What happens when you sew in extensions
A sew-in extension is braided into your natural hair in cornrows, then the weft (the sewn edge of the extension hair) is stitched to those braids with thread and a needle. The process takes two to four hours depending on how much hair you're adding and how many braids your stylist creates. Once sewn in, the extensions stay in place for six to eight weeks before they need to be removed, re-braided, and reinstalled.
The extensions themselves don't damage your hair if installed and maintained correctly. The risk comes from tension on the braids—if they're too tight, they can cause traction alopecia (hair loss from constant pulling). That's why the braid pattern and thread tension matter as much as the hair quality itself.
Key Takeaways
- Sew-in extensions are stitched onto cornrow braids that your stylist creates close to your scalp, and the process takes two to four hours.
- Braids that are too tight cause permanent hair loss, so a good stylist creates loose, even braids and doesn't pull the thread too hard.
- You wash and condition sew-ins the same way as your natural hair, but you need to dry them fully to prevent mildew in the braids underneath.
- Sew-ins last six to eight weeks before the braids loosen and the extensions need to be removed and reinstalled.
- Removing extensions yourself risks breaking your natural hair; a stylist can take them out safely by cutting the thread and unbraiding without yanking.
Preparing your hair before the appointment
Wash your hair two to three days before your sew-in appointment. Your scalp needs to produce natural oils to protect it during the braiding process, so don't wash the day of. If your hair is tangled or matted, detangle it gently with a wide-tooth comb or your fingers while it's wet and conditioned.
If you have short hair, some stylists will recommend a pre-braiding treatment or protein deep conditioning to strengthen it before the tension of the braids. Ask your stylist what they recommend based on your hair type and length. Avoid heavy oils or products on your scalp the morning of your appointment—they can make the braids slip.
How the braiding and sewing process works
Your stylist will section your hair into four to eight large sections, depending on how much coverage you want. They'll then create cornrow braids in each section, starting close to the scalp and braiding down to the ends. The braids should be tight enough to hold the extensions but loose enough that you can fit a finger under them without discomfort.
Once the braids are done, your stylist will lay the weft of the extension hair along the braid and stitch it down with thread using a curved needle. They'll use a whip stitch or ladder stitch, which locks the weft to the braid without creating bulk. The thread should be tight enough to hold the hair but not so tight that it cuts into the braid or causes pain.
A good stylist will check the tension throughout the process and ask how it feels. If your scalp is burning or throbbing, tell them—that's a sign the braids are too tight and need to be loosened. Discomfort during installation often leads to hair loss weeks later.
Washing and caring for sew-ins at home
You can wash sew-in extensions just like your natural hair, but you need to be gentler with the braids. Use a sulfate-free shampoo and focus on your scalp and the roots of the braids. Avoid rubbing the weft or the extension hair itself—just let the shampoo run through it.
Condition the extension hair from mid-length to the ends, but avoid conditioning the braids themselves, as moisture trapped in the braids can cause mildew or mold. Rinse thoroughly with cool water to seal the cuticle of the hair.
Dry your hair completely before bed. Wet braids left damp overnight can develop odor and mildew. Use a blow dryer on low heat or let your hair air dry fully. Sleeping on wet braids also causes frizz and loosens the stitches.
Avoid chlorine and salt water, which can dry out the extension hair and loosen the stitches. If you swim, wet your hair with fresh water and explore leave-in conditioner first—this creates a barrier so the chlorine or salt doesn't absorb into the hair as much.
Styling and sleeping with sew-ins
You can style sew-in extensions with heat tools, but use a heat protectant spray first. The extension hair is already processed, so it's more fragile than your natural hair. Keep heat tools on medium to low settings and avoid direct heat on the weft or the thread, which can melt.
At night, braid your sew-ins loosely or put them in a high ponytail to reduce friction and frizz. Sleep on a silk or satin pillowcase if you can—cotton pillowcases create friction that causes breakage and frizz. Some people wrap their sew-ins in a silk scarf or bonnet before bed.
Avoid tight hairstyles during the day as well. Pulling the extensions back tightly puts extra tension on the braids and your natural hair, which speeds up loosening and increases the risk of traction alopecia.
When and how to remove sew-ins
Sew-ins typically last six to eight weeks. After that, the braids loosen as your natural hair grows, and the stitches start to slip. You'll notice the extensions moving around or the weft lifting away from the braid. That's the sign it's time to remove them.
Removing sew-ins yourself is risky—if you cut the thread wrong or pull too hard, you can break your natural hair. A stylist will carefully cut the thread with small scissors, unravel the braid gently, and separate the extension hair from your natural hair without yanking. The whole removal process takes 30 minutes to an hour.
After removal, your natural hair will need a break. Most stylists recommend waiting at least one to two weeks before reinstalling new extensions. During that time, deep condition your hair and scalp to recover from the tension and prepare for the next installation.
Signs of damage and when to stop wearing sew-ins
If you notice hair loss along your hairline, at the nape of your neck, or anywhere the braids were tight, stop wearing sew-ins when ready. Traction alopecia can become permanent if you keep pulling on the same areas. The hair loss may not be obvious until weeks after you remove the extensions, so pay attention to your hairline in the weeks following removal.
If your scalp is itchy, painful, or develops sores during the sew-in, that's also a sign the braids are too tight or your scalp is irritated. Remove the extensions and let your hair rest. You can try again with a different stylist who creates looser braids, or you can explore other extension methods that don't require braiding.
Some people's hair and scalp straightforward don't tolerate sew-ins well, no matter how carefully they're installed. If you've had two or three installations and experienced pain, itching, or hair loss each time, sew-ins may not be the right choice for your hair type.
Frequently Asked Questions
How much do sew-in extensions cost?
Installation costs vary widely depending on your location, the stylist's experience, and how much hair you're adding. Expect to pay anywhere from $150 to $600 for installation alone. The hair itself (usually sold by the bundle) costs extra and ranges from $20 to $200 per bundle depending on quality and length.
Can I wash my hair the day after installation?
Most stylists recommend waiting 24 to 48 hours before your first wash so the stitches have time to set. After that, you can wash as normal, but be gentle with the braids and make sure to dry your hair completely.
What if my braids start to itch?
Light itching is normal as your scalp adjusts. Use a scalp oil or leave-in conditioner spray to soothe it. If the itching is severe or painful, or if you see redness or sores, the braids are too tight and you should see your stylist to have them loosened or removed.
Can I reuse the same extensions after removal?
Yes, if the hair is still in good condition. After removal, wash the extensions gently, condition them, and let them dry completely. Store them in a cool, dry place. You can reinstall them at your next appointment, though the hair may not last as many installations as new hair.
How do I prevent my natural hair from breaking under sew-ins?
The key is loose braids, proper tension on the thread, and regular deep conditioning. Choose a stylist who specializes in protective styling and has experience with your hair type. Avoid tight hairstyles, sleep on a silk pillowcase, and take breaks between installations to let your hair recover.