Androgen Receptor Polymorphisms and Hair: What Your Genes Say
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Androgen receptor polymorphisms are small, common differences in the gene that builds the androgen receptor, and they are the best-established genetic link to pattern hair loss. This guide explains what those differences are, why they sit on the X chromosome, what they can and cannot tell you about your own hairline, and what is genuinely worth doing if thinning runs in your family.
The androgen receptor is the protein that lets hair follicles respond to androgens such as DHT. Its gene, AR, sits on the X chromosome and varies from person to person. MedlinePlus Genetics says the AR gene is the only gene confirmed to be involved in androgenetic alopecia, and that variants may make receptors easier to stimulate. Genes load the dice, but DermNet says genetic tests cannot yet predict balding reliably.
Key takeaways
- The AR gene makes the androgen receptor, the switch that lets follicles respond to DHT and other androgens.
- Variation in the AR gene is the only genetic link to pattern hair loss that studies have confirmed, according to MedlinePlus Genetics.
- The AR gene is on the X chromosome, which men inherit from their mother. But DermNet says several genes are involved and they come from both parents.
- DermNet says genetic testing to predict balding is currently unreliable.
- Genes explain hair loss, not hair shedding or hair breakage, which have their own causes.
What are androgen receptor polymorphisms?
A polymorphism is a common variation in a gene, a difference that many healthy people carry, rather than a rare mutation that causes disease. The androgen receptor gene, called AR, has a well-known variable stretch: MedlinePlus Genetics explains that a short DNA segment, CAG, is repeated several times in one region of the gene, and that in most people the number of repeats ranges from fewer than 10 to about 36. That repeat length, along with other small differences in the gene, is what researchers usually mean when they talk about variation in the androgen receptor.
The receptor itself matters because androgens cannot act on a cell without it. Testosterone and its more potent relative DHT circulate in everyone, men and women alike. Whether a hair follicle responds to them depends on whether it carries androgen receptors and how readily those receptors switch on. Small differences in the gene can nudge that sensitivity up or down, which is why two people with similar hormone levels can have very different hairlines. Our guide to scalp androgen receptors explains why receptors in some scalp areas behave differently from others.
How are androgen receptor polymorphisms linked to pattern hair loss?
Androgen receptor polymorphisms are linked to pattern hair loss because variation in the AR gene is the one genetic factor that studies have confirmed in androgenetic alopecia, according to MedlinePlus Genetics. Researchers suspect several genes play a role, but the AR gene is the only one with confirmed involvement. The suggested mechanism is that some variants produce receptors that are more easily stimulated by androgens, which increases receptor activity in hair follicles.
MedlinePlus is careful to add that it remains unclear exactly how these changes raise the risk, and that the variants appear most often in men whose hair loss starts early. That honesty is useful. The genetic link is real, but it is a risk factor rather than a verdict, and it does not explain every case. DermNet describes male pattern hair loss as a combination of androgens and genetic predisposition, with DHT shortening the growth phase of the hair cycle from its usual three to six years to just weeks or months in susceptible areas. The result is miniaturisation: each new hair in the affected zone grows finer and shorter than the last.
| Factor | What the evidence says | Source |
|---|---|---|
| AR gene variation | The only gene confirmed to be involved in androgenetic alopecia | MedlinePlus Genetics |
| Other genes | Several are suspected; together they shape age of onset, pattern and severity | MedlinePlus Genetics, DermNet |
| Androgens (DHT) | Needed for pattern loss in men; shorten the growth phase in susceptible follicles | DermNet |
| Age | Up to half of white men show some loss by 50, possibly 80% by 70 | DermNet |
| Genetic testing | Currently unreliable for predicting balding | DermNet |
Does baldness really come from your mother's side?
Baldness comes from both sides of the family, although the popular idea about the mother's side contains a grain of truth. The AR gene sits on the X chromosome, as MedlinePlus Genetics confirms, and men inherit their single X chromosome from their mother. So the one confirmed gene does travel down the maternal line in men. That is where the old advice to look at your mother's father comes from.
The rest of the story undercuts it. DermNet states that several genes are involved in male pattern hair loss and that the susceptibility genes are inherited from both mother and father, which is why it can be inherited from either side of the family. MedlinePlus Genetics adds that the overall inheritance pattern is unclear because many genetic and environmental factors are involved, although the condition does cluster in families and having a close relative with patterned hair loss is a risk factor. In practice, look at both sides: a bald father, a bald maternal grandfather and thinning aunts all count.
Can a genetic test predict your hair loss?
A genetic test cannot reliably predict hair loss at present, because DermNet states that genetic testing for the prediction of balding is unreliable, and says the same for female pattern hair loss, where testing is not recommended. That matters because direct-to-consumer tests are sold with confident-sounding reports. A result that shows a common AR variant tells you something you could usually have guessed from your family, and it cannot tell you when, how fast or how far thinning will go.
Your own scalp is a far better guide than a DNA kit. Dated photos of your hairline, crown and parting, taken every few months in the same light, will show change long before a test could. If you want to understand what laboratory testing of the receptor can and cannot show, our page on androgen receptor testing goes through it without the sales pitch.
Save your money
Before paying for a hair-loss DNA test, write down which relatives on both sides have thinning hair and at what age it started. That free family history carries most of the same information, and DermNet says the tests are unreliable anyway.
Do androgen receptor polymorphisms matter for women?
They may matter for women too, but the picture is less clear than it is for men. DermNet describes female pattern hair loss as having a strong genetic predisposition with a polygenic mode of inheritance, meaning many genes contribute and they can come from either parent or both. MedlinePlus Genetics notes that androgens play a role in female pattern hair loss, but that other, as yet unknown factors are also involved.
That uncertainty is why DermNet prefers the term "female pattern hair loss" to "female androgenetic alopecia": the link to androgens is not settled. Many women with thinning have normal hormone tests. The pattern is also different, usually a widening parting and thinning over the top rather than a receding hairline, and it rarely leads to total baldness. DermNet notes it is more common after the menopause, with around 40% of women showing some signs by age 50. Our guide to female pattern hair loss covers the signs and stages.
Is it hair loss, hair shedding or hair breakage?
Androgen receptor polymorphisms only help explain one of three different problems, and it is worth being clear which one. Hair loss in the pattern sense is follicles producing progressively finer hairs over years, in a recognisable shape. That is the problem genes shape. Hair shedding is whole hairs falling early because the growth cycle was disturbed by a trigger such as illness, stress, crash dieting or low iron; DermNet says it usually shows two to four months after the trigger and settles. Hair breakage is the fibre snapping from heat, colour or rough handling, and has nothing to do with genes at all.
The distinction matters because the right response is different for each. Shedding usually needs time and a look at its trigger. Breakage needs gentler handling. Pattern thinning is gradual and worth a GP conversation early if it bothers you. The NHS reminds us that losing 50 to 100 hairs a day is normal, so a single heavy wash day proves nothing on its own. If you are unsure what is starting yours, our breakdown of what triggers and speeds androgenic alopecia helps sort the factors.
| Problem | Where genes fit | Typical sign |
|---|---|---|
| Pattern hair loss | Central. AR variation is the confirmed genetic link. | Receding temples, thinning crown or a widening parting over years |
| Hair shedding | Minor. Triggered by events, not inherited | Hairs with a white bulb at the root, all over, for a few months |
| Hair breakage | None. Caused by damage to the fibre | Short snapped pieces with no bulb |
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What can you actually do if pattern hair loss runs in your family?
If pattern hair loss runs in your family, the most useful things you can do are to watch early, act early and look after the hair you have. Genes cannot be changed, and no shampoo alters how your androgen receptors behave. What you can influence is how soon you notice change, how quickly you get proper advice, and how full and healthy your hair looks in the meantime.
Start with photos every three months. See your GP early if you notice change, since the NHS advises seeing a GP about hair loss before going to a commercial hair clinic, and a GP can rule out other causes such as thyroid problems or low iron. Day to day, a gentle routine matters more than people expect: thinning hair is finer, so it breaks more easily, and less breakage means more visible fullness. Cut down on heat, condition every wash, avoid tight styles, and use products that support a healthy scalp environment.
Grow Me® Hair Growth Shampoo £14.95
A daily-use shampoo with plant-based ingredients chosen to support a healthy scalp environment, so finer hair looks fuller and feels thicker after washing.
Grow More® Leave-In Scalp Elixir £25.50
A leave-in scalp elixir massaged into the parting or crown, for a scalp-care step that helps thinner areas look and feel healthier.
Condition Me® Hair Growth Conditioner £13.95
A conditioner that reduces tangling and breakage on finer hair, so more of the length you grow stays on your head.
When should you see a GP about inherited thinning?
You should see a GP about inherited thinning whenever it worries you, and sooner if the pattern looks unusual. The NHS suggests seeing a GP about hair loss before paying for a commercial hair clinic, and says hair loss that is sudden, patchy, itchy or painful needs checking. A GP can often tell the likely cause by looking at your hair and can arrange tests if something else might be involved.
A GP visit is also the right place for any conversation about medicines for pattern hair loss, which are outside what a hair-care brand can advise on. If your question is about products or a routine rather than a medical one, you can talk to Gail Waterman, our co-founder, as an AI avatar on the Watermans homepage. And if the loss is causing real distress, the NHS notes that a GP may be able to help you access counselling. Variants in the oestrogen receptor genes have been studied too, and our estrogen receptor polymorphisms guide explains why the results disagree.
What are the frequently asked questions about androgen receptor polymorphisms?
What are androgen receptor polymorphisms in simple terms?
They are common variations in the AR gene, which builds the androgen receptor. The best known is the number of CAG repeats in one part of the gene, which MedlinePlus Genetics says usually ranges from fewer than 10 to about 36.
Do androgen receptor polymorphisms cause baldness?
They raise the risk rather than cause it outright. MedlinePlus Genetics says AR variation is the only gene confirmed in androgenetic alopecia, but other genes and factors are involved and exactly how the variants act is still unclear.
Is baldness inherited from your mother?
Partly. The AR gene is on the X chromosome, which men get from their mother. But DermNet says several genes are involved and they come from both parents, so look at both sides of the family.
Can a DNA test tell me if I will go bald?
Not reliably. DermNet states that genetic testing for predicting balding is currently unreliable. Family history and photos of your own hair are more useful.
Do women carry the same genetic risk?
Women can inherit a predisposition too, but female pattern hair loss is polygenic and its link to androgens is less certain. Many women with thinning have normal hormone results.
Can a shampoo change my genes or receptors?
No. No shampoo changes your genes or how your androgen receptors work. Good hair care can reduce breakage and help thinning hair look fuller, which is its real value.
At what age does genetic hair loss start?
It can start in the teens, and MedlinePlus Genetics says the risk rises with age. DermNet reports up to half of white men have some loss by 50.
Is hair shedding a sign of genetic hair loss?
Not usually. Shedding is whole hairs falling after a trigger and tends to settle within months. Genetic pattern loss is gradual thinning in a pattern over years.
What is the bottom line on androgen receptor polymorphisms?
The bottom line on androgen receptor polymorphisms is that they are the clearest genetic clue we have to pattern hair loss, and still only a clue. The AR gene sits on the X chromosome, but other genes from both parents matter too, and DermNet says genetic tests cannot yet predict balding reliably. Your family history and your own dated photos tell you more than a kit.
If thinning runs in your family, watch early, see a GP if it worries you, and look after the hair you have. A gentle hair growth shampoo used as part of a low-damage routine is a practical first step towards fuller-looking hair.
Sources & references
- MedlinePlus Genetics, Androgenetic alopecia, checked 18 September 2026.
- MedlinePlus Genetics, AR gene, checked 18 September 2026.
- DermNet, Male pattern hair loss, checked 18 September 2026.
- DermNet, Female pattern hair loss, checked 18 September 2026.
- DermNet, Telogen effluvium (hair shedding), checked 18 September 2026.
- NHS, Hair loss, checked 18 September 2026.
Watermans products are 100% cosmetic and do not treat medical hair loss. Individual results may vary.
