Men’s Hair Thinning Isn’t Just Genetics—Here’s What Else Could Actually Be Driving It

Most men chalk hair thinning up to genetics and move on. But Dr. Rawn Bosley, a double-board-certified dermatologist and Nutrafol partner, has a different take: it’s almost never just one thing.

In a new episode of Radio Headspace, recorded as part of Nutrafol’s Stress Awareness Month collaboration with Headspace, Dr. Bosley breaks down real contributors to men’s hair thinning—from stress and cortisol to nutrition and cellular aging—and why the habits you’re building in your 30s and 40s matter more than you might think.

When Dr. Bosley first noticed changes in his own hair, he looked to his father’s genetics. But when he stepped back, he could see everything else that was going on at the same time: medical school, a poor diet, significant stress. “I wasn’t accounting for any of it,” he says.

In his practice, the conversation with male patients often starts from the same assumption—that thinning is inevitable. His job is to reframe that: there are factors you can’t control, and there are factors you absolutely can.

Outside of genetics, Dr. Bosley points to four main contributors:

Cortisol, one of the body’s main stress hormones, serves a purpose. The problem occurs when low-grade stress becomes constant, keeping cortisol elevated as a baseline rather than a response to a specific event. Dr. Bosley uses a clear analogy: a plane flying from New York to LA that drifts 1% off course over a long journey doesn’t end up in LA. Applied to the body, even stress you can’t feel may be affecting your hair.

Elevated cortisol can influence how testosterone is processed in the body and how sensitive hair follicles become to androgens. This means men can experience hormonal contributors to hair thinning even when their testosterone levels look normal on paper.

Men’s hormonal changes are slower and steadier than women’s. Rather than cyclical shifts, it’s a gradual decline in testosterone over time, accompanied by changes in how that testosterone is converted and how sensitive follicles become to its effects. Dr. Bosley makes a key point: normal hormone levels don’t necessarily mean hormones aren’t a factor. Hair follicles themselves can become more sensitive to androgens over time.

As the body ages, it loses some of its natural ability to course-correct nutritional gaps. Protein, vitamin D, zinc, and selenium are all important for normal cellular function. If you’re not consistently getting enough, the body starts to drift. “If you’re not giving yourself enough support,” Dr. Bosley says, “the aging process builds upon itself.”

Aging affects everything, including the hair follicle environment. The goal isn’t to stop the clock—it’s to give the body what it needs to stay on track as long as possible.

Unfortunately, by the time most men notice hair thinning, the underlying process has typically been going on for a while. It’s just crossed the threshold of visibility. “It takes quite a bit of advanced change for you to start noticing it,” Dr. Bosley says.

That’s why he advocates for a proactive approach, especially for men in their early 30s. Adding Nutrafol Men early—before thinning becomes significant—means addressing what may be affecting hair health rather than waiting until you’re chasing a problem. “Ten years later, you’ll thank me,” he tells his younger patients.

For men in their 50s and beyond who assume it’s too late: it isn’t. Nutrafol Men 50+ is formulated to address key root causes most relevant to aging men, including cellular aging and stress. Nutrafol Men 50+ is clinically tested to visibly improve hair growth.¹

Dr. Bosley is direct: no one has a perfect diet, and the idea that supplements are wasted effort isn’t accurate. The body requires specific minerals and vitamins to function normally. Supplementation fills the gaps that diet alone doesn’t consistently cover.

He describes it as the “Swiss cheese model”—using targeted support for the kinds of nutritional gaps that let hair health fall through. “Are you sure you’re getting enough vitamin D every day? Are you sure you’re eating enough foods that have zinc and selenium? If the answer is no, it’s kind of low-hanging fruit to supplement that.”

Dr. Bosley is candid about what he sees in his practice: by the time men come in about hair thinning, embarrassment is common. Many don’t say it out loud. His approach is to acknowledge it directly, then redirect to action.

His most practical recommendation: identify the one factor most likely driving your thinning—stress, nutrition, hormones, or aging—and start there. “Let’s pick one, work on that, and move on to the next one.” Hair health is a long biological journey, and consistency matters more than speed.

He likens it to a tree: you don’t want a tree to grow fast. It’ll be thin and easy to knock over. A strong, wide trunk takes time. Hair works the same way.

Dr. Rawn Bosley’s conversation with Radio Headspace goes deeper on all of this—including his own hair thinning experience, how to think about supplementation as you age, and why patience is one of the most important parts of any hair health plan.

Listen on Radio Headspace →

Is men’s hair thinning genetic?

Genetics can be a factor, but it’s rarely the only one. Stress, hormones, nutrition, aging, and daily habits can all contribute—and unlike genetics, many of these are within your control.

How does stress affect men’s hair?

Elevated cortisol can influence how testosterone is processed in the body and how sensitive hair follicles become to androgens. This can contribute to hair thinning even when hormone levels appear normal.

What nutritional gaps affect hair health in men?

Vitamin D, zinc, selenium, and protein are among the nutrients most relevant to hair health. Shortfalls are common and can accelerate the effects of cellular aging on hair follicles.

When should men start thinking about hair health?

The earlier, the better. By the time thinning is visible, the underlying process has often been underway for some time. A proactive, whole-body approach may be more effective than waiting until thinning becomes significant.

What’s the difference between Nutrafol Men and Nutrafol Men 50+?

Both are formulated to address key root causes of hair thinning in men, but Nutrafol Men 50+ is designed for root causes most relevant to aging men—including cellular aging and stress. Nutrafol Men 50+ is clinically tested to visibly improve hair growth.¹