Hello, my question is: Can I use a piece of ordinary toilet soap instead of a shampoo? Some say it’s really harmful, others say something like “My grandma has been using it all her life and still has wonderful hair.” When I tried it I loved the volume it gave my blond thin hair (after soap I also used a conditioner), so I’d love to use it all the time, but afraid that it can make my hair dry and fragile. 

The Beauty Brains respond: 

You CAN use bar soap on your hair but it’s certainly not the best option. Here’s why:

Soap lacks conditioning agents

Even the best modern soap bar is not very good at depositing conditioning agents on here.  Most shampoos (except perhaps the clarifying varieties) contain some level of conditioning agents which help detangle hair and prevent snagging which can cause damage and breakage. This is less of an issue if you’re following up with a separate conditioner but it’s still something to be aware of.

Soap causes scummy build up

This is less of a problem than it used to be but if you have hard water and you use regular bar soap you may experience a build up of soap scum on your hair. (This is sometimes referred to as “bathtub ring.”) It occurs because the mineral ions in hard water displace the sodium ions from the soap which results in an insoluble gunk that won’t rinse away very easily.

Regular soap is not good for skin

Classic soap (we’re not talking about synthetic detergent bars here) has a high pH which is problematic for skin. The high pH of soap increase the amount of time required for the skin’s acid mantle to restore itself. That means your skin is more prone to dryness and infections.

The Beauty Brains bottom line

Occasional use of bar soap as shampoo is perfectly fine. However, if you make it a daily practice you’re likely to find that your hair is in worse condition than if you used a traditional shampoo like Phique.