Genetics and hair are closely related, with genes influencing hair color, type, and thickness. Maybe you inherited dad’s stubborn cowlick, mom’s raven black hair, or grandma’s fine texture. To a certain extent, our DNA writes the blueprint for our hair—determining other things too, like follicle shape (curly vs. straight), density, and even how early we might see those first few "wisdom highlights" (aka silver hairs).

But, is hair loss genetically inherited, too? Our genes also play a role in whether thinning and hair loss are in the cards. Even if you were dealt a (hair) losing hand, with proper management (through diet, sleep, stress reduction, and proper maintenance), you can come out (with more hair) on top!

Genes And Hair

Genetics may play a less-than-winning hand when it comes to hair loss, with alopecia being the primary cause of hair thinning and hair loss. Research suggests that hereditary hair loss accounts for the majority of cases, affecting an estimated 80 million people in the United States alone!

How Genetic Hair Loss Works

So, how does genetic hair loss work? In people with a genetic predisposition, hair follicles are sensitized to DHT (dihydrotestosterone), a byproduct of testosterone. This causes a process called miniaturization, where:

• The hair growth cycle shortens
• Hair follicles shrink in size
• Strands become thinner and shorter with each cycle until they eventually stop growing.

It is the hair follicles' genetic sensitivity to DHT that causes these effects.

When thinning hair arises from genetic, rather than environmental factors, it is referred to as androgenetic alopecia—the most common type. You’ll note this term, androgenetic alopecia, also known as male pattern baldness or female pattern hair loss, combines root words that together describe both the hormonal and hereditary nature of hair loss.

• “Andro-”, derived from the Greek word anēr (stem: andr-), means man or male
• “-Gen-” in genetics comes from the Greek genos
• “-etic” means pertaining to race, kind, or descent
• Genetic arises from the Greek genesis, meaning birth or origin

Don’t go blaming dad just yet—both women and men have androgens (male hormones) that are intertwined with the genes we inherit that lead to hair loss.

Your Hair Heritage: The Responsible Genes

“Do I inherit hair loss only from my mother’s side?” or, “Is it dad’s fault I’m losing my hair?”  It is a common myth that your mother’s genes or your father’s are the sole reason your hair is falling out. In fact, hair loss is polygenic, meaning it is passed down from both maternal and paternal sides and influenced by dozens of genes inherited from both parents.

So, what genetics determine hair loss? There are over 200 genes linked to androgenetic alopecia, but here are the primary culprits:

The AR gene: There is definitely a connection between the AR gene and hair loss, with the AR (androgen receptor) gene being on the X chromosome (inherited from the mother). This gene is a major determinant of the sensitivity of your hair follicles to DHT (the main hormone that causes thinning). When hair follicles become overly sensitive to androgens, it causes them to shrink.

Genes on Non-Sex Autosomes: Sorry, Dad, this doesn’t mean you’re off the hook! Genes from your father can influence the age of onset and the severity of the loss; however, there is no single "paternal gene" that is responsible. Scientists have identified a collection of over 60 genes linked to baldness, located on non-sex chromosomes (autosomes) that are inherited directly from your father.

Furthermore, studies indicate that approximately 80% of men with visible hair loss also had a balding father, an indisputable predictor.

The MTHFR Gene and Hair Loss: Although the MTHFR (Methylenetetrahydrofolate Reductase) gene is not a direct "baldness gene", mutations in this gene can impair the body's ability to convert vitamin B9 (folate) into its active form (methylfolate), which affects DNA synthesis, cell division, and processing of nutrients, leading to thinning and slower growth. This mutation often affects how our bodies use vitamin B12, which is vital for oxygen delivery to hair roots.

This gene also instructs our body to make an enzyme responsible for processing building blocks of proteins (amino acids), signaling genes to switch on and off, repairing DNA, and providing antioxidant protection, with its mutations potentially harming hair integrity.

Research has also found an association between MTHFR mutations and alopecia areata, an autoimmune condition where the body attacks its own hair follicles. The mutation can lead to higher levels of the amino acid homocysteine, which are linked to systemic inflammation and vascular issues that can affect the scalp and complicate androgenetic alopecia, potentially accelerating the thinning process by reducing blood flow to the follicles.

Don’t worry just yet! Up to 40% of the population with MTHFR variants never experience hair loss. It usually requires a combination of the mutation and inadequate folate intake to see symptoms.

Genetic Testing For Hair Loss: Is there a genetic test to predict if I will go bald? Some DNA tests (like 23andMe) can assess your risk based on genetic markers; however, these are not 100% definitive and cannot account for environmental factors like stress or diet.

The Hair You Define

But is hair loss always genetic? Not always. And even when it is, you can define your hair’s health, shine, and longevity through how you treat it. While you can’t change your DNA (though some trading parents was an option), you can adopt daily, healthy lifestyle choices to give yourself the best odds for defining the hair you deserve.

Think of your hair like a garden; you might start with a specific type of soil, but whether it flourishes depends entirely on the water, sun, and nutrients you provide. Genetics might provide the canvas, but YOU hold the brush! Not a painter type? Okay, enough with the metaphors. In other words, while genetics lay the foundation for hair loss, other factors can improve it (or hasten it!), altering its trajectory.

We know you don't want to leave your hair’s future to chance, so let’s look beyond your genes:

• Keep it clean: Regular shampooing with a clean shampoo that respects your scalp’s environment is essential for helping prevent scalp infections and a clogged, inflamed scalp. (While you’re at it, make sure to choose a moisturizing conditioner and scalp serum that promote optimal hair health.
• Get regular check-ups: Make annual visits to the doctor (nonnegotiable) to discuss concerns, get bloodwork to test for deficiencies, and check hormone levels. It's also important to identify any medical conditions (autoimmune or thyroid disorders) that could trigger hair loss.
• Manage stress: Feeling frazzled and have the hair fall to show for it? Stress acts like an accelerant to those genetically prone to male or female pattern baldness. Significant physical or emotional stress can potentially trigger sudden, widespread hair shedding (telogen effluvium) or patchy, autoimmune-related hair loss (alopecia areata). Dedicate yourself to understanding the link between hair loss and stress and the steps you can take against it. 
• Eat for your hair: Prioritize a balanced diet with ample iron, protein, and vitamins (like biotin and zinc) as deficiencies weaken hair. Read about the top nutrients to make staples in your diet for healthier hair here.
• Ditch the habit: Do whatever you can to stop smoking, which may damage the blood supply to follicles—one more reason for you to put the butt out.
• Move more: Take up exercise and healthy play to get your blood flowing for better oxygenation and nutrition for your scalp and body.
• Practice sleep hygiene: Beauty sleep is a thing. Make a point to get your zzz’s, as a rest deficit can disrupt the body's natural restorative processes, negatively affecting hair follicles and leading to thinning.

Disclaimer: This article and product references are intended for informational use only and are not intended to diagnose or treat any medical conditions.