Can Testosterone Cause Hair Loss?

Testosterone gets blamed for a lot—aggression, acne, hair loss. The truth is messier. If you’re seeing more scalp in the mirror or shedding on your pillow, you want a straight answer: does testosterone actually make you lose hair, and what can you do about it? I’ve coached hundreds of readers and clients through this question, often in tight coordination with dermatologists and endocrinologists. The short version: testosterone doesn’t “make” you go bald by itself. Genetics plus a potent testosterone byproduct called DHT drive most pattern hair loss. The longer version—and the one that will help you protect your hair—lives below.

The kind of hair loss we’re really talking about

Most people asking about testosterone are dealing with androgenetic alopecia (AGA)—better known as male pattern baldness or female pattern hair thinning. It’s extremely common: roughly 50% of men by age 50 and about 40% of women by midlife experience some version of it. Men tend to see a receding hairline and thinning at the crown. Women usually notice a widening part and diffuse thinning on the top while maintaining their frontal hairline.

AGA is different from:

• Telogen effluvium: a temporary shed often triggered by stress, illness, crash dieting, childbirth, or medication changes.

• Alopecia areata: patchy, autoimmune-driven hair loss.

• Traction alopecia: from tight hairstyles or chronic tension.

• Scalp disorders like seborrheic dermatitis or psoriasis that can worsen shedding.

Why this matters: you don’t treat these the same way. And not all of them have anything to do with testosterone.

A quick refresher on the hair cycle helps explain what you’re seeing. Around 85–90% of scalp hairs sit in a growth phase (anagen) that lasts 2–6 years. A brief transitional phase follows (catagen), then a resting phase (telogen) of roughly 2–3 months before the hair sheds and the follicle cycles again. Daily shedding of 50–100 hairs is normal. In AGA, the growth phase shortens and each follicle produces progressively thinner, shorter “miniaturized” hairs.

Testosterone, DHT, and your hair follicles

Here’s what’s happening biochemically.

• Testosterone converts to dihydrotestosterone (DHT) via the enzyme 5-alpha-reductase (5-AR). There are two main 5-AR types in humans: type I (more in skin and sebaceous glands) and type II (dense in hair follicles and prostate).

• DHT is more potent than testosterone at the androgen receptor. In genetically susceptible follicles—especially those on the temples and crown—DHT gradually shrinks the hair follicle, producing thinner hairs and shorter growth cycles. Over time, follicles can go dormant.

• The key is sensitivity, not just hormone levels. Androgen receptor density and 5-AR activity vary from person to person and even scalp to scalp. Genetics (including variants in the AR gene on the X chromosome and in 5-AR genes) load the dice.

That’s why two brothers with similar testosterone levels can have different hairlines—and why someone with normal testosterone can thin while another with high-normal levels keeps a full head of hair.

So, does higher testosterone cause hair loss?

Not in a simple, direct way. Several lines of evidence point to DHT and follicular sensitivity as the real drivers:

• Studies have not found a consistent, strong correlation between serum testosterone levels and male pattern hair loss. Many balding men have normal testosterone. Plenty of non-bald men have high-normal testosterone.

• Local (scalp) DHT activity matters more than what’s circulating in your blood. Follicles behave based on what happens in their microenvironment.

• Meanwhile, when DHT is suppressed, hair loss often slows or stabilizes. That’s the mechanism behind drugs like finasteride and dutasteride.

• In women, conditions with elevated androgens (e.g., polycystic ovary syndrome) can contribute to female pattern hair loss, but estrogen, insulin resistance, and genetic factors interplay as well.

Think of testosterone as a precursor. Without it, you can’t make DHT. But the presence of testosterone doesn’t doom you to hair loss unless your follicles are genetically set to overreact to DHT.

What about TRT—does testosterone replacement therapy trigger shedding?

Testosterone therapy can unmask or accelerate hair loss in people who are already predisposed to AGA. I see this most often in men who start TRT in their 30s or 40s and notice increased temple recession or crown thinning over the next 3–12 months. Why it happens:

• TRT raises circulating testosterone, and some of that converts to DHT. Depending on your baseline sensitivity, that bump can speed up miniaturization.

• Formulation can matter. Transdermal gels may increase DHT more in skin due to local 5-AR activity. Injections can cause peaks and troughs that some people feel as shedding waves. Pellets deliver steady exposure over months. None is “right” for everyone.

• Genetics still rule. In clinical trials, alopecia appears as an adverse event in a minority (often single-digit percentages), but in real-world practice, men with early pattern loss or family history are much more likely to notice a change.

A common pattern is a temporary surge in shedding 2–4 months after starting TRT—sometimes a telogen effluvium triggered by the hormonal shift—followed by stabilization. If you’re susceptible to AGA, you may then notice gradual thinning in classic patterns. The silver lining: both are manageable, especially if you start a hair-preservation plan early.

Anabolic steroids: a faster, riskier story

Anabolic-androgenic steroids (AAS) used for performance or physique goals often hit hair harder than medical TRT. Two reasons:

• DHT-derivatives (e.g., stanozolol, oxandrolone, drostanolone) are already DHT-like and do not rely on 5-AR conversion. Blocking 5-AR won’t help much because the compound itself acts like DHT at the follicle.

• Stacking multiple androgens, running high doses, or stretching cycles increases exposure and accelerates miniaturization. Lots of lifters only realize their genetic susceptibility once a cycle flips the switch.

If you’ve noticed sudden shedding on an AAS cycle, reducing or stopping the androgens is step one. Everything else is secondary.

How to tell if testosterone is the culprit

You want clarity before changing therapies. Work through this checklist:

1) Map the pattern

• Receding corners and vertex thinning point toward AGA.

• Diffuse shedding without pattern after a stressor (illness, crash diet, surgery) suggests telogen effluvium.

• Patchy loss with smooth skin suggests alopecia areata.

2) Timeline it

• Did shedding start 2–4 months after beginning TRT, switching formulations, or increasing dose? That supports a hormone shift effect.

• Has thinning been slowly progressing for years? Testosterone may be incidental.

3) Review family history

• A father, mother, uncles, or grandparents with thinning increases odds of AGA.

4) Check the scalp

• Greasy scale and redness suggest seborrheic dermatitis, which can worsen shedding but is treatable.

• Miniaturized hairs (short, thin) among normal hairs indicate AGA.

5) Consider labs (with your clinician)

• Total and free testosterone, SHBG

• DHT (helpful in some cases, though not always necessary)

• Thyroid panel (TSH), ferritin (ideal often >50–70 ng/mL for hair), vitamin D, B12

• For women: androgens (DHEA-S, total and free T), prolactin, and if PCOS is suspected, metabolic markers

6) Hair-pull test and photos

• A dermatologist can do a pull test or trichoscopy to visualize miniaturization. At home, standardized photos every 2–3 months are gold for tracking.

Evidence-based ways to protect and regrow hair

If your follicles are DHT-sensitive, your strategy is to reduce that androgenic pressure and support regrowth.

5-alpha-reductase inhibitors (men; selected cases in women)

• Finasteride: Typically 1 mg daily for hair. Reduces serum DHT by about 60–70% and scalp DHT significantly. In large studies, most men halt or slow loss; a meaningful portion see regrowth over 6–12 months. Commonly reported side effects in trials are low (sexual side effects around 1–3%), but real-world reports vary. Talk candidly with your physician.

• Dutasteride: Stronger 5-AR inhibitor (blocks type I and II). 0.5 mg can reduce DHT by 90%+. Often effective in non-responders to finasteride. More potent—and off-label for hair in many countries—so medical guidance is essential.

Women of childbearing potential should not handle or take these drugs due to the risk of birth defects. Postmenopausal women under specialist care may use low-dose finasteride or dutasteride off-label in select cases.

Minoxidil (topical and low-dose oral)

• Topical: 5% foam or solution once or twice daily. Helps prolong the growth phase and enlarge miniaturized hairs. Expect visible changes after 3–6 months; full assessment at 12 months. Common side effects: scalp irritation, initial shedding as follicles synchronize.

• Low-dose oral minoxidil (LDOM): An off-label but increasingly used option. Typical doses: men 2.5–5 mg nightly; women 0.625–2.5 mg. Useful when topical is irritating or inconvenient. Side effects can include ankle swelling, increased body hair, and, rarely, changes in heart rate or blood pressure. Work with a clinician.

Minoxidil and a 5-AR inhibitor together are more effective than either alone for many men with AGA.

Anti-androgens in women

• Spironolactone: Blocks androgen receptors and reduces androgen production. Common doses range from 50–200 mg daily. It can reduce shedding and improve density in women with androgen-sensitive thinning, especially with signs of hyperandrogenism (acne, hirsutism). Requires birth control due to teratogenic risk and periodic lab monitoring.

• Oral contraceptives: Certain OCPs with low-androgenic progestins can help balance hormones and slow loss in women with hyperandrogenism.

Scalp health, shampoos, and inflammation control

• Ketoconazole 1–2% shampoo 2–3 times weekly can reduce inflammation and has mild anti-androgenic effects in the scalp. Many patients notice less itch and flaking, and some get modest thickening over time.

• Treat seborrheic dermatitis or psoriasis aggressively; unchecked inflammation worsens shedding.

Low-level laser therapy (LLLT)

FDA-cleared caps and combs can stimulate follicles and improve hair counts by a modest but real margin (think 15–25 hairs/cm² over several months in studies). It’s safe, works best for mild to moderate AGA, and can be combined with other treatments. Consistency matters: 15–30 minutes, 3–4 times a week.

Platelet-rich plasma (PRP)

PRP injections use your own platelets to deliver growth factors to the scalp. Evidence shows variable but often positive results—modest increases in hair density for responders. It’s technique-dependent and typically done in a series (e.g., monthly for 3 months, then maintenance). Great for motivated patients with early AGA and for those who can’t use 5-AR inhibitors.

Microneedling

At-home 0.5 mm rollers or in-clinic 1.0–1.5 mm sessions can stimulate growth factors and may boost the efficacy of topical minoxidil. Start weekly or biweekly. Keep it clean to avoid infection.

Nutrition and lifestyle

• Protein: Aim for roughly 0.8–1.2 g/kg/day. Hair is protein-hungry.

• Iron: Low ferritin is a frequent clue in women with shedding. Getting ferritin into the 50–70 ng/mL range can help. Supplement only with testing and guidance.

• Vitamin D and zinc: Deficiencies correlate with shedding; correct if low.

• Stress and sleep: Chronic stress can keep you in a shedding cycle. Prioritize 7–9 hours of sleep and evidence-based stress strategies (exercise, CBT skills, breathwork).

• Avoid crash dieting: Rapid weight loss is a classic telogen effluvium trigger.

If you’re on TRT: a practical game plan

Here’s how I walk TRT users through hair protection with their prescribing clinician.

1) Confirm why you’re on TRT

• True hypogonadism with symptoms and low morning testosterone on repeated tests is different from “optimization.” If you need TRT for health, protect hair rather than stopping abruptly.

2) Pick a formulation thoughtfully

• Gels can raise skin DHT more; injections can produce peaks; pellets are steady but not easily adjusted. If you notice shedding on one, a formulation change can help.

3) Start hair prevention early

• Baseline photos before TRT.

• Begin minoxidil from day one if you have a family history or early signs of AGA.

• Discuss adding finasteride (oral or topical) if you notice progression. For sensitive responders, some clinicians use low-dose dutasteride once or twice weekly.

4) Titrate testosterone and monitor

• Don’t chase supraphysiologic levels. Often, the dose that resolves symptoms sits within the reference range.

• Recheck labs and hair photos every 3–4 months during the first year.

5) Address scalp health

• Ketoconazole shampoo 2–3 times weekly; a gentle daily shampoo otherwise.

• Manage dandruff or inflammation quickly.

6) If shedding spikes

• Differentiate a transient telogen effluvium from ongoing AGA. If it’s a surge 2–4 months after a change, hold steady and give it 3 months while maintaining your hair protocol. If clear AGA progression, escalate treatment.

7) Consider the tradeoffs

• If hair health is a priority and you’re highly sensitive, a lower TRT dose or alternative regimen may strike a better balance.

Women, testosterone, and thinning

Women can lose hair in androgen-sensitive patterns, but the hormone picture is broader.

• PCOS: Elevated androgens, irregular cycles, acne, and insulin resistance frequently coexist. Treating PCOS—weight management, insulin-sensitizing strategies, appropriate OCPs—plus spironolactone and minoxidil can ease shedding.

• Postpartum: A normal telogen effluvium hits 2–4 months after delivery due to the sudden drop in hormones. It usually resolves over 6–12 months. Minoxidil and gentle scalp care help. Don’t blame testosterone here.

• Perimenopause/menopause: Declining estrogen can unmask androgen sensitivity. Minoxidil remains foundational; some postmenopausal women respond well to low-dose anti-androgens under specialist care.

• Lab targets: Aim for ferritin >50 ng/mL, replete vitamin D, and screen thyroid. I’ve seen many women improve simply by correcting low ferritin and adding minoxidil consistently.

Myths vs. facts worth clearing up

• Myth: Bald men have higher testosterone. Fact: Not reliably. Balding correlates with follicular sensitivity to DHT, not high serum testosterone.

• Myth: Hats cause hair loss. Fact: They don’t. Tugging and traction from tight styles can break hair, but hats don’t miniaturize follicles.

• Myth: Poor scalp blood flow causes AGA. Fact: Reduced blood flow is a consequence, not the cause, of miniaturization. Minoxidil’s vasodilation helps, but its main effect is prolonging anagen.

• Myth: Shaving your head makes hair grow back thicker. Fact: It looks thicker because hairs are cut bluntly, but the follicle’s biology doesn’t change.

• Myth: “DHT-blocking shampoos” will fix it. Fact: Shampoos with ketoconazole can help, but they’re supportive, not curative. If you’re miniaturizing, you need a real plan.

• Myth: Supplements alone will regrow patterned hair. Fact: If you’re deficient, correction helps. But no over-the-counter supplement rivals FDA-proven therapies for AGA.

Real-world examples

• Case 1: A 28-year-old man started a DHT-derived anabolic for eight weeks and noticed aggressive temple recession. He stopped the cycle, began 5% topical minoxidil twice daily, and adopted a weekly 1.0 mm microneedling session. Because the compound was DHT-based, finasteride alone was less helpful during the cycle, but post-cycle he added finasteride 1 mg daily. At nine months, photos showed thicker temples and a stabilized hairline.

• Case 2: A 44-year-old man with confirmed hypogonadism began TRT injections and saw a mild crown shed at month four. He didn’t want daily meds. He switched to pellets for steadier levels, used ketoconazole shampoo three times weekly, and added dutasteride 0.5 mg once weekly (off-label) plus nightly 2.5 mg oral minoxidil under his doctor’s supervision. At 12 months, density improved and shedding normalized.

• Case 3: A 35-year-old woman with PCOS had diffuse thinning and a widening part. Labs showed ferritin at 19 ng/mL and vitamin D insufficiency. Her gynecologist prescribed a low-androgenic OCP and spironolactone 100 mg/day; she added 5% minoxidil once daily, iron and vitamin D repletion, and nutrition coaching. At six months, shedding decreased, and at one year, she had noticeable part coverage.

Common mistakes that cost people their hair

• Waiting for a miracle shampoo. Shampoos help scalp health; they don’t replace DHT-targeted therapy or minoxidil.

• Starting minoxidil and quitting after a few weeks. There’s often an initial shed, which is a sign the drug is working. Give it 6–12 months.

• Self-medicating hormones. Adjusting TRT or using AAS without medical oversight is a recipe for hair and health problems.

• Ignoring scalp inflammation. Flakes, itch, and redness degrade hair quality. Treat them.

• Crash dieting. Rapid weight loss is one of the most common triggers of telogen effluvium I see.

• Mega-dosing biotin. It can interfere with lab tests (thyroid, troponin) and rarely helps unless you’re deficient. Stick to modest doses if used at all, and tell your clinician before labs.

• Waiting too long. Once follicles are slick-bald and inactive for years, regrowth is unlikely. Stabilization early is your best friend.

A step-by-step plan you can follow

If you’re a man seeing early signs: 1) Take standardized photos (front, sides, crown) in good light. 2) Start 5% minoxidil nightly. Commit for 12 months. 3) Add ketoconazole shampoo 2–3x weekly; use a gentle daily shampoo otherwise. 4) Discuss finasteride 1 mg daily with your clinician. If concerned about side effects, consider topical finasteride-minoxidil combo or a lower dose. 5) Optional: LLLT cap 3–4x/week; weekly microneedling. 6) Reassess at 6 and 12 months with photos. Adjust therapy if progression continues (e.g., consider dutasteride under medical guidance).

If you’re on TRT: 1) Document hair baseline before starting. 2) Choose a formulation with your doctor and avoid overdosing. 3) Begin minoxidil from day one if you’re high-risk (family history, early miniaturization). 4) Add a 5-AR strategy if thinning appears: finasteride daily or a lower-frequency dutasteride plan. 5) Keep ferritin, vitamin D, and thyroid optimized; treat scalp issues. 6) If shedding spikes after a change, pause new variables, take photos, and give it 8–12 weeks while staying consistent.

If you’re a woman with diffuse thinning: 1) See a dermatologist or women’s hair specialist; request ferritin, thyroid, vitamin D, and androgens if symptoms suggest PCOS. 2) Start 5% minoxidil once daily (foam often less irritating). 3) If hyperandrogenism is present, discuss OCPs and spironolactone. Ensure reliable contraception. 4) Correct nutritional gaps; prioritize protein and iron if ferritin is low. 5) Consider LLLT and microneedling as adjuncts. 6) Track progress every 3 months, aiming for a 12-month horizon.

What the data say about treatments

• Finasteride: In large, long-term studies, most men maintain or increase hair count vs. placebo, with many reporting visible improvement by 6–12 months. DHT reduction is roughly 60–70% systemically.

• Dutasteride: More potent; studies suggest greater increases in hair counts vs. finasteride for some men, likely due to broader 5-AR inhibition.

• Minoxidil: Around 40–60% of users see moderate regrowth; nearly all slow the rate of loss while on therapy. Results plateau around 12 months and require ongoing use to maintain.

• PRP: Meta-analyses show modest but significant gains in density for responders; results vary widely by protocol and provider.

• LLLT: Demonstrates increases in hair counts and thickness over 16–26 weeks; safe and synergistic with minoxidil/finasteride.

• Ketoconazole: Small studies suggest improvement in hair diameter and reduction in inflammation when used regularly.

Realistically, combining therapies yields the best outcomes. Hair biology is redundant; your plan should be too.

When to see a specialist

• Rapid shedding with patchy hair loss or eyebrow/eyelash involvement

• Sudden shedding after illness or childbirth that doesn’t improve by six months

• Burning, pain, or scarring on the scalp

• Unclear diagnosis after trying basic measures

• Considering oral therapies and wanting a tailored plan

A dermatologist with a focus on hair disorders can do trichoscopy, targeted labs, and design a regimen that fits your risk tolerance and goals.

What I tell clients who feel stuck

You can’t change your genetics, but you can absolutely change the story your follicles are living in. Most people do best with a layered approach: lower DHT in the scalp if you’re sensitive, support growth with minoxidil, keep the scalp calm, and avoid self-sabotage like crash dieting or yo-yo dosing. If you’re on TRT, get in front of the problem rather than reacting months later. And give treatments time—hair works on a slow clock.

The testosterone–hair loss link isn’t a simple cause-and-effect. It’s a triangle: hormones, genetics, and timing. Control what you can in each corner. Start tracking today. Pick one or two proven steps and stick with them for a full hair cycle. With consistency and the right plan, stabilization is very achievable, and regrowth is possible for many.