The 5 real causes of male hair loss, and why only 1 is genetic.

Published by the Health Desk Hair Loss Updated September 4, 2026 11 min read

A clinician in a white coat parting a man's thinning hair to examine his scalp — Pattern matters more than volume. Where the hair is thinning is usually the first clue to which cause is driving it.

The other four are things you can influence, and they are often the ones quietly doing the most damage. Here is what is actually thinning your hair, and what helps each cause.

It is normal to shed some hair every day. Most people lose up to 100 hairs daily as part of the natural growth cycle, and this usually goes unnoticed.¹ Hair loss becomes a concern when shedding outpaces regrowth, or when the hair begins to thin in a recognizable pattern.

In men, the most common single reason is androgenetic alopecia, often called male pattern baldness. But it is rarely the whole story. More than one factor is usually at work, and the causes that can actually be treated are often ignored in favor of the one that cannot. Below are the five most common causes of hair loss in men, how each affects the follicle, and what helps.

1. Genetics and DHTAndrogenetic alopecia

Cross-section of a hair follicle surrounded by DHT molecules clustered around the root — DHT collecting around the root. With each growth cycle the follicle it feeds gets a little smaller. Illustration, not a photograph.

Androgenetic alopecia is the most common cause of hair loss in men and affects up to half of men over the course of a lifetime.² It is driven by dihydrotestosterone (DHT), a hormone the body makes from testosterone. In men whose follicles are genetically sensitive to it, DHT binds to the follicle and gradually shrinks it, a process called miniaturization. With each cycle the hair returns finer and shorter, until the follicle stops producing visible hair.

Signs: a receding hairline, thinning at the crown, or both.

What helps

Reducing DHT's effect on the follicle. Oral finasteride lowers DHT throughout the body and is effective, but it requires a prescription and carries a risk of sexual and mood-related side effects for some men.³ Saw palmetto, a plant extract, has been studied for a similar effect on the enzyme that makes DHT, applied locally at the scalp rather than taken as a pill.⁴

2. Reduced scalp blood flowPoor microcirculation

Cross-section of a dull, undernourished follicle fed by thin capillaries carrying scattered oxygen molecules — A follicle on a thin blood supply. It keeps producing hair, but finer and weaker hair. Illustration, not a photograph.

Hair follicles depend on a steady supply of oxygen and nutrients delivered through small blood vessels in the scalp. When circulation drops, follicles receive less of what they need and tend to produce thinner, weaker strands. Poor blood flow rarely starts hair loss on its own, but it accelerates it.

What helps

Improving blood flow to the follicle. Minoxidil, the most common topical treatment, works largely by widening blood vessels, though it does not work for everyone; studies suggest only about 3 to 4 in 10 men respond, in part because it must be activated by a scalp enzyme not everyone produces.⁵ Rosemary and caffeine have also been studied for their effect on scalp circulation and hair growth.⁶

3. Chronic scalp inflammationPerifollicular inflammation

Cross-section of a follicle encased in hardened, thickened grey tissue — Inflamed tissue thickening around the follicle. This is the change that makes recovery harder, and it is usually invisible from the outside. Illustration, not a photograph.

Low-grade inflammation around the follicle, sometimes linked to conditions such as seborrheic dermatitis, can speed up hair loss. Persistent inflammation changes the surrounding tissue in ways that make it harder for the follicle to recover, and it is often present without obvious symptoms.

Signs: itching, flaking, or redness, although inflammation is frequently not visible.

What helps

Calming scalp inflammation. Antifungal shampoos such as ketoconazole are used for this purpose and have shown a benefit in pattern hair loss.⁷ GHK-Cu, a copper peptide the body produces naturally, has been studied for its role in reducing inflammation and supporting tissue repair.⁸

4. Stress and the growth cycleTelogen effluvium

Cross-section of an empty follicle in its resting phase, with no hair shaft growing from it — A follicle pushed into its resting phase. Nothing is damaged; it has simply stopped producing for a while. Illustration, not a photograph.

Significant physical or emotional stress, illness, rapid weight loss, or a major life change can push many follicles out of the growth phase and into shedding at once. This is called telogen effluvium, and it usually shows up as diffuse thinning across the scalp two to three months after the trigger.

What helps

This type of shedding is often temporary and resolves once the underlying cause is addressed. Managing stress, improving sleep, and supporting overall health aid recovery. Importantly, no topical product substitutes for dealing with the trigger itself, which is why an honest routine treats this cause differently from the others.

5. Nutrition and ageDeficiencies and follicle aging

Three panels showing the same follicle across successive cycles, each time producing a shorter, finer hair — The same follicle across three cycles. The growth phase shortens, and each hair comes back a little finer than the last. Illustration, not a photograph.

Deficiencies in iron, protein, vitamin D, and other nutrients can impair hair growth, and the natural aging process gradually shortens the follicle's growth phase. Together, these lead to thinner hair and slower regrowth over time.

What helps

A balanced diet and correcting any deficiencies, ideally confirmed through testing with a doctor. Ingredients such as biotin support the structure of the hair strand, though they cannot overcome a hormonal or genetic cause on their own.

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Why most treatments only touch one cause

Two problems explain why so many men try product after product with little to show for it.

The first is that most treatments address a single cause. Minoxidil works on blood flow. Finasteride works on DHT. Neither touches inflammation, and both leave the others working against you. Fighting one front while four stay open is a slow way to lose ground.

Which of the five causes each one actually touches:

Cause	Minoxidil	Finasteride
1. Genetics and DHT	✗	✓
2. Scalp blood flow	✓	✗
3. Scalp inflammation	✗	✗
4. Stress and the growth cycle	✗	✗
5. Nutrition and age	✗	✗

Both are useful for the cause they address. Neither was built for the other four.

The second is absorption. The outer layer of the scalp, the stratum corneum, is a barrier that limits how much of an applied ingredient reaches the follicle below.⁹ A large share of most topicals stays on the surface and washes away before it is absorbed, so even the right ingredient may never reach the follicle in a meaningful amount.

Cross-section of the scalp. On the left a topical sits on the outer barrier layer; on the right microneedles open channels and the serum reaches the follicle — Left: a topical held on the surface by the outer layer of the scalp. Right: the same topical after 0.5mm channels are opened. Illustration, not a photograph.

One well-studied way to improve delivery is microneedling. Fine 0.5mm needles create temporary channels in the scalp that let topical ingredients penetrate more effectively, and the process itself appears to stimulate the follicle. In a controlled trial, men who combined microneedling with minoxidil grew significantly more hair than those using minoxidil alone.¹⁰

What an effective at-home approach has to do

Put the five causes together and a realistic at-home approach has to do three things at once.

1Reach the follicle. Get the active past the scalp barrier instead of leaving it on the surface.
2Target more than one cause. Address the modifiable causes together, not just DHT or just blood flow.
3Be simple enough to keep doing. A routine abandoned in a month changes nothing.

Most products manage one of these. Very few manage all three, which is the gap the following approach was built to close.

A 0.5mm gold-tipped micro-infusion device being tapped onto a man's hairline — The device is used on a clean, dry scalp, once a week, for about two minutes.

The Aurelian Protocol

The Aurelian Protocol is an at-home system designed around all three. A 0.5mm microneedling device opens the delivery channels, and a serum then carries actives that target the three modifiable causes at once: saw palmetto for DHT, rosemary and caffeine for circulation, and GHK-Cu for inflammation and repair. It is used once a week and takes about two minutes.

It will not change genetic or age-related factors, and it cannot restore a follicle that is no longer active. It targets the causes that can still be influenced, while the follicle is alive. Individual results vary.

It is backed by a 120-day return window, so you can judge it against your own hairline instead of a claim.

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Free 2-minute assessment · 120-day returns

When to see a doctor

Sudden hair loss, hair falling out in patches, or hair loss with other symptoms should be evaluated by a doctor or dermatologist, who can identify the specific cause and recommend treatment. If you take other medications, check with your provider before starting or combining treatments.

Frequently asked questions

How do I know which of the five is affecting me?

The pattern of your hair loss and your history give strong clues, which is what the short assessment is built to sort out. Sudden or patchy loss should be checked by a doctor, since it can point to a cause outside these five.

Can hair loss be reversed?

It depends on the cause and how early it is addressed. Shedding from stress or nutrition is often temporary. Androgenetic alopecia is progressive, but treatment started while the follicle is still active can slow it and, in some cases, improve density. A follicle that is no longer active cannot be restored without a transplant.

Does minoxidil work for everyone?

No. Studies suggest only about 3 to 4 in 10 men respond, partly because minoxidil must be activated by a scalp enzyme not everyone produces in sufficient amounts. It also addresses only blood flow, one of several causes.

Is at-home microneedling safe?

Devices with short 0.5mm needles are generally considered low-risk when used as directed on a clean scalp. Start with clean skin, follow the instructions, and consult a doctor if you have a scalp condition or take other medications.

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Sources

American Academy of Dermatology Association. "Do you have hair loss or hair shedding?" aad.org.
Ho CH, Sood T, Zito PM. "Androgenetic Alopecia." StatPearls. NCBI Bookshelf; updated 2024.
Mella JM, et al. "Efficacy and safety of finasteride therapy for androgenetic alopecia: a systematic review." Arch Dermatol. 2010;146(10):1141-1150.
Prager N, et al. "A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia." J Altern Complement Med. 2002;8(2):143-152.
Goren A, et al. "Novel enzymatic assay predicts minoxidil response in the treatment of androgenetic alopecia." Dermatol Ther. 2014;27(3):171-173.
Panahi Y, et al. "Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial." Skinmed. 2015;13(1):15-21. · Fischer TW, et al. "Effect of caffeine and testosterone on the proliferation of human hair follicles in vitro." Int J Dermatol. 2007;46(1):27-35.
Pierard-Franchimont C, et al. "Ketoconazole shampoo: effect of long-term use in androgenic alopecia." Dermatology. 1998;196(4):474-477.
Pickart L, Margolina A. "Regenerative and protective actions of the GHK-Cu peptide." Int J Mol Sci. 2018;19(7):1987.
Prausnitz MR, Langer R. "Transdermal drug delivery." Nat Biotechnol. 2008;26(11):1261-1268.
Dhurat R, et al. "A Randomized Evaluator-Blinded Study of Effect of Microneedling in Androgenetic Alopecia: A Pilot Study." Int J Trichology. 2013;5(1):6-11. (PMID 23960389)