To be clear, that doesn’t mean any evidence of hair loss is a sign of progressive hormonal changes. “Losing 50 to 100 strands a day is considered normal,” Dr. Engelman points out, “which resembles a pad of steel wool covering the drain or just a tangle of thread, depending on the density of your hair.” But if you find that you’re able to see increasingly more of your scalp, “there’s a good chance that’s due to hormones and aging,” she says.
2. It generally gets finer.
Just like with loss, thinning can happen as you head into your 40s because of the associated dip in estrogen. Relatively more testosterone floating around in your system can cause your hair follicles to shrink over time, Dr. Engelman says. Tinier follicles, in turn, sprout finer hairs. But the same genetic predisposition noted above is really what determines how much thinning you’ll see and how rapidly, Dr. Goh notes. So if you inherited androgen-sensitive hair follicles, you’re more likely to wind up with both female pattern hair loss and overall finer strands as you surpass 40.
3. It may become drier and more brittle in texture.
Natural hormonal factors aren’t the only thing that can prompt noticeable hair shifts at this stage of life; there are also “all the things we do to it,” like applying heat, using chemical products on it, and coloring it, Dr. Shepherd points out, which can change your strands’ overall feel and strength. TBH, harsh styling habits can make hair brittle, frayed, and more prone to breakage at any age, but over the course of years, the hair’s ability to withstand everything we put it through does take a hit, she says. The impact of other everyday factors like exposure to sunlight and environmental pollutants can also build with time, contributing to dryness, Kristin Lo Sicco, MD, a board-certified dermatologist at NYU Langone who specializes in scalp and hair disorders, tells SELF.
At the same time, your skin may produce or retain less natural oil as you age—due to the same estrogen dip noted above—which can lead to a Sahara-like scalp as well as parched strands, Dr. Goh points out. (It’s the same reason you might find yourself reaching for a thicker, more hydrating moisturizer as you hit your 40s and beyond.)
Folks with curly hair might be especially vulnerable to these texture changes, as well as the damage and loss that can follow, because this hair type tends to be more fragile, Dr. Goh notes. “You might not even be doing much chemical processing or intense styling, but with normal exposures and weathering, it can experience breakage at this age.”
4. It could lose some of its previous luster.
A shift in the appearance of your hair can go hand-in-hand with the texture changes mentioned above. Less overall moisture coating your skin and scalp also means less of it can travel down each hair shaft and give each piece its shine, Dr. Goh says. And years of exposure to heat, chemicals, and environmental muck can also strip away some of your hair’s natural gloss, leaving it looking duller, Dr. Lo Sicco notes. It could be the first difference you notice or one that comes alongside brittleness and breakage.
5. And yes, it could sport some (more) grays.
You know by now that gray strands can make themselves known before age 40, but after this point, you’re especially likely to notice them. We start to lose the pigment-producing cells in our hair follicles, called melanocytes, as we age, and the ones we have left stop making as much melanin (the tint that colors hair). The reason why isn’t clear, but we do know there’s a genetic component, Dr. Shepherd says. So there’s a good chance you’ll go gray around the same age and to a similar extent as your elders. And your ethnicity could influence when that happens for your family: Research suggests white people tend to see gray in their mid-30s, followed by Asian folks in their late-30s, and Black people in their mid-40s (though when it comes to other populations, data is lacking).
