The Complete Guide to Hair Loss — Types, Causes, and Every Treatment Option

Medically reviewed by Dr. Dan Xu, M.D., CCFP — CPSO Licensed Physician and Founder & Medical Director of ID Cosmetic Clinic, Markham. Last updated June 2026.

Most people meet hair loss with a trip to the pharmacy or a shrug toward “genetics.” Both reactions skip the one fact that decides whether treatment will work: hair loss is not a single disease — it is the visible end-point of several distinct conditions, each with its own cause and its own treatment path. Androgenetic hair loss needs DHT blocked or follicles stimulated; telogen shedding needs its trigger found and fixed; scarring alopecia destroys follicles permanently and is a race against time. Choose the wrong approach and you waste months — sometimes the very months when intervention would have mattered most. This guide, written for patients in the Greater Toronto Area, lays out the full picture so you can make an informed decision instead of a hopeful guess.

The 5 main types of hair loss at a glance

This article is general information, not medical advice. An accurate diagnosis requires an in-person examination.

Why hair loss is more complicated than it looks

Hair loss is extremely common. Roughly half of men show noticeable thinning by age 50, and a large share of women experience meaningful hair loss at some point in life. Because it is so common, it is also widely misunderstood — and the biggest mistake is assuming all hair loss is the same problem. It isn’t. A woman shedding handfuls three months after giving birth, a man whose hairline is creeping back in an “M” shape, and a person with a smooth round bald patch overnight all have hair loss, but almost nothing else in common. They need three different work-ups and three different treatments. That is why a real diagnosis — not a guess from a photo — comes before any product or procedure.

The 5 main types of hair loss

Identifying the type correctly is the starting point for everything that follows. Here are the five you are most likely to encounter, with the mechanism and tell-tale signs of each.

1. Androgenetic alopecia (pattern hair loss)

By far the most common type — the large majority of all hair loss. The driver is DHT (dihydrotestosterone), a hormone converted from testosterone by the enzyme 5-alpha reductase. In follicles that carry the inherited sensitivity, DHT is toxic: it gradually miniaturizes the follicle, shortening each growth cycle so hairs come back finer and shorter until the follicle stops producing visible hair at all.

In men, this typically shows as a receding “M”-shaped hairline or thinning at the crown (the Hamilton–Norwood pattern). In women — partly protected by estrogen — it more often appears as diffuse thinning across the top of the scalp with the frontal hairline preserved (the Ludwig pattern), which is why female pattern hair loss is so often mistaken for “just getting older.” The key fact: androgenetic alopecia is progressive. Untreated, it only advances — but early, evidence-based treatment can slow it markedly and partially reverse it. The earlier you start, the more follicles you keep.

2. Telogen effluvium

The second most common type — a diffuse, sudden shed that follows a major stressor. Normally most scalp hairs are in the growth (anagen) phase, with only 10–15% resting (telogen). A significant shock to the body can push large numbers of growing follicles prematurely into the resting phase; two to three months later they shed together, and you suddenly see far more hair in the shower and on the pillow.

Common triggers include major surgery or serious illness, post-pregnancy hormonal shifts (postpartum hair loss is the classic example), crash dieting or low protein intake, chronic psychological stress, and abnormal iron (ferritin) or thyroid levels. The good news: telogen effluvium is usually reversible, and most people recover within 3–6 months once the trigger is gone. The catch is diagnosis — if a low ferritin is never found and corrected, the shedding simply continues.

3. Alopecia areata

An autoimmune condition in which the immune system mistakenly attacks the follicle. It shows as sharply defined round or oval bald patches on the scalp (or in the brows, lashes or beard), usually with smooth, non-inflamed skin. In severe forms it can progress to total scalp hair loss (alopecia totalis) or loss of all body hair (alopecia universalis).

Alopecia areata is unpredictable: some patches regrow on their own, others persist or recur. Treatment options include topical or intralesional corticosteroids, contact immunotherapy, and the newer class of JAK inhibitors. Because the course varies so widely, this is a type to bring to a physician rather than self-treat.

4. Traction alopecia

Physical hair loss caused by sustained mechanical pulling. Tight braids, buns, hair extensions, or frequent high-heat styling place constant tension on follicles, especially along the hairline and temples. Early signs are small broken hairs at the margins, sometimes with scalp tenderness.

Caught early, traction alopecia is reversible — change the styling habit and the follicles recover. Ignored long enough, the repeated trauma scars the follicle permanently, at which point it converts to scarring alopecia and becomes irreversible. This is one of the few hair loss types you can largely prevent yourself.

5. Scarring (cicatricial) alopecia

The type that most demands early intervention, because the damage cannot be undone. Scarring alopecia is an umbrella for destructive inflammatory conditions — lichen planopilaris, frontal fibrosing alopecia and others — in which inflammation destroys the follicle and replaces it with fibrous scar tissue, erasing its ability to regrow.

Signs vary by the specific disease but often include redness, scaling, the disappearance of follicular openings (a key clue), and active inflammation at the edges of bald areas. Once a follicle is replaced by scar, no treatment will bring that hair back. The goal therefore is not to “regrow” lost hair but to control the inflammation early and stop further destruction — which is exactly why anyone with these signs should see a doctor quickly.

How hair loss is diagnosed

Accurate diagnosis can’t be made on appearance alone. A thorough work-up usually combines several layers.

Clinical history and examination

A physician will ask when the loss began, how fast it’s progressing, whether it’s patchy or diffuse, your family history, recent major life events, medications, and diet. This history alone often points strongly toward the type before any test is run.

Blood tests

Telogen effluvium — and some cases of pattern hair loss — can hide a systemic cause. Blood work screens for it. Useful markers include:

• Ferritin (iron stores): even with normal hemoglobin, low ferritin can drive shedding; risk rises notably below about 70 ng/mL.
• Thyroid function (TSH, T3, T4): both under- and over-active thyroid can cause diffuse loss.
• Androgens (testosterone, DHEA-S, DHT): particularly relevant in women suspected of androgenetic hair loss.
• Vitamin D, zinc and related nutrients: significant deficiency can affect hair health.

Trichoscopy (scalp dermoscopy)

Trichoscopy is a non-invasive, high-magnification look at the scalp that lets a physician assess what the naked eye can’t:

• Follicular density — how many follicles remain per unit area.
• Degree of miniaturization — the ratio of fine “vellus” hairs to thick terminal hairs, a hallmark of androgenetic alopecia.
• Follicular openings — their disappearance is a key sign of scarring alopecia.
• Signs of inflammation — redness and scaling patterns.

Trichoscopy can flag follicle changes early, before thinning is obvious to the eye — which means earlier, more effective intervention.

Non-surgical hair loss treatment options that work

For most types — especially androgenetic alopecia and telogen effluvium — non-surgical treatment is the first-line and effective approach. Below are the main evidence-supported options used in a medical setting, followed by a tier table to show where each fits.

Topical minoxidil

Minoxidil is one of the few topical medications proven for hair loss and the most widely used. It works mainly by widening scalp blood vessels, improving follicular blood supply, and directly extending the hair growth phase. Women are generally advised a 2% concentration, men 5%, applied once or twice daily. Important to understand: minoxidil must be used continuously to maintain results — stop, and the hair it was supporting gradually returns to its pre-treatment state over 3–6 months. Low-dose oral minoxidil is increasingly used under medical supervision for more uniform results.

Finasteride / dutasteride (oral DHT blockers)

Finasteride inhibits type-I 5-alpha reductase to reduce DHT, blocking androgenetic alopecia at its source; dutasteride inhibits both type-I and type-II for a stronger effect. Both are first-line oral options for male pattern hair loss, taken daily, with results usually visible after 3–6 months. Women must use these with great caution: they are contraindicated in women who are pregnant or who may become pregnant because of potential effects on fetal development. Post-menopausal women may consider them carefully under a physician’s assessment. Drug treatment for female pattern hair loss should always be individualized and medically supervised.

PRP (platelet-rich plasma) for the scalp

PRP draws a small sample of your own blood, concentrates the platelets by centrifugation, and injects that plasma into target scalp zones. Activated platelets release growth factors (PDGF, VEGF, IGF, EGF and others) that stimulate follicle stem cells, help shift follicles from resting to growth phase, and improve local blood supply. Because it’s entirely autologous, allergy risk is very low. A typical starting course is 3–4 sessions spaced 4–6 weeks apart, followed by periodic maintenance.

PRF (platelet-rich fibrin)

PRF is an evolution of PRP. It uses no anticoagulant and a gentler spin, which preserves more white cells and stem-cell components and forms a natural fibrin scaffold. That scaffold acts like a slow-release capsule, letting growth factors release gradually over 1–2 weeks rather than the few hours seen with PRP. For patients who want a stronger, longer-lasting stimulus, PRF is a logical step up.

Exosome therapy

Exosomes are nanoscale vesicles secreted by stem cells, carrying mRNA, microRNA and protein signals that can directly influence how recipient cells behave. Injected into the scalp, they deliver regenerative “instructions” to follicles — promoting cell proliferation and discouraging cell death. Exosome therapy is among the most advanced options in hair restoration and is particularly useful for patients who respond poorly to PRP/PRF or who want to strengthen results.

Laser-based scalp therapy (LLLT and Nd:YAG)

Low-level laser therapy delivers specific wavelengths of light to the follicle’s mitochondria, boosting cellular energy, improving microcirculation, and extending the growth phase so more follicles stay active. Non-ablative 1064 nm Nd:YAG laser similarly improves blood flow around the follicle and adds an anti-inflammatory effect. Both are needle-free, comfortable, and often used as a base or adjunct alongside injectable therapies. They suit patients who are anxious about injections.

Why combination plans outperform any single therapy

In hair loss treatment, the limits of any one therapy are well established — and clinical experience consistently shows that combining medical and aesthetic approaches outperforms any single one. The reason is mechanistic: each tool hits a different point in the disease.

• Oral DHT blockers shut off the damage signal at its source.
• PRP / PRF / exosome injections deliver regenerative signals straight to dormant or struggling follicles.
• Laser therapy (LLLT / Nd:YAG) improves scalp microcirculation, creating a better growth environment.
• Topical minoxidil keeps blood vessels dilated for ongoing nourishment.

Used together, these cover several targets at once — blocking damage, delivering nutrients, activating regeneration, and maintaining the environment — where a single therapy reaches only one or two. A common plan for moderate androgenetic alopecia might combine monthly PRP or PRF (an initial course of 3–4) with regular laser sessions, daily topical minoxidil, and oral finasteride where appropriate. There is no universal formula: a combination plan must be built by a physician around your specific type, severity, health and goals.

Realistic expectations — and why timing matters most

Honest expectations are part of good treatment. Non-surgical therapy is excellent at keeping and reactivating follicles that still function; it cannot resurrect a follicle that has fully scarred over or completely miniaturized away. Results take months, not weeks, because hair grows on a slow cycle — most patients judge progress at the 4–6 month mark and beyond, not after one session.

Timing often matters more than the choice of treatment. Because miniaturization in androgenetic alopecia is gradual, the earlier you intervene, the more functional follicles you can preserve and activate, and the better the outcome. When loss is already advanced and many follicles have fully shrunk, even the strongest combination plan can mostly hold the line rather than dramatically reverse it. That is the real reason physicians repeat the same advice: if you’re noticing hair loss, get it assessed sooner rather than later. Pricing varies by plan and number of sessions and is best confirmed at consultation (from Quoted at consultation).

Who should be cautious — and when to see a doctor fast

Most non-surgical hair treatments are well tolerated, but candidacy still matters. Tell your physician if you are pregnant or breastfeeding (oral DHT blockers are contraindicated, and any plan needs review), if you have a bleeding disorder or take blood thinners (relevant to injectable therapies), if you have an active scalp infection or inflammatory skin condition, or if you take medications that affect immunity or healing. Certain signs warrant prompt medical attention rather than at-home products: sudden patchy loss, a rapidly advancing bald spot, scalp redness, scaling, pain, or the loss of follicular openings — these can signal alopecia areata or scarring alopecia, where early treatment changes the outcome. This article is general information, not medical advice; an accurate diagnosis and plan require an in-person assessment.

The real takeaway

The most expensive mistake in hair loss is treating the wrong condition. Get the diagnosis right first — type, cause, and how far it has progressed — and the treatment path becomes clear and far more likely to work. For the common, progressive types, modern non-surgical options used in combination can genuinely preserve and improve your hair, but they reward early action. The follicles you keep are the ones you act on in time.

Frequently asked questions

What are the main types of hair loss?

The five most common are androgenetic alopecia (male or female pattern, driven by DHT), telogen effluvium (stress or post-pregnancy shedding), alopecia areata (autoimmune patches), traction alopecia (from tight styling), and scarring alopecia (permanent inflammatory damage). Each has a different cause and a different treatment, so accurate diagnosis comes first.

Is female pattern hair loss treated the same way as male hair loss?

Not entirely. Female hair loss has more possible causes, so a work-up also screens for thyroid problems, iron-deficiency anemia and post-pregnancy hormonal shifts. Women generally don’t use finasteride (it can affect hormones and is unsafe in pregnancy), and the minoxidil concentration for women (2%) is lower than for men (5%). PRP, PRF and exosome therapy work for both sexes without sex-specific side effects.

Will my hair fall out again if I stop minoxidil?

Yes. Once you stop minoxidil, the hair it was supporting gradually returns to its pre-treatment state over 3–6 months, because minoxidil works by dilating vessels and extending the growth phase — effects that stop when the drug stops. Androgenetic alopecia therefore needs ongoing maintenance, not a one-and-done course.

How long until hair loss becomes permanent?

It depends on the type. Androgenetic alopecia is gradual — follicles miniaturize over time, so the earlier you treat, the more you keep. Telogen effluvium usually recovers within 3–6 months once the trigger is fixed. Scarring alopecia is permanent once scar forms. Alopecia areata can self-resolve or need treatment. There’s no single number — the priority is an early diagnosis to identify the type.

Does PRP actually work for hair loss?

For appropriate candidates — especially early to moderate androgenetic alopecia and diffuse thinning — PRP can stimulate follicles and improve density. It uses your own blood’s growth factors, so allergy risk is very low. It works best as a course of 3–4 sessions plus maintenance, and is most effective combined with other therapies rather than used alone.

What’s the difference between PRP and PRF?

PRF is a refinement of PRP. It uses no anticoagulant and a gentler spin, preserving more cells and forming a fibrin scaffold that releases growth factors slowly over 1–2 weeks instead of a few hours. That makes PRF a stronger, longer-acting option for patients who want more from each session.

Can hair loss be reversed naturally?

Some types improve once the underlying cause is corrected — for example, telogen effluvium often recovers after low iron, thyroid issues, crash dieting or major stress are addressed. Androgenetic alopecia, however, won’t reverse on its own; it’s progressive and needs active treatment. Scarring alopecia cannot be reversed at all. This is why identifying the type matters before relying on “natural” measures.

Is hair loss treatment painful or does it require downtime?

Most non-surgical options involve little to minimal downtime. Laser and topical treatments are needle-free and comfortable. Injectable therapies like PRP, PRF and exosomes involve fine needles into the scalp with topical numbing; mild tenderness or minor swelling can occur for a day or so. You can typically return to normal activity the same day.

When should I see a doctor instead of trying products?

See a physician promptly if you notice sudden patchy loss, a rapidly spreading bald spot, or scalp redness, scaling, pain or loss of follicular openings — these can indicate alopecia areata or scarring alopecia, where early treatment protects against permanent loss. Even for common thinning, a quick assessment confirms the type so you don’t spend months on the wrong product.

Related treatment: PRP hair loss treatment in Toronto — assessed and performed by Dr. Dan Xu, MD, CCFP at ID Cosmetic Clinic in Markham.

Related at ID Cosmetic Clinic

• Treatment: PRP & PRF Hair Restoration
• Treatment: Exosome & Laser Hair Therapy
• Condition: Androgenetic Alopecia (Pattern Hair Loss)
• Condition: Telogen Effluvium (Diffuse Shedding)
• Compare: PRP vs PRF for Hair: What’s the Difference?
• Read next: Postpartum Hair Loss: What’s Normal and What to Do