This is a question we get so often. If we’ve been a part of your curly hair journey over the last couple of years. You would know this is a complete NO-NO. Wet curls and sleeping do not mix. We know it’s common particularly if you’re short on time but to want to deep condition overnight or allow your wet curls to air dry overnight but this can be tremendously damaging, let’s explain.

Hygral fatigue and your curls

Have you heard of the term hygral fatigue?

Hygral fatigue occurs when textured hair becomes damaged as a result of continued pressure on the hair fibre during periods of expansion and contraction. The expansion of the hair fiber occurs when the hair is wet, contraction occurs when it’s dry. If the hair is in an expansionary state for too long it can lead to a loss of elasticity, leading the hair to have a mushy or gummy like feel. Additionally, an excessive extension of curly hair textures in the expansionary phase for longer than optimal suggests that water has found its way to the inner most layer of the fiber and swollen to multiples – 1 – 3x its normal weight. What is this extra weight? It’s water weight.

Let’s put this into perspective, imagine what it would be like if you had double your body weight placed on your shoulders for hours on end? Not only will you be left fatigued, you’ll be left with chronic shoulder pain as our bodies are not designed to hold such weight for an extended period of time. Now, go back and view this through the lens of your curls, you could argue that your curls will eventually dry but at what rate? If it’s a quick refresh that needs to dry, this should ideally be no longer than 30-45 mins, this could be acceptable but we certainly would not recommend this to be repeated frequently.

Another reason people with curly hair may choose to sleep with wet hair is to get the “extra” conditioning benefits that supposedly come with leaving a conditioning treatment on for longer than suggested on the product instructions. It’s one thing to get carried away multi-tasking that you forget to wash out your deep conditioner in time - we’ve all fallen victim to the multi-tasking trap when short on time! However, doing so intentionally and repeatedly, poses a number of risks to your curls – over conditioned curls lose elasticity because the hair has absorbed more than the required amount of moisture, curls that are over conditioned lack bounce, appear more frizzy, gummy and stretchy, and are significantly more prone to breakage as the hair shaft has weakened, leading to split ends.

How long should I condition to get the maximum conditioning benefits? For deep conditioning treatments specifically scientists have told us that conditioning beyond 30-45mins provides no incremental benefits as your curls would have absorbed all the required moisture and nutrients in that time. However, our recommendation is through the lens of hair porosity levels. For high porosity curls, there is no benefit going beyond this. For low porosity curls, there could be a low % of incremental benefit assuming you are not using heat. We always advise low porosity curl types to utilise some form of heat for greater penetration and absorption in the hair shaft to help cut back on time spent conditioning. 

According to Dr Ali Syed the mastermind behind As I Am, in his book titled, Curly Hair, Structure, Properties and Care, states the optimal treatment time for low porosity curls is approx. 20-25 mins to which is an additional 10-15 mins to enjoy the same conditioning benefits via the level of absorption and penetration in the hair cortex as high porosity curls. 

With all our blog posts, we aim to give you relevant and reliable hair education for your curls without becoming extremely technical that you miss the key points. A relevant piece of hair education here is a high-level scientific understanding of what happens to our curls as they become wet. Hydrogen bonds, these bonds are responsible for hair’s ability to stretch i.e. hair elasticity. Hydrogen bonds are temporary (remember this key word – temporary!) and can be reconfigured or broken by water in order for new ones to form which allows for reshaping or restyling of your curls.

Wet curls and friction

Another reason to avoid sleeping with wet curls is due to the friction caused by unconscious movement when we sleep. Silk and satin fabrics provide the ultimate friction and frizz protection at night; however, this is on the basis that your curls are in their natural state. Wet curls have a higher chance of becoming extremely tangled especially curly hair, curls can become interlinked and hard to unravel without excessive tension used with a detangling brush or comb which yet still will lead to unnecessary breakage.

Sleeping with wet curls on silk or satin materials can also open your hair and scalp up to a bacteria and fungi which results in mould, most especially if you have not washed your silk or satin bonnet or scarf recently or regularly. This can lead to endless scalp issues and ultimately derail all the efforts made on your healthy hair journey.

Remember: Your curls are weakest and most vulnerable when wet, while this statement may appear concerning or negative at first glance, there are some positives, wet curls are easier to manipulate creating the perfect environment for styling for curl definition and elongation but the above risks should be taken into consideration.

Key takeaways for consideration:

- Sleeping with wet curls can lead to extremely damaged curls if done repeatedly.

- The degree of how wet your curls are is a key consideration, for example if you’ve just done a quick refresh of your curls vs. a full wash day routine.

- Hygral fatigue is real!

- Sleeping with wet curls is what we consider NOT to be a healthy hair habit and we do not recommend this.

- Scientifically speaking there are limited benefits to conditioning your curls beyond 30 mins, particularly, if you are using heat and have low porosity curls. Up to an hour is safe for low porosity hair provided that heat is not available to use.