Taking human hair locs from 1B to 613 is not a simple color refresh. It is a full structural change.
A 1B base sits in the near-black family. A clean 613 finish is a very pale blonde. To cross that distance safely, you are asking bleach to do two jobs at once: remove deep natural pigment and leave enough strength behind for the loc to keep its shape, movement, and wearability. That balance matters even more with locs, because a loc is a dense rope of hair, not a loose sheet of strands.
The chemistry is effective because bleach oxidizes melanin, but that same process also oxidizes hair proteins and progressively damages the cuticle and cortex as bleaching severity increases, as shown in research on human hair fibers. Excess heat and overly aggressive bleaching can also lift cuticles and injure skin, with one study linking stronger peroxide exposure and unnecessary heating to visible hair and scalp damage during bleaching procedures.
So the safe version of 1B to 613 is not “How strong can I mix this?” It is “How conservatively can I lift this, while still ending with blonde that looks intentional?”
What makes locs different
Locs process differently from loose hair for three reasons.
First, saturation is harder. Bleach has to travel through the outer layer of the loc and into the packed interior, so patchy application shows up fast as dark threads, warmer bands, or stubborn cores.
Second, rinsing is harder. Powder lightener can linger inside a loc longer than you think, which means sloppy rinsing can quietly overprocess the hair after you think the service is done.
Third, locs often have uneven history. Mature ends, repaired sections, wrapped areas, sun-faded lengths, and extension joins rarely lift at the same speed. That is why a strand test is not optional here.
If the hair is installed, mature, previously dyed, or a blend of natural locs and extension hair, the safest expectation is multiple controlled sessions, not one heroic bleach day.
Before you chase 613, choose the right blonde
This is the part many people skip.
True 613 is bright, pale, and high-contrast. On locs, that reads bold and editorial, especially in daylight and flash photography. It can look striking, but it also exposes every bit of uneven lift. If your goal is softness, fuller-looking density, or easier maintenance, a warm beige, honey, or butter blonde often flatters locs better and asks less of the hair.
In other words: if your locs look beautiful at a level 8 or 9, stop there. Toner can refine blonde, but it cannot rescue under-lifted orange hair into a believable 613.
The safe chemical process
Start with the safety floor. Patch test every time, wear gloves, and do not bleach an irritated, scratched, or damaged scalp. The FDA also advises following package directions exactly, rinsing thoroughly, and not improvising by mixing different color systems together.
Then do a real strand test. Not a quick glance. A real test on a hidden loc, and if extensions are involved, on the extension hair too. Wella’s safety guidance recommends a strand test each time you color because previous chemical history, sun exposure, and texture all affect timing and result. With locs, that test tells you two things: how light the hair can get, and whether the fiber still feels strong enough afterward.
For the actual bleach session, conservative chemistry wins. The label on the exact lightener you are using is the rulebook. Professional lightener instructions vary, but examples from L’Oréal Professionnel and Wella Professionals show why freelancing is risky: direct on-scalp applications may be limited to 20-volume developer, many formulas ban added heat, and total processing time is commonly capped at about 50 minutes. That is especially relevant for locs, where trapped product and slower rinsing already increase risk.
Application order matters too. In most cases, mids and ends go first and roots go last, because scalp heat makes roots lift faster. On locs, work in small sections, fully coat the outside, then press product into the body of the loc without roughing it up. If you cannot see even saturation, the section is too big.
During processing, check visually and physically. Blonde that is getting lighter but still feels resilient is one thing. Hair that feels rough, gummy, overly stretchy, or hot is a stop sign. No target shade is worth pushing through that.
When it is time to rinse, rinse longer than you think you need to. Then rinse again. A loc can hold lightener in its center, and leftover bleach dust is exactly how a blonde service turns into hidden breakage two days later.
After rinsing and drying, reassess honestly. If the locs are still orange or deep gold, you are not at 613. Stop, treat the hair gently, and decide later whether it is strong enough for another lift. If the locs reached pale yellow and still feel sound, then toning makes sense.
Action checklist
- Confirm the locs are 100% human hair and free of heavy buildup, wax, and oils.
- Do a patch test 48 hours ahead and a strand test on a hidden loc or extension seam.
- Use one complete lightener system exactly as directed, with non-metal tools and gloves.
- Apply in small sections for full saturation, usually mids and ends first, roots last.
- Skip added heat, monitor frequently, and never exceed the formula’s stated max time.
- Rinse extremely thoroughly, dry the locs, then judge both color level and hair strength before toning or re-bleaching.
When to stop and hand it to a professional
Some locs should not be pushed at home.
That includes mature locs with years of product history, loc extensions already installed on the head, previously boxed-dyed black hair, weakened repair points, and any scalp that is tender, flaky, or compromised. If your strand test turns gummy, snaps when stretched, or stays unevenly banded, the safest move is not a stronger developer. It is a professional correction, or a different blonde goal.
From a style point of view, that restraint often gives the better result anyway. Locs with healthy shine, clean sectioning, and a believable warm blonde read more luxurious than damaged locs chasing an icy finish they cannot support.
FAQ
Q: Can 1B locs reach 613 in one session?
A: Sometimes, but not reliably and not safely for many locs. Dense mature locs, previously colored hair, and installed extensions often need more than one controlled lift. If the hair has not reached pale yellow, toner will not turn it into a clean 613.
Q: Is it safer to bleach loose human hair before making or installing loc extensions?
A: Usually yes. Loose human hair is easier to saturate evenly, easier to rinse completely, and easier to strand-test before commitment. Once the hair is locked and installed, both application and rinse-out get harder.
Q: What if my locs feel stretchy or gummy after bleach?
A: Stop all chemical work immediately. Rinse thoroughly, handle the hair gently, avoid heat, and do not attempt another bleach or toner service that day. If the scalp is burning, blistering, or swelling, seek medical care promptly.
Disclaimer
Bleaching, coloring, and heat styling can permanently weaken extension fibers. Always strand-test first, use compatible products, and work with a professional colorist when making high-lift or high-contrast changes.
