If hair thinning runs in your family, you may wonder whether the same thing will happen to you. Genetics can strongly influence the risk of some types of hair loss, but they do not determine exactly if, when, or how much hair you will lose.
The strongest genetic link is seen with pattern hair loss. Rather than being caused by a single “baldness gene,” this common condition is polygenic, meaning many genetic variants contribute to risk.
What Type of Hair Loss Is Most Closely Linked to Genetics?
Androgenetic alopecia, commonly called pattern hair loss, is the form most strongly associated with inherited risk.[1]
In men, it often begins with recession at the temples, thinning at the crown, or both. In women, pattern hair loss more often appears as a widening part or a gradual reduction in hair density across the top of the scalp.
In genetically susceptible follicles, androgen signaling can contribute to miniaturization. Over time, affected follicles produce hairs that are finer, shorter, and less visible.[2] The genetics of female pattern hair loss are less clearly understood than those of male pattern hair loss, and the genetic factors involved may not be identical.
Does Hair Loss Come From Your Mother’s Side?
The idea that baldness is inherited only from your mother’s side is a myth.[3]
One important gene associated with male pattern hair loss is the androgen receptor, or AR, gene, which is located on the X chromosome. Because men inherit their X chromosome from their mother, this helped create the belief that the maternal side determines baldness.
But pattern hair loss involves many genes across different chromosomes. Those genetic variants can be inherited from either parent. A history of pattern hair loss on your mother’s side, father’s side, or both can therefore be relevant.
Family history can provide useful clues, but one relative cannot reliably predict what will happen to your hair.
How Much Does Genetics Affect Hair Loss?
Genetics plays a substantial role in pattern hair loss. Twin and family studies have found high heritability, particularly for male pattern hair loss.[4]
Heritability, however, is often misunderstood. An estimate of around 80% does not mean that 80% of one person’s hair loss is caused by genes. It describes how much of the variation in a trait within a studied population is associated with genetic differences.
Genetic risk also cannot tell you the exact age at which hair loss will begin, how quickly it will progress, or how severe it will become.
What Have Genetic Studies Found?
Large genome-wide association studies have identified many genetic regions associated with pattern hair loss. These findings reinforce that there is no single gene responsible for the condition.
Research has linked genetic risk to several biological processes, including androgen signaling and pathways involved in hair-follicle development, regeneration, and growth.
Genetic research has been stronger in men and in populations of European ancestry. Research in women and more diverse populations is still developing, so current risk estimates may not apply equally well to everyone.
Can Genetic Testing Predict Hair Loss?
At-home genetic tests may estimate whether you carry certain variants associated with pattern hair loss, but they cannot tell you with certainty whether you will develop it.
Because many genes are involved, genetic testing gives only part of the picture and cannot reliably predict the exact age of onset, pattern, or severity of future hair loss.
Routine genetic testing is therefore not usually needed to diagnose pattern hair loss. Dermatologists generally rely on the pattern of thinning, medical history, family history, and scalp examination.
Can Genetics Predict the Best Treatment?
Not yet in routine care.
Researchers are studying whether genetic differences influence how people respond to hair-loss treatments, but there are currently no genetic markers sufficiently validated to routinely choose a treatment based on a person’s DNA.
Treatment decisions are instead based on the type of hair loss, medical history, and individual health considerations.
When Should Hair Loss Be Checked?
Family history can make pattern hair loss more likely, but not every type of hair loss is genetic. Nutritional deficiencies, thyroid disorders, autoimmune conditions, medications, illness, stress-related shedding, scalp disease, and repeated tension on the hair can also contribute.
Consider seeing a healthcare professional if you notice sudden or excessive shedding, distinct bald patches, scalp pain or inflammation, rapidly changing hair loss, or thinning that concerns you. Identifying the type of hair loss matters because different causes require different approaches.
The Bottom Line
Genetics can strongly influence the likelihood of developing pattern hair loss, but your DNA is not a precise forecast. Pattern hair loss is influenced by many genes rather than one inherited “baldness gene,” and risk can come from both sides of the family.
Family history is useful information, but the pattern of your hair loss and a clinical evaluation are more useful than genetic testing for determining what is actually happening.
Reference
[1] https://ijdvl.com/genetic-and-molecular-aspects-of-androgenetic-alopecia/
[2] https://www.sciencedirect.com/science/article/abs/pii/S0190962201432804
[3] https://www.health.harvard.edu/a_to_z/hereditary-patterned-baldness-a-to-z