Androgenetic alopecia (also called pattern hair loss) is the most common cause of gradual thinning on the scalp. It happens when genetically sensitive follicles slowly shrink over time (a process called miniaturization). The result is thinner, shorter hairs—usually around the temples and crown in men, and along the midline part in women.
Medical note: This article is for general education. It is not a substitute for medical diagnosis or personal treatment advice. If you’re unsure what type of hair loss you have, start here: Hair Loss (Complete Guide).
Quick navigation
- What it is (in plain English)
- How it looks in men vs women
- Why it happens
- How to tell if it’s pattern hair loss
- Treatments that actually help
- Timeline & what to realistically expect
- When to see a doctor
- FAQ
- References
What is androgenetic alopecia?
Androgenetic alopecia (AGA) is a genetically influenced, hormone-sensitive pattern of hair thinning that can start any time after puberty. Follicles are usually still present (so it’s non-scarring), but they gradually produce finer hairs over time.
On our site, this condition sits under: Non-Scarring Alopecia (Overview) and the bigger roadmap: Types of Hair Loss.
How it looks in men vs women
| Pattern | Typical look | Common first areas |
|---|---|---|
| Male pattern hair loss (MPHL) | Receding temples + thinning crown (vertex); may slowly connect | Frontotemporal hairline, crown |
| Female pattern hair loss (FPHL) | Widening midline part + diffuse thinning on the crown; hairline often preserved | Central scalp / part line |
Important: Women can sometimes lose hair in a “male-like” pattern, but this is uncommon and may suggest higher androgen activity—especially if there are signs like acne, irregular periods, or excess facial/body hair.
Why does it happen?
AGA is driven by a combination of:
- Genetics: inherited sensitivity of certain scalp follicles.
- Androgen signaling (especially in men): in genetically sensitive follicles, androgen activity contributes to progressive miniaturization.
- Aging biology: hair diameter and growth cycle changes can become more noticeable over time.
This is why two people with “normal” hormone levels can look very different: what matters is follicle sensitivity, not just hormone level alone.
How to tell if it’s pattern hair loss (and not something else)
Many hair-loss conditions can look similar. Start with the fastest clarity step:
Shedding vs Breakage (Practical)
Common clues that point toward AGA
- Gradual thinning over months/years (not sudden).
- Patterned distribution (temples/crown in men; central part/crown in women).
- Miniaturization signs: hairs look finer; ponytail thickness decreases; scalp shows more easily under bright light.
- Family history (not required, but common).
Clues that suggest another diagnosis (or a second problem)
- Sudden, heavy shedding after stress/illness/childbirth → may be telogen effluvium.
- Patchy bald spots → could be alopecia areata, tinea capitis, traction, etc.
- Itching, burning, pain, pus, heavy scale → evaluate promptly (possible inflammatory/scarring causes).
- Shiny smooth areas with loss of follicle openings → concern for scarring alopecia.
If you’re unsure, see: How Hair Loss Is Diagnosed and When to See a Doctor.
Treatments that actually help
There is no “instant cure,” but there are options that can slow progression and often improve density—especially when started early.
1) Topical minoxidil (men and women)
Minoxidil is one of the most widely used first-line treatments for pattern hair loss.
- Consistency matters: it must be used regularly for months.
- Early shedding can happen: some people notice temporary increased shedding early on (this can be normal).
- Ongoing use is usually required to maintain benefits.
Women: If you are pregnant, trying to become pregnant, or breastfeeding, avoid minoxidil and speak with a clinician about safer options.
2) Finasteride (primarily for men; prescription)
Finasteride is a prescription option commonly used for male pattern hair loss. It can slow progression and sometimes improve density, but it can also cause side effects. Discuss risks/benefits with a qualified clinician—especially if you have a history of mood symptoms or sexual side effects.
Women: Finasteride (and similar anti-androgen medications) may be used in select cases under specialist care, but they are not appropriate for everyone and require medical guidance.
3) Other options you may hear about
- Low-level laser devices: some are FDA-cleared for marketing; evidence and response vary.
- PRP (platelet-rich plasma): may help some people; usually requires ongoing sessions.
- Hair transplant: can be a long-term solution for selected candidates (especially when donor hair is strong).
- Camouflage: hair fibers, styling, scalp powders, and strategic haircuts can make a major visual difference.
We will cover these in more detail in: Treatment Overview.
Timeline & what to realistically expect
- First 2–8 weeks: some people notice extra shedding with minoxidil.
- 3–6 months: early improvement may appear (less shedding, slight thickening).
- 6–12 months: you can judge response more fairly.
- Maintenance: stopping treatment typically means losing benefits over time.
If you want a practical expectations framework, see: Prognosis & Expectations.
When to see a doctor (don’t wait for these)
Make an appointment promptly if you have any of the following:
- Scalp pain, burning, or tenderness
- Pus, open sores, or thick crusting
- Fast, sudden hair loss over weeks
- Shiny smooth patches or concern for scarring
- A child with patchy hair loss + scale (possible infection)
Read: When to See a Doctor
FAQ
Can androgenetic alopecia grow back?
Many people can improve density (and slow progression), especially when starting early. Full restoration is less common, and results vary.
How do I know it’s not telogen effluvium?
Telogen effluvium often causes more sudden, diffuse shedding after a trigger. AGA is typically more gradual and patterned. It’s also possible to have both at the same time. See: Telogen Effluvium (Hair Shedding).
How long should I try minoxidil before deciding it doesn’t work?
Hair grows slowly. A fair trial is usually 6–12 months of consistent use.
Do I need blood tests for pattern hair loss?
Not always. Tests are more likely when shedding is sudden/diffuse, symptoms suggest deficiency or thyroid problems, or when there are signs of hormone imbalance. See: Blood Tests & Workup.
Is finasteride safe?
Finasteride can be effective, but it can also cause side effects. A clinician should help you weigh the benefits and risks based on your health profile and preferences.
References (trusted medical sources)
- American Academy of Dermatology (AAD): Male pattern hair loss treatment
- AAD: Female pattern hair loss
- DermNet: Male pattern hair loss
- DermNet: Female pattern hair loss
- NCBI Bookshelf (StatPearls): Androgenetic Alopecia
- British Association of Dermatologists: Female pattern hair loss (patient leaflet)
Last updated: January 28, 2026.
