You can make your hair curly using heatless styling techniques, heated tools, or chemical treatments, depending on how long you want the curls to last. Temporary methods give you curls for a day or two, while professional treatments can last months. The approach that works best depends largely on your hair’s natural texture, its porosity, and how much time you’re willing to invest.
Why Some Hair Curls Naturally
Understanding a bit of hair science helps you work with your hair rather than against it. Hair texture comes down to the shape and angle of the follicle beneath your skin. Straight hair grows from round follicles that tunnel straight down into the skin. Curly hair grows from oval-shaped follicles set at an angle. The flatter the oval, the curlier the hair.
The protein that makes up your hair, keratin, contains an amino acid with sulfur-based chemical groups that form strong connections called disulfide bonds. Curly hair has more of these bonds because the follicle’s shape brings different parts of the strand closer together. Every method of making hair curly, whether it’s wrapping it around a robe tie or getting a professional perm, works by manipulating these bonds to reshape the strand.
How Water and Humidity Affect Curl
Your hair also contains weaker bonds called hydrogen bonds, and these are the ones you can temporarily break and reform at home. When hair absorbs water, it softens an internal gel-like structure, breaking hydrogen bonds and making the strand pliable. If you reshape the hair while it’s wet and let it dry in that new position, the hydrogen bonds reform in the new shape, holding the curl. This is the principle behind every heatless and wet-set curling method.
The catch: these hydrogen bonds break again the moment the hair gets wet or absorbs enough moisture from the air. That’s why curls from a wet set can fall flat on a humid day or wash out in the shower. It’s also why anti-humidity products and finishing sprays extend the life of temporary curls.
Heatless Curling Methods
Heatless techniques are the gentlest way to get curls, and they work well on most hair types. The general principle is the same for all of them: dampen your hair, wrap or pin it into shape, and wait for it to dry completely.
Robe tie or headband curls: You wrap sections of damp hair around a soft fabric strip (like a bathrobe belt or a thick headband) in a criss-cross pattern, then sleep in it overnight. For best results, leave the wrap in for a full night. If you’re short on time, a minimum of three hours will give you a softer, looser wave. This method tends to produce large, bouncy curls.
Pin curls: You wind small sections of damp hair into flat coils against your scalp and secure them with clips. Smaller sections create tighter curls, larger sections create waves. Pin curls work especially well on shorter hair where headband methods can be awkward.
Braids and twists: Braiding damp hair before bed is the simplest approach. A single loose braid gives you gentle waves. Multiple tight braids produce more defined, crimped texture. Two-strand twists work similarly and tend to create a more natural-looking wave pattern.
With all heatless methods, applying a lightweight styling product to damp hair before wrapping dramatically improves hold. Products containing film-forming ingredients coat the strand and help lock the new shape in place as it dries.
Heat Styling for Faster Results
Curling irons and wands deliver curls in minutes rather than hours, but they come with a tradeoff. Hair protein begins to break down at high temperatures, with research showing that significant structural damage starts around 237°C (about 450°F). At and above that threshold, the protein in the outer layer of the strand visibly degrades under microscopy.
To curl hair with heat while minimizing damage, keep your iron below 200°C (about 390°F) if your hair is fine or color-treated, and no higher than 220°C (430°F) for thick, coarse hair. Always use a heat protectant product, which creates a barrier between the hot surface and the strand. Wrap sections around the barrel for 5 to 10 seconds rather than clamping and holding, and let each curl cool completely before touching it. Curls set their shape as they cool, so brushing them out too early causes them to drop.
Using a Diffuser on Existing Texture
If your hair has any natural wave or curl that’s been hidden by years of brushing or heat styling, a diffuser attachment on your blow dryer can bring it back. Diffusers spread airflow through multiple vents and prongs instead of blasting a single concentrated stream, which dries hair without disrupting its natural curl pattern. Cup sections of hair into the diffuser, hold it close to your scalp, and use medium heat. The prongs lift the roots for volume while the dispersed air dries curls in place without creating frizz.
Professional Chemical Treatments
A perm is the only way to get curls that survive washing. The active ingredient in most perm solutions is a chemical that acts as a reducing agent, breaking the strong disulfide bonds inside the hair strand. Once those bonds are broken, the hair is wrapped around rods to set the new shape. A neutralizing solution then reforms the disulfide bonds in their new curved position, locking in the curl semi-permanently.
Modern perms are gentler than older formulations, and a skilled stylist can create anything from loose waves to tight spirals depending on the rod size and wrapping technique. Results typically last three to six months as the treated hair grows out. Permed hair needs more moisture than untreated hair because the chemical process opens the outer layer of the strand, making it more porous.
Choosing Products for Your Hair’s Porosity
How well your hair absorbs and holds moisture, its porosity, determines which products will help your curls last and which will weigh them down or leave them crunchy.
Low porosity hair has a tightly sealed outer layer. Water beads on the surface rather than absorbing, products tend to sit on top and build up, and the hair takes a long time to get fully wet or fully dry. If this sounds like your hair, stick with lightweight, water-based products containing humectants like glycerin. Avoid heavy butters and protein treatments, which can coat the surface and make hair feel stiff. Applying products to warm, damp hair (or using steam) helps open the outer layer enough for moisture to penetrate.
High porosity hair absorbs water almost instantly but loses it just as fast. It often feels dry, frizzes easily, and may be fragile. This porosity level benefits from layered products: a leave-in conditioner for hydration, an oil to seal it in (avocado oil works particularly well for high porosity strands), then a cream styler on top. Protein treatments help reinforce the strand’s structure. Be cautious with humectant-heavy products in humid climates, as they can pull too much moisture from the air and cause frizz.
Medium porosity hair absorbs and retains water well, reaching about 75% of its maximum absorption within four minutes. It responds predictably to most styling products and chemical treatments. A simple leave-in conditioner and a curl-defining cream or gel are usually enough.
Discovering Hidden Curls
Many people have natural curl or wave they’ve never seen because years of heat styling, brushing dry hair, and using sulfate-heavy shampoos have trained their hair to behave straight. Transitioning to a curl-friendly routine can reveal texture you didn’t know you had, but it takes patience. The process typically takes a few months to over a year, depending on how much previous heat or chemical damage your hair has sustained.
The basics of a curl transition involve switching to a sulfate-free shampoo that won’t strip natural oils, conditioning heavily, and letting hair air dry or diffuse instead of blow-drying it straight. During the transition, different sections of your hair may curl at different rates. Areas that experienced the most heat damage take longest to recover. Consistent deep conditioning helps improve curl uniformity over time.
Scrunching is a useful technique during this phase: after applying a styling product to soaking wet hair, cup the ends in your palm and squeeze upward toward the scalp repeatedly. This encourages strands to clump together and form curl groupings rather than separating into frizz.
Making Curls Last Longer
Regardless of how you create your curls, a few principles help them hold. First, hair must be completely dry before you release it from any set. Partially dry hair still has broken hydrogen bonds that haven’t reformed, and the curl will fall within an hour. Second, lightweight hold products applied before styling give hydrogen bonds a scaffolding to grip onto. Third, avoid touching your curls once they’re set. Each time you run your fingers through them, you break up the curl clumps and introduce frizz.
Sleeping on a satin or silk pillowcase reduces friction that pulls curls apart overnight. You can also loosely gather curls into a high, soft ponytail (sometimes called a “pineapple”) before bed to preserve the shape. Refreshing second-day curls with a light mist of water and a small amount of product, then scrunching, can revive curls without starting from scratch.