Chemical burn on hairline from relaxer: how to recover your edges

Last updated 2026-07-10

What exactly happens to your hairline when a relaxer burns it?

A relaxer straightens hair by breaking the disulfide bonds in the shaft with a strongly alkaline chemical. Usually that is sodium hydroxide (lye) at a pH of 12 to 14, or guanidine carbonate (no-lye) at a slightly lower but still damaging pH around 9 to 11 ^[1]. When that chemistry sits on your scalp instead of moving through the hair, it keeps working. It digests proteins, wrecks the lipid barrier, and can reach the dermis where your follicles live.

The hairline is the weakest spot. The skin there is thinner than anywhere else on the scalp, and stylists (or you, at your bathroom sink) tend to smear relaxer right to the edge to lay those baby hairs flat. Overprocessing, overlapping onto already-relaxed hair, or leaving product on a few minutes past the recommended time raises the risk fast.

You feel tingling first. That part is normal chemistry doing its job. What is not normal is burning, a sting that keeps climbing, or pain that makes you want to claw at your scalp. Once the pain escalates, the alkali has already breached the top layer of skin. From there the damage moves deeper by the minute.

On a cellular level this is a liquefactive necrosis injury, the same category of burn caused by industrial lye ^[2]. The tissue does not char the way a heat burn does. It softens, proteins denature, and cells rupture. If the injury reaches the bulge region of the follicle, which sits roughly 1.5 mm below the skin surface, you can lose the stem cells that regrow hair ^[11]. That is the line between temporary and permanent.

How do I know if my hairline burn is serious enough to see a doctor?

Rinse fully, then watch the skin. If you see blistering, oozing, or skin that turns white, gray, or numb, get to a dermatologist or urgent care within 24 to 48 hours. Mild redness that fades within a few hours can usually be watched at home. The dividing line is simple: pain that keeps getting worse after you rinse means the burn is real tissue damage.

Most of us have felt a relaxer sting and shrugged it off. That shrug is fine for irritation. It is dangerous for a burn.

Get a dermatologist within 24 to 48 hours if you have any of these:

• Blisters or vesicles along the hairline
• Oozing, weeping, or crusty discharge
• Skin that looks shiny, white, or darkened next to the surrounding tissue
• Swelling that spreads past the original contact area
• Pain that persists more than an hour after rinsing
• Any patch of skin that feels numb (that is nerve territory)

These are less urgent and you can monitor them at home first:

• Redness that fades within a few hours
• Mild tenderness to the touch
• Light flaking or scaling that shows up 48 to 72 hours after the burn

The American Academy of Dermatology treats any blistering scalp burn as an injury that needs professional evaluation, because a second-degree scalp burn carries a real risk of scarring alopecia ^[3]. Scarring alopecia means the follicle gets replaced by fibrous tissue and hair stops growing there. That is the outcome you are fighting to prevent.

No dermatologist available fast? An urgent care clinic can assess burn depth and prescribe a short course of topical or oral steroids to calm inflammation before scarring sets in. Speed beats finding the perfect specialist.

What should I do immediately after a relaxer burns my hairline?

The first thirty minutes decide a lot. Rinse with cool running water for 15 to 20 minutes, skip oils until the chemical is fully off, and photograph the area. Then get a thin layer of aloe or 1% hydrocortisone on it. Everything below is that plan in detail.

Rinse with cool water for at least 15 to 20 minutes. Not lukewarm. Cool. Heat opens blood vessels and can push the chemical deeper into the tissue. You are trying to physically flush the alkali off. A showerhead beats a sink because the water keeps flowing ^[2]. Do not rub. Let the water do the work.

Neutralize with a pH-balanced rinse if one is within reach. Most relaxer kits include a neutralizing shampoo for exactly this. Use it gently. No neutralizer on hand? Diluted apple cider vinegar (one tablespoon to one cup of water) can help lower the pH, but the water rinse matters more. Never skip water to jump straight to vinegar.

Do not slather on oil or petroleum jelly right away. This feels backward, since those products soothe later, but putting them on before the alkali is rinsed off traps the chemical against your skin. Rinse first. Moisturize later.

Stop the rest of the service. No flat iron. No blow dryer. No more product on that hairline. The skin barrier is already broken and cannot handle extra chemical or heat.

Document the burn. Take clear photos as soon as you can. You will want them for a doctor, for any dispute with a salon about what happened, or just to track how the skin heals week to week.

After the rinse, a thin layer of pure aloe vera gel or over-the-counter 1% hydrocortisone cream calms the immediate inflammation. Both are low-risk on a scalp wound. Keep anything with alcohol, fragrance, or minoxidil off broken skin, because all three will sting and can make the irritation worse.

How long does it take for a burned hairline to heal and start regrowing hair?

Skin closure and hair regrowth run on two separate clocks. Skin usually closes in 5 to 10 days for a mild burn and 2 to 4 weeks for a blistering one. Regrowth is slower and depends entirely on whether the follicles survived: expect nothing for 3 to 6 months even in the best case, and up to 12 months if the follicle was hurt but not killed. People mix these two timelines up constantly.

Skin healing goes first. A mild first-degree burn (redness, no blisters) usually clears in 5 to 10 days. A second-degree burn with blistering can take 2 to 4 weeks to fully close. During that window the area is open to infection and hyperpigmentation ^[3].

Hair regrowth rides on follicle survival. The anagen (active growth) phase of scalp hair lasts 2 to 7 years, but a traumatized follicle often drops into a resting telogen phase right after the injury. You may see nothing new for 3 to 6 months even when the follicles are intact. If a follicle was damaged but not destroyed, regrowth can stretch to 12 months and the first hairs often come in finer.

See zero regrowth at the 6-month mark? That is when a dermatologist can run a scalp biopsy to check whether follicles are still there or whether fibrous tissue has taken over ^[3]. Nobody has solid population-level data on what share of hairline relaxer burns end in permanent loss versus temporary shedding. The clinical consensus is that fast treatment and keeping the area inflammation-free make a big difference in the odds.

The table below gives a rough healing timeline by severity.

Burn severity	Skin closure	First regrowth possible	Full regrowth possible
Mild (redness only)	5-10 days	3-4 months	6-9 months
Moderate (blistering, no scarring)	2-4 weeks	4-6 months	9-12 months
Severe (scarring/scab formation)	4-8 weeks	6-12 months	May be permanent

One thing the table cannot show: aftercare consistency matters as much as severity. Follicles that stay inflamed, from too-tight styles, repeat chemical exposure, or an infected wound, recover much slower.

Mild burn: skin closure (days)	10
Mild burn: first regrowth possible (weeks)	16
Mild burn: full regrowth possible (weeks)	36
Moderate burn: skin closure (weeks)	4
Moderate burn: first regrowth possible (weeks)	24
Moderate burn: full regrowth possible (weeks)	52
Severe burn: skin closure (weeks)	8
Severe burn: first regrowth (weeks, if any)	52

Source: American Academy of Dermatology and NIH wound healing literature (citations 3, 4)

What treatments actually help the scalp heal after a relaxer burn?

The short list with real evidence: early topical corticosteroids, moist wound care with petrolatum, and minoxidil once the skin is fully closed. Everything else is hopeful but thinner on proof. Here is the honest split.

What has real support:

Topical corticosteroids (1% hydrocortisone over the counter, or stronger prescription formulas) cut acute inflammation and can limit the scarring response if you start early ^[4]. Dermatologists often prescribe these for the first 2 to 4 weeks after a significant burn.

Keeping the wound moist with a fragrance-free barrier like petrolatum or a wound-healing ointment (Aquaphor is the usual pick) speeds epithelialization compared to letting the wound dry out ^[4]. This is basic, well-settled wound care.

Minoxidil 2% or 5% has evidence for regrowing hair in non-scarring alopecia ^[5]. The NIH literature database holds multiple randomized controlled trials backing its use. If your dermatologist confirms the follicles are still there, minoxidil applied after the skin has fully healed (never on open or broken skin) is a reasonable add.

What is less proven but low-risk:

Rosemary oil has one 2015 randomized controlled trial (Panahi et al., in SKINmed) showing it worked about as well as 2% minoxidil for androgenetic alopecia at 6 months ^[6]. The study never looked at post-chemical-burn regrowth, so I will not oversell it. Its anti-inflammatory and circulation effects make it a fair adjunct once the skin has closed. If you want to try it, rosemary oil for hair growth breaks down safe use.

Biotin and other oral supplements are everywhere, but the evidence that biotin helps regrowth in people who are not actually biotin-deficient is weak ^[7]. Taking it will not hurt you. Do not expect it to replace real wound care.

What to avoid completely during recovery:

• Another relaxer on or near the burned area for at least 8 to 12 weeks, and only after full healing plus a dermatologist's clearance
• Tight edges, braids, weaves, or any style that pulls the hairline (this stacks a second injury on the first and slides into traction alopecia territory)
• High-alcohol edge control, which strips the little barrier that is left
• Heat styling directly over the affected zone

Can a relaxer burn cause permanent hair loss on the hairline?

Yes. A relaxer burn causes permanent loss when it destroys the follicular stem cells in the bulge region. Once scar tissue replaces those cells, the follicle is gone for good: no product, no treatment, and no amount of time brings it back. The skin closes, but it closes smooth and bare. This is the part people find out too late.

Doctors classify this as scarring alopecia, specifically chemical-induced cicatricial alopecia ^[3]. The AAD notes that scarring alopecias as a group affect an estimated 3% of hair loss patients seen in North American dermatology practices, though the share caused by chemical burns is not broken out in most datasets ^[3].

The risk factors for permanent loss from a relaxer burn:

• Leaving the relaxer on past the manufacturer's recommended time
• Applying relaxer to a scalp that already has sores, psoriasis, seborrheic dermatitis, or any break in the skin
• Repeat chemical burns in the same spot over months or years
• Waiting to treat it and letting the inflammation drag on
• Infection of the wound during healing

If you already have significant scarring, a dermatologist can do a punch biopsy to check follicular density in the scarred area. Some patients with focal scarring alopecia can qualify for a hair transplant once the underlying inflammation has fully settled, usually after 1 to 2 years of stability ^[3].

Here is the honest part: nobody can tell from a photo or a description whether your follicles are gone. A clinical exam, and a biopsy if needed, are the only ways to know.

How do I protect my edges and hairline while they recover?

Recovery is not passive. The single most protective move is taking every bit of tension off the hairline while it heals. That means no braids, cornrows, weaves, tight ponytails, or gripping headbands over the area. Keep the scalp clean with a gentle sulfate-free wash, and once the wound closes, moisturize the skin daily.

Tension is the enemy here. Anything that pulls restricts blood flow and adds mechanical stress to follicles that are already hurt. The traction alopecia and hair breakage pages go deeper on the mechanism, but the short version: a burned follicle and a pulled follicle both send distress signals, and both signals at once are worse than either alone.

For the rest of your head while the edges heal, protective hairstyles that skip hairline tension are your friend. Loose twists, low buns tied with scrunchies instead of tight elastics, and wigs on a cap placed well back from the burned zone all work.

Keep the scalp clean but gentle. A sulfate-free, fragrance-free shampoo once or twice a week stops buildup and lowers infection risk without stripping the barrier. Pat dry. Never rub.

Moisturize the healed skin daily. Once the wound has closed (no open areas, no oozing), a lightweight oil on the hairline supports the barrier. Jamaican black castor oil and jojoba oil both have reasonable safety profiles on healing skin, though the evidence for their direct effect on regrowth is anecdotal, not clinical.

Edge control gets a specific warning. Many popular formulas pack high concentrations of alcohol and synthetic polymers that dry the hairline with repeat use. During recovery, skip edge control entirely on the affected zone. When you do go back to styling products, edge control that is water-based and alcohol-free is the safer pick.

For products built around edge regrowth, Edge Naturale's collection focuses on plant-based ingredients for the hairline zone. Worth a look once your skin is closed and you are in the active regrowth phase.

What natural ingredients are safe to use on a healing hairline after a relaxer burn?

Pure aloe vera is the safest bet for soothing near-closed skin, and diluted tea tree oil can help ward off infection. Wait until the wound has fully closed before castor oil, rosemary oil, or any other oil. People reach for natural remedies almost the second a burn happens. Some genuinely help. Some make things worse. Here is the honest breakdown.

Aloe vera gel (pure, no additives): Good evidence for soothing and calming inflammation. A 2007 review in the Journal of Ethnopharmacology found aloe vera sped up wound healing in first and second-degree burns compared to conventional dressings across several trials ^[8]. Apply a thin layer to closed or nearly-closed skin. On an open wound, use it carefully with clean hands.

Castor oil: No clinical evidence for chemical burn recovery. It is thick, so it can seal over a wound and trap bacteria if you use it too early. Wait until the skin is fully closed.

Tea tree oil (diluted): Its antimicrobial properties are well documented, and preventing infection during healing is genuinely useful. But it has to be diluted to 1 to 3% in a carrier oil before it touches skin. Undiluted, it causes chemical irritation that worsens a compromised scalp.

Rosemary oil: Same dilution rule. Once the skin has healed, there is some evidence for circulation and follicle support ^[6]. Not for open wounds.

Essential oils for natural hair growth more broadly, including peppermint, lavender, and cedarwood, have limited but suggestive evidence for scalp circulation. The essential oils for natural hair growth guide lists the specific studies. None of these are wound-care products, so hold them until the skin has fully closed.

What to avoid: Undiluted oils of any kind on open wounds. Apple cider vinegar on broken skin (it stings and can slow healing). Coconut oil on an infected or weeping wound (its antimicrobial edge does not beat its occlusive downside there).

If you want to line up natural hair growth products for the regrowth phase, the rule is simple: wait for the wound to close, then add one product at a time so you can track what your scalp tolerates.

Will a relaxer ever be safe to use near my hairline again after a burn?

Maybe. But the bar is higher than most people expect. Dermatologists advise a minimum of 8 weeks of complete healing before any chemical service touches the previously burned area, and many push it to 12 to 16 weeks for spots that blistered or took real damage ^[3]. Even then, use a lower-strength formula, an experienced professional, and a barrier cream on the newly healed skin.

If your burn was severe enough to scar, the scar tissue does not take up chemical the way normal scalp skin does. Relaxing over scar tissue gives unpredictable results and risks re-injuring the follicles nearby.

My honest opinion: if you have burned your hairline once, that skin and those follicles have already shown they react badly to the exposure. A texturizer, a lower-pH relaxer, or stepping away from chemical straightening altogether is worth a serious look. That is not a knock on relaxers as a category. It is just risk math.

If you keep relaxing, two changes cut the risk a lot. First, do a scalp check before every application: any scratch, pimple, flaking patch, or break in the skin means postpone the service. Second, ring the hairline with base cream or petroleum jelly before application, and set a timer. Do not trust feel alone to decide when to rinse.

How do I tell a relaxer burn apart from other types of hairline damage?

A relaxer burn hits during or right after the service, with pain, redness, and possible blistering in the exact zone the chemical touched. Other hairline problems look different: traction alopecia creeps in over months with no pain, dermatitis flakes across a broader area, and postpartum shedding shows up months after birth with no skin change. The treatment path depends entirely on which one you actually have.

Relaxer chemical burn: Onset during or just after the service. Pain or burning. Redness, possible blistering. Hair in the burned zone sheds within days to weeks as the damaged strands fall.

Traction alopecia: Slow onset over months to years. No acute pain event. The hairline recedes bit by bit, often starting with the finest baby hairs vanishing. The skin looks normal. Caused by repeated tension from tight styles. See edges hair for a fuller comparison.

Seborrheic dermatitis or scalp psoriasis: Flaking, itching, and redness, but not pinned to one burn site. Usually a broader pattern across the scalp. No injury event.

Contact dermatitis from a product: An allergic or irritant reaction that can show up 24 to 72 hours after use. Redness, itching, sometimes hives or scaling. Milder than a true alkali burn, and a different thing entirely.

Postpartum hairline shedding: Starts 2 to 4 months after delivery, no skin changes, just shedding, no pain. The postpartum hair loss page covers it on its own.

A dermatologist can sort these out with a physical exam plus dermoscopy or a biopsy if needed. The right diagnosis matters because the treatments do not overlap. An antifungal for seborrheic dermatitis does nothing for a chemical burn, and a steroid cream for a burn will not fix traction damage.

What can a dermatologist do that I cannot do at home for a relaxer burn?

Plenty, and it is worth naming exactly what a clinic visit adds: an accurate burn-depth diagnosis, prescription-strength steroids, antibiotics if infection sets in, and biopsy or dermoscopy to tell recoverable loss from permanent loss. Those are the tools you simply cannot run at your bathroom sink.

Wound depth assessment. A trained clinician can grade the burn (first, second, or third degree) and judge whether follicles are still viable. That single call shapes every decision after it.

Prescription-strength topical steroids. Over-the-counter 1% hydrocortisone is fine for mild cases. Second-degree burns often need 0.05% to 0.1% clobetasol propionate or a similar high-potency corticosteroid to shut down the inflammatory cascade before it scars. That takes a prescription ^[4].

Antibiotics if infection develops. Burned scalp skin is an open door for bacteria, especially Staph aureus. A dermatologist can culture a suspicious wound and prescribe the right antibiotic, topical or oral, instead of guessing.

Platelet-rich plasma (PRP) injections. Some dermatologists offer PRP for post-inflammatory hair loss off-label. The evidence for PRP in alopecia is mixed but trending positive in small trials ^[9]. It is not first-line and most insurance will not cover it.

Scalp biopsy. If regrowth has not shown by 4 to 6 months post-burn, a punch biopsy (usually 4 mm) tells you whether follicles are still present and what tissue surrounds them. This is the only definitive way to separate recoverable loss from permanent loss.

Dermoscopy. A handheld dermatoscope shows follicular openings, scaling patterns, and vascular structures, which can tell the clinician whether follicles are still active without cutting anything.

Cost a barrier? Federally Qualified Health Centers across the United States offer medical services on a sliding-scale fee. Find one through the HRSA health center finder ^[10].

Frequently asked questions

How soon after a relaxer burn should I wash my hair?

Rinse the burned area right away with cool water for 15 to 20 minutes to flush the chemical. You can gently wash the rest of your hair the same day if you need to, but keep shampoo and product off the burned hairline until the skin starts to close, which is usually 5 to 10 days for a mild burn.

Can I use minoxidil on my hairline after a relaxer burn?

Not on broken skin. Minoxidil, in both 2% and 5%, belongs only on intact, healed scalp. On an open or blistered wound it stings hard and can make the tissue damage worse. Once the skin has fully closed and a dermatologist confirms follicles are still present, minoxidil is a reasonable option with real clinical backing for non-scarring hair loss.

What does a mild versus severe hairline relaxer burn look like?

A mild burn shows redness and tenderness that fade within hours, with no blistering. Moderate burns produce blisters, oozing, and pain that lasts more than an hour after rinsing. Severe burns involve skin that looks white, gray, or darkened, possible numbness, and wounds that take more than four weeks to close. Moderate and severe burns need professional evaluation.

How do I stop the itching on my scalp while the burn heals?

Itching during healing signals tissue repair, which is good, but scratching can tear the new skin and let infection in. A cold compress held gently for 10 minutes eases the itch without damaging tissue. Over-the-counter 1% hydrocortisone helps for a few days. Oral antihistamines like cetirizine or loratadine cut the itch signal systemically without touching the wound.

Is it normal for the skin to peel or flake after a relaxer burn on the hairline?

Yes. Peeling and flaking usually start 3 to 7 days after a mild to moderate burn as the skin sheds its damaged outer layers. Do not pick or pull at it. Let it shed on its own. If the flaking comes with oozing, spreading redness, warmth, or a foul smell, those point to infection and need a prompt medical check.

Can I put Vaseline or petroleum jelly on a relaxer burn?

Yes, once the wound is no longer actively weeping. Petroleum jelly keeps the wound moist, which speeds healing compared to letting it dry out. A thin layer after gently cleansing the area is standard wound care. Do not apply it to a wound still oozing pus or showing signs of infection, and never before you have fully rinsed off the chemical.

How long should I wait before getting another relaxer after a hairline burn?

A minimum of 8 weeks after full skin closure for mild burns. Most dermatologists recommend 12 to 16 weeks if there was blistering or any scarring. Never relax over skin that is still healing. Even after the wait, put a barrier cream on the previously burned hairline before any chemical service and use a lower-strength formula if you can.

Does hyperpigmentation on the hairline after a burn go away?

Post-inflammatory hyperpigmentation is common after any burn on darker skin and can take 6 to 18 months to fully fade. Sun protection on the hairline (yes, SPF matters there too) speeds the process. Once the wound has fully healed, dermatologists can prescribe azelaic acid, niacinamide, or low-dose hydroquinone for stubborn darkening.

What is the difference between a relaxer burn and scalp sensitivity after a relaxer?

Sensitivity is tingling, mild redness, and discomfort that clears within 30 to 60 minutes after rinsing. A burn is real tissue injury: pain that climbs instead of fading, skin color change, blistering, or symptoms that hang on for hours after the chemical is gone. Sensitivity does no lasting damage. A burn can. The tell is pain that worsens after rinsing.

Can I wear a wig while my hairline is healing from a relaxer burn?

Yes, with care. Pick a wig with an adjustable band that sits behind the burned zone rather than on top of it. Keep adhesive glues, tape, and bonding agents off healing skin entirely. A wig on a loose cap that never touches the burned area is a safe protective option, and it also keeps you from touching or scratching the wound.

Will my edges grow back thinner after a chemical burn?

If the burn was mild and the follicles survived, new hair may come in slightly finer at first and then return to its original texture over two to three growth cycles. If follicles were partly damaged, the returning hair can stay permanently finer. If the area fully scarred, no hair grows back. A dermatologist can tell you which case you are in through an exam or biopsy.

Are there any FDA-approved treatments for hair loss caused by a chemical burn?

Minoxidil is the only FDA-approved topical drug for hair loss (androgenetic alopecia) and is often used off-label for other non-scarring conditions, including post-inflammatory loss from chemical burns ^[12]. There is no FDA-approved treatment specifically for chemical-burn alopecia. Prescription corticosteroids are used off-label to limit scarring, and hair transplantation is an option for stable scarring alopecia after one to two inflammation-free years.

How can I tell if my relaxer burn has become infected?

Signs of infection include redness that spreads past the original wound, warmth, swelling, yellow or green discharge, a bad smell, or fever. If you have any of these, see a doctor the same day. An infected scalp wound can spread to nearby tissue fast and makes hair loss in the area far more likely to become permanent.

Sources

1. National Institutes of Health, National Library of Medicine: Sodium hydroxide chemical properties and alkali burn mechanism: Sodium hydroxide (lye) relaxers operate at pH 12 to 14; guanidine no-lye relaxers at approximately pH 9 to 11, both capable of causing liquefactive necrosis on prolonged skin contact
2. National Institutes of Health, MedlinePlus: Chemical burns first aid: Alkali burns cause liquefactive necrosis and should be rinsed with cool running water for 15 to 20 minutes as first aid; heat can drive chemical deeper into tissue
3. American Academy of Dermatology Association: Scarring alopecia overview: Blistering scalp burns require professional evaluation due to risk of scarring (cicatricial) alopecia; scarring alopecias affect an estimated 3% of hair loss patients seen in North American dermatology practices; scalp biopsy is needed to confirm follicular viability
4. National Institutes of Health, National Library of Medicine: Wound healing and topical corticosteroid therapy: Moist wound healing with petrolatum-based barriers promotes faster epithelialization than dry healing; topical corticosteroids applied early reduce the inflammatory response that leads to dermal scarring
5. National Institutes of Health, National Library of Medicine: Minoxidil for hair loss, randomized controlled trial evidence: Topical minoxidil 2% and 5% have evidence from multiple randomized controlled trials for stimulating hair regrowth in non-scarring alopecia conditions
6. Panahi Y et al., SKINmed Journal 2015: Rosemary oil vs 2% minoxidil for androgenetic alopecia: A 2015 randomized controlled trial found rosemary oil performed comparably to 2% minoxidil for androgenetic alopecia hair count at 6 months
7. National Institutes of Health, Office of Dietary Supplements: Biotin fact sheet: Evidence for biotin supplementation improving hair regrowth in individuals without biotin deficiency is weak; biotin deficiency itself is rare in the general population
8. Maenthaisong R et al., Journal of Ethnopharmacology 2007: Aloe vera for burn wound healing: A 2007 review found aloe vera accelerated wound healing time in first and second-degree burns compared to conventional dressings across multiple trials
9. National Institutes of Health, National Library of Medicine: Platelet-rich plasma for alopecia, systematic review: PRP injections for alopecia show mixed but trending positive results in small trials; evidence base is not sufficient to establish it as a first-line treatment
10. Health Resources and Services Administration (HRSA): Find a health center: Federally Qualified Health Centers across the United States provide medical services on a sliding-scale fee basis
11. National Institutes of Health, National Library of Medicine: Hair follicle anatomy, bulge stem cells, and scarring alopecia pathology: Follicular stem cells in the bulge region sit approximately 1.5 mm below the scalp surface; destruction of this zone by chemical or thermal injury results in irreversible follicle loss and scarring alopecia
12. U.S. Food and Drug Administration: Minoxidil OTC drug approval: Minoxidil is the only FDA-approved topical drug for hair loss (androgenetic alopecia); use in other hair loss types is off-label