Yes, more suds in your shampoo can be an indication that your hair is getting cleaner as long as those suds come from the surfactants (sulfates) in your shampoo. And don't worry, sulfates are not bad for your hair. Surfactants are substances that reduce surface tension, and are a key ingredient in many shampoos. And equally implant, that you’re not over washing your hair.
At the same time, more shampoo suds can also mean that you’re drying out your hair, or that you’re using a shampoo filled with “natural” marketing gimmicks that give you lots of foam, but don’t actually clean your hair. This is because of a hair myth from the early 1900's.
The association between a lather of suds and cleaning dates back to the use of bar soap for washing hair prior to the invention of liquid shampoo in the mid 1930s. Bar soaps left behind soap scum when mixed with hard water, which made hair feel dull and dirty. In comparison, the liquid shampoos created a lather and rinsed clean. And not long after, laundry detergents started to replace laundry soaps which had a similar effect. This is when marketers began using taglines like “Oceans of Suds” to convince people that the new detergents cleaned as well as laundry soaps.
Shampoo suds, or the lather, typically comes from the surfactants which are also used to clean your scalp. Two of the most common shampoo suds causing sulfates are sodium lauryl sulfate and sodium laureth sulfate. But more lather doesn’t necessarily mean more cleaning. Ever noticed all the shampoo bottles say “lather, rinse, repeat?” Well, that’s just a way to sell more shampoo.
The primary job of shampoo is to remove buildup, much of which is dirt and other stuff that mixes with the sebum your body produces to keep your scalp and hair naturally moisturized. Sebum actually inhibits the formation of bubbles that form a lather, so having more suds can mean you’ve already stripped your hair of all of the sebum and are just drying out your hair. This is why you notice a thicker lather if you actually do “repeat.”
And this can be especially damaging if you have color treated hair, because if you’ve already stripped the moisture and buildup from your hair, then the excess surfactants causing all those suds will attach to the color molecules and strip the dye from your hair faster than usual.
If you’re worried about keeping your color longer or have damaged hair, shampoos with cationic detergents like cetyltrimethylammonium chloride can be a good choice since they make your hair soft and manageable, but they won’t clean as well as sulfates and they won’t produce a rich lather.
Or if you have normal hair and want something more gentle than sulfate based shampoos, try amino acid–based surfactants like Sodium Methyl Cocoyl Taurate, which gives you a softer clean and still produces a lather while also providing more conditioning than sulfate based shampoos.
Just don’t get duped by the marketing machine behind natural surfactants from plants such as sarsaparilla, soapwort, soap bark, and ivy agave. These surfactants will create plenty of suds, but they do a poor job of cleaning your hair according to the NIH.
And now you know the truth behind the question about shampoo suds cleaning your hair. If you found this post interesting, subscribe below for more ways to keep your hair healthy.