Bleaching your hair is a transformative process, opening the door to vibrant colors and lighter shades. However, re-bleaching already bleached hair is a delicate balancing act. Overdoing it can lead to significant damage, while under-processing leaves you with uneven or brassy results. So, how long can you really leave bleach on already bleached hair? The answer isn’t a simple number; it depends on several factors we’ll explore in detail.
Understanding Bleach and Its Effects on Hair
Before diving into timing, it’s crucial to understand what bleach does to your hair. Bleach, typically a mixture of hydrogen peroxide and an alkaline booster (like ammonia), works by oxidizing the melanin in your hair shaft. Melanin is the pigment that gives your hair its natural color.
This oxidation process essentially dissolves the melanin, lightening the hair. The longer the bleach is left on, the more melanin is removed, and the lighter your hair becomes. However, this process also weakens the hair’s protein structure, making it more susceptible to damage, breakage, and dryness.
The key is to lift the hair to the desired level while minimizing damage. When dealing with previously bleached hair, this becomes even more crucial because the hair is already compromised.
The Hair Structure and Bleach’s Impact
Your hair is composed of three main layers: the cuticle (outer layer), the cortex (middle layer), and the medulla (inner core). The cuticle acts as a protective shield, but bleach lifts and damages this layer to penetrate the cortex, where the melanin resides.
When the cuticle is excessively damaged, the hair loses its ability to retain moisture, leading to dryness and brittleness. The cortex, which provides strength and elasticity, can also be weakened, resulting in breakage and split ends. Already bleached hair has a cuticle that is, by definition, already compromised, making it more susceptible to further damage with each bleaching session.
Factors Influencing Bleach Processing Time on Previously Bleached Hair
Determining the optimal processing time for bleach on previously bleached hair involves considering several crucial variables. Each strand of hair is unique, and the condition of your hair, the products you use, and your desired outcome all play a significant role.
Hair’s Condition: The Most Important Factor
The most critical factor is the current condition of your hair. Is it dry, brittle, and prone to breakage? Or is it relatively healthy and resilient? Previously bleached hair is inherently more vulnerable than virgin hair.
Damaged hair will process faster and is at a higher risk of further damage. If your hair is already significantly damaged, you might want to reconsider bleaching altogether or opt for gentler alternatives like highlighting or using a toner.
Assessing the porosity of your hair is also crucial. Porosity refers to your hair’s ability to absorb and retain moisture. Highly porous hair absorbs bleach quickly but is also more prone to damage. Low porosity hair takes longer to process but is generally less susceptible to damage.
Volume of Developer: Controlling the Bleach’s Power
The developer volume significantly impacts the bleach’s lifting power and processing speed. Developers are available in different volumes (e.g., 10, 20, 30, 40), indicating the concentration of hydrogen peroxide.
A lower volume developer (10 or 20) is generally recommended for previously bleached hair because it processes more slowly and gently, reducing the risk of damage. Higher volume developers (30 or 40) lift faster but are much harsher and can easily lead to over-processing, especially on already compromised hair.
Using a lower developer allows for more controlled lifting and gives you more time to monitor the process and stop it before damage occurs. Remember, slow and steady wins the race when bleaching already lightened hair.
Desired Level of Lift: Setting Realistic Expectations
What are you hoping to achieve with the second bleaching session? Are you trying to lift your hair several levels lighter, or are you simply aiming to even out the tone or remove brassiness?
The amount of lift you’re trying to achieve directly impacts the necessary processing time. If you only need a slight lift, you’ll need to leave the bleach on for a shorter period than if you’re trying to drastically lighten your hair.
It’s important to be realistic about what you can achieve in one session, especially with previously bleached hair. Pushing your hair too far too quickly can lead to severe damage. Multiple, gentler sessions are often a better approach.
The Type of Bleach: Powder vs. Cream
Bleach comes in various forms, including powder bleach and cream bleach. Powder bleach is typically stronger and lifts faster than cream bleach. It’s generally mixed with a developer to create a bleaching mixture.
Cream bleach tends to be gentler and is often preferred for use on the scalp because it contains oils that protect the skin. Some cream bleaches are pre-mixed, while others require mixing with a developer.
For already bleached hair, cream bleach might be a better option due to its gentler formulation. It still lifts effectively but reduces the risk of rapid damage compared to powder bleach.
Environmental Factors: Heat and Humidity
Environmental factors like heat and humidity can also influence the speed at which bleach processes. Heat accelerates the chemical reaction, causing the bleach to lift faster.
If you’re bleaching in a warm environment, you’ll need to monitor the process more closely and potentially reduce the processing time. Humidity can also affect processing time, although to a lesser extent.
It’s generally best to bleach your hair in a cool, well-ventilated area to ensure even processing and prevent overheating.
Step-by-Step Guide: Applying Bleach to Already Bleached Hair
Bleaching already bleached hair requires meticulous preparation and careful application. Here’s a step-by-step guide to help you minimize damage and achieve the desired results.
Preparation is Key: Protecting Your Hair
Before you even open the bleach, take steps to protect your hair. Avoid washing your hair for 24-48 hours before bleaching. This allows the natural oils to build up and protect your scalp from irritation.
Consider applying a deep conditioning treatment or hair mask a few days before bleaching to hydrate and strengthen your hair. Using a bond-building treatment like Olaplex or similar products can also help to minimize damage during the bleaching process.
Gather all your supplies: bleach, developer, mixing bowl, applicator brush, gloves, a towel, and a timer. Have everything readily available to avoid delays during the application process.
Mixing the Bleach: Following Instructions Carefully
Follow the manufacturer’s instructions carefully when mixing the bleach and developer. Use the recommended ratio to avoid creating a mixture that is too strong or too weak.
Always use a non-metallic bowl and applicator brush, as metal can react with the bleach and affect its effectiveness. Mix the bleach and developer thoroughly until you achieve a smooth, creamy consistency.
If using a toner after bleaching, ensure you have that ready too, as it needs to be applied immediately after rinsing the bleach out.
Application: Precision and Speed
Apply the bleach to your hair in small, thin sections, starting with the areas that need the most lightening. This is usually the roots, but if you’re only refreshing the ends, focus on those.
Avoid overlapping the bleach onto previously bleached hair, as this can cause breakage and uneven results. Apply the bleach evenly, ensuring that all strands are thoroughly saturated.
Work quickly but carefully to ensure that the bleach processes evenly. Once the bleach is applied, set a timer and start monitoring the process.
Monitoring the Processing: The Most Crucial Step
This is the most crucial part of the process. Check your hair frequently, every 5-10 minutes, to assess the color lift. Gently wipe off a small section of bleach to examine the underlying color.
The goal is to lift the hair to the desired shade without over-processing it. If you notice any signs of damage, such as excessive breakage or elasticity, rinse the bleach out immediately.
Remember, previously bleached hair processes faster than virgin hair, so it’s essential to keep a close eye on the process.
Rinsing and Aftercare: Repairing and Hydrating
Once the hair has lifted to the desired level, rinse the bleach out thoroughly with cool water. Shampoo your hair with a sulfate-free shampoo designed for color-treated hair.
Apply a deep conditioning treatment or hair mask to replenish moisture and repair any damage. Leave the treatment on for at least 15-20 minutes before rinsing.
Consider using a bond-building treatment again after rinsing to further strengthen and protect your hair. Avoid using heat styling tools for at least 24-48 hours after bleaching.
General Time Guidelines: A Starting Point, Not a Rule
While there’s no one-size-fits-all answer to how long to leave bleach on already bleached hair, here are some general guidelines:
- For slight lift or toning: 5-15 minutes. This is for when you only want to slightly alter the tone or remove some brassiness.
- For lifting 1-2 levels: 15-30 minutes. If you’re aiming for a slightly lighter shade, this timeframe is usually sufficient.
- Maximum processing time: 45 minutes. Even on virgin hair, it’s generally not recommended to leave bleach on for longer than 45 minutes. On previously bleached hair, exceeding this time is almost guaranteed to cause significant damage.
These are just guidelines. Your actual processing time may vary depending on the factors discussed earlier. The most important thing is to monitor your hair closely and rinse the bleach out when it reaches the desired level of lift, regardless of the time.
Recognizing Signs of Damage: When to Stop Immediately
Knowing when to stop the bleaching process is crucial to prevent irreversible damage. Here are some signs that your hair is being over-processed:
- Excessive elasticity: When wet, the hair stretches excessively and doesn’t return to its original shape.
- Gummy texture: The hair feels soft, mushy, and gummy when wet.
- Breakage: The hair snaps easily when gently pulled.
- Severe dryness: The hair feels extremely dry, brittle, and straw-like.
- Scalp irritation: Burning, itching, or redness on the scalp.
If you notice any of these signs, rinse the bleach out immediately, even if the hair hasn’t reached the desired level of lift. Further processing will only exacerbate the damage.
Alternatives to Re-Bleaching: Gentler Options for Lightening
If you’re concerned about damaging your hair with another bleaching session, consider exploring alternative methods for lightening.
- Highlights: Highlights are a gentler way to add lightness to your hair without bleaching the entire head.
- Lowlights: Adding lowlights can create dimension and make your hair appear lighter overall.
- Color remover: Color removers can remove artificial pigment from your hair, revealing a lighter base color.
- Toner: Toners can neutralize unwanted tones (like brassiness) and create a more even, lighter appearance.
- Hair glosses: These can enhance shine and subtly alter tone without the damaging effects of bleach.
These alternatives can help you achieve a lighter look without the risks associated with re-bleaching already compromised hair.
How long is too long to leave bleach on previously bleached hair?
There isn’t a universal time limit. The ideal duration depends on several factors, including the strength of the bleach developer, the current condition of your hair, and the desired level of lift. Leaving bleach on too long, even by a few minutes, can cause significant damage, such as breakage, excessive dryness, and a rubbery texture. Regularly checking the hair’s elasticity and strand integrity during processing is crucial.
A good starting point is to process for no more than half the time you initially bleached your hair, and always err on the side of caution. Visually inspect the hair every 5-10 minutes. If you notice increased porosity, breakage, or the hair becoming overly stretchy, rinse the bleach immediately. Remember, it’s better to under-process and reapply than to over-process and risk severe damage.
Can I leave bleach on previously bleached hair overnight for maximum lightening?
Absolutely not. Leaving bleach on previously bleached hair overnight is extremely dangerous and will almost certainly lead to severe, irreversible damage. The extended exposure can cause the hair shaft to completely break down, resulting in significant hair loss, chemical burns to the scalp, and a compromised hair structure that won’t hold color or style.
Even low-volume developers used over extended periods are harmful. The active ingredients in bleach continue to process the hair as long as they’re present. This uncontrolled lightening can strip away vital proteins and moisture, leading to complete hair disintegration. Only a professional stylist, who can monitor the process closely, should handle bleaching previously processed hair, and even then, extreme caution is necessary.
What are the warning signs that bleach is damaging my previously bleached hair?
Several warning signs indicate that the bleach is damaging your previously bleached hair. One of the most obvious is a change in the hair’s texture. It might become excessively stretchy or gummy when wet, a sign that the protein structure is breaking down. Another sign is increased porosity, where the hair feels rough and dry, doesn’t hold moisture well, and takes a very long time to dry. Additionally, keep an eye out for breakage. If you notice excessive hair shedding or strands snapping easily, it’s a definite warning.
Scalp irritation, such as burning, itching, or redness, is also a critical signal to stop bleaching immediately. These symptoms suggest that the bleach is damaging the scalp. During processing, regularly perform a strand test by gently pulling on a few strands of hair. If they break easily, it’s a clear indication that the bleach is damaging the hair and needs to be rinsed out immediately. Continued processing after noticing these signs will result in further, potentially irreparable damage.
How does the developer volume affect the processing time on previously bleached hair?
The developer volume plays a crucial role in determining the processing time on previously bleached hair. Lower developer volumes (10 or 20) are gentler and cause less damage, making them preferable for previously bleached hair. They lift color gradually, reducing the risk of over-processing. Using a higher developer volume (30 or 40) on already bleached hair increases the risk of damage significantly. These higher volumes lift color quickly, but they can also quickly break down the hair’s protein structure, leading to breakage and dryness.
When bleaching previously bleached hair, always opt for the lowest possible developer volume that will achieve the desired level of lift. Monitor the hair closely and adjust processing time accordingly. It’s always better to under-process and reapply than to risk over-processing with a high-volume developer. If you’re unsure which developer volume to use, consult with a professional hair stylist.
Should I use heat with bleach on previously bleached hair?
Generally, it is best to avoid using heat with bleach on previously bleached hair. The added heat can accelerate the chemical reaction of the bleach, causing it to process faster and potentially leading to over-processing and damage. Previously bleached hair is already more fragile and susceptible to damage, and the heat can exacerbate these issues, causing breakage, dryness, and increased porosity.
If you must use heat, do so with extreme caution and for very short periods. Keep the heat setting low, and constantly monitor the hair’s condition. It’s usually safer to allow the bleach to process at room temperature, even if it takes a bit longer, than to risk damaging the hair with heat. Consider skipping heat altogether and simply allowing for a longer processing time at room temperature, regularly checking the hair’s elasticity and strength.
What aftercare steps are essential after bleaching already bleached hair?
After bleaching already bleached hair, it’s crucial to prioritize moisture and protein replenishment. Begin with a deep conditioning treatment specifically formulated for chemically treated hair. These treatments help to restore moisture lost during the bleaching process and strengthen the hair shaft. Following the deep conditioning, use a protein treatment to rebuild the hair’s structure and reduce breakage. Avoid heat styling for a few days after bleaching.
Ongoing maintenance should include using sulfate-free shampoos and conditioners to prevent further drying. Incorporate leave-in conditioners and hair oils into your routine to provide continuous hydration. Regularly trim your hair to remove split ends and prevent them from traveling up the hair shaft. Consider incorporating regular bond-building treatments into your haircare routine. These treatments can help repair and strengthen the hair’s internal structure, reducing breakage and improving overall hair health.
How often can I safely bleach previously bleached hair?
There’s no one-size-fits-all answer to how often you can safely bleach previously bleached hair, as it heavily depends on the individual’s hair condition, desired level of lift, and bleaching technique. However, a general guideline is to wait at least 6-8 weeks between bleaching sessions. Repeated bleaching can cause cumulative damage, weakening the hair and making it prone to breakage.
It’s crucial to prioritize the health of your hair over achieving a specific color quickly. If your hair is already damaged or brittle, consider postponing bleaching until its condition improves with intensive treatments and proper care. Only bleach the regrowth when needed, avoiding overlapping bleach onto previously lightened sections. If you’re unsure whether your hair can withstand another bleaching session, consult with a professional stylist.