Male pattern baldness is the most common form of hair loss in men, affecting over 50 million men in the United States alone. Despite how common it is, much of what people believe about it is wrong.

This guide covers the real causes, how to identify what stage you're at, and — most importantly — what the clinical evidence says actually works.

What Is Male Pattern Baldness?

Medically known as androgenetic alopecia (AGA), male pattern baldness is a genetically predetermined condition caused by an excessive response to androgens — specifically DHT (dihydrotestosterone).

It's characterized by:

Progressive miniaturization of hair follicles
Gradual shortening of the anagen (growth) phase
Transformation of thick terminal hairs into fine vellus hairs
A predictable pattern of loss: temples, crown, and mid-scalp

The Real Causes (It's Not Just Genetics)

Genetics: The Foundation

AGA is a polygenic trait — meaning hundreds of genes contribute to your risk, not just one.

The old wives' tale says "you get baldness from your mother's side." Here's the truth:

The androgen receptor (AR) gene sits on the X chromosome (inherited from your mother)
But over 600 genetic risk variants have been identified across multiple chromosomes
Both maternal AND paternal genes contribute to your risk
Sons have 5-6x higher risk if their fathers experienced balding

Key insight: Having the genes doesn't guarantee severe baldness. Environmental and lifestyle factors often determine when and how fast hair loss progresses.

Hormones: DHT and Beyond

While DHT is the primary driver, other hormonal factors play important roles:

DHT — The Main Culprit

Produced when 5-alpha reductase converts testosterone
Binds to androgen receptors in susceptible follicles
Triggers progressive follicular miniaturization
Creates a vicious cycle with PGD2 (prostaglandin D2)

Thyroid Hormones

Both hypothyroidism and hyperthyroidism cause diffuse thinning
Even subclinical thyroid dysfunction can accelerate shedding
More common in women but affects men too

Insulin and Metabolic Health

Hyperinsulinemia increases 5-alpha reductase activity
Insulin resistance is associated with more rapid AGA progression
Metabolic syndrome accelerates balding through multiple pathways

Cortisol (Stress)

Chronic stress increases DHT production
Disrupts hair growth cycles
Creates "telogen effluvium overlay" — stress-induced shedding compounds genetic loss

Lifestyle Factors (Modifiable Risks)

A 2026 meta-analysis of 31 studies identified these risk factors:

Factor	Impact	Type
Family history	OR 2.72-4.24	Non-modifiable
Smoking	OR 1.46-1.60	Modifiable
Alcohol consumption	OR 1.72	Modifiable
Poor sleep	OR 1.36	Modifiable
Overweight/obesity	OR 2.31	Modifiable
Hypertension (men)	OR 1.60	Modifiable
Insulin resistance	SMD 0.40	Modifiable

The modifiable factors are your leverage points. While you can't change your genes, you can influence how and when they express.

Nutritional Deficiencies

Poor nutrition doesn't cause AGA, but it can significantly accelerate it:

Iron deficiency (ferritin <40 ng/mL) — The most common nutritional cause of hair shedding
Vitamin D deficiency — Hair follicles contain vitamin D receptors; deficiency disrupts cycling
Zinc deficiency — Impairs protein synthesis in the follicle
Severe protein restriction — Triggers telogen effluvium within months

Medications That Accelerate Hair Loss

Certain drugs can trigger or worsen AGA:

Beta-blockers (blood pressure)
SSRIs (antidepressants)
Isotretinoin (acne treatment)
Anabolic steroids — one of the most dramatic accelerators
Anticoagulants

The Norwood Scale: What Stage Are You?

The Norwood-Hamilton scale classifies male pattern baldness into stages:

Norwood 1 — No significant recession. Adolescent hairline.

Norwood 2 — Minor recession at the temples. Slight M-shaped hairline.

Norwood 3 — The earliest stage considered "balding." Definite recession at the temples. This is where most men first notice.

Norwood 3 Vertex — Recession at the temples PLUS thinning at the crown (vertex). Many men skip from Norwood 2 to this stage.

Norwood 4 — Significant recession at the temples and crown. A bridge of hair remains between the front and crown.

Norwood 5 — The bridge of hair between front and crown thins significantly. The two balding areas are starting to merge.

Norwood 6 — The bridge is gone. Frontal and vertex balding merge into one large area.

Norwood 7 — Most severe stage. Only a band of hair remains on the sides and back.

When to Act

Norwood 1-2: Prevention mode. Lifestyle optimization, monitoring.
Norwood 3: Early treatment. This is the optimal window for intervention.
Norwood 3-4: Active treatment. Finasteride + minoxidil combination therapy.
Norwood 5+: Treatment + possibly transplant consultation.

What Actually Works: Treatment Evidence

Tier 1: FDA-Approved, Strong Evidence

Finasteride (1mg daily)

Reduces scalp DHT by 64%
99% of men show decreased or reversed hair loss
Best for vertex and mid-scalp
Generic available for $3-15/month

Minoxidil (5% topical)

Vasodilator that enhances follicular blood supply
Stimulates PGE2 production
Available over the counter
Initial shedding is normal and expected

Tier 2: Prescription, Good Evidence

Dutasteride (0.5mg daily)

Inhibits both Type I and Type II 5-alpha reductase
More potent than finasteride
Off-label for hair loss (FDA-approved for BPH)

Topical finasteride (0.25%)

Comparable results to oral with less systemic impact
Better side effect profile

Tier 3: Emerging Treatments

Clascoterone

First new mechanism in 30 years
Topical androgen receptor antagonist
FDA-approved for acne; trials ongoing for AGA

Low-level laser therapy (LLLT)

FDA-cleared devices available for home use
Modest evidence for mild to moderate thinning

PRP (Platelet-Rich Plasma)

Growth factors delivered to the scalp
Variable results; multiple sessions required
Cost: $500-1500 per session

Tier 4: Supportive (Limited Evidence)

Nutritional supplementation (iron, vitamin D, zinc, biotin)
Ketoconazole shampoo (mild anti-androgenic effect)
Microneedling (may enhance topical absorption)
Stress management and sleep optimization

The Cardiovascular Connection

An often-overlooked aspect: AGA is increasingly identified as a risk factor for cardiovascular disease, especially when it manifests early or involves vertex loss. Associated conditions include:

Hypertension
Insulin resistance
Abnormal lipid profiles
Increased risk of myocardial infarction

This doesn't mean baldness causes heart disease — rather, they share common underlying factors (androgens, metabolic dysfunction, inflammation). Men with early AGA should be screened for cardiovascular risk factors.

The Bottom Line

Male pattern baldness is caused by a combination of genetic sensitivity to DHT and modifiable lifestyle factors. The Norwood scale helps you identify your stage and determine the right treatment approach.

The evidence is clear: early intervention yields the best results. Finasteride and minoxidil remain the cornerstone treatments, with combination therapy outperforming either alone.

Don't fall for supplements, shampoos, or miracle cures that lack clinical evidence. And don't wait — once follicles fully atrophy, the loss is irreversible.

Consult with a qualified healthcare provider for personalized treatment recommendations.

Male Pattern Baldness: Causes, Stages, and What Actually Works