Chronic Stress, Poor Recovery, and the Hair Cycle

You’ve probably heard that stress causes hair loss. It’s true, but the phrase gets thrown around so casually it’s nearly lost its meaning — we’re not talking about one stressful Tuesday leading to bald spots on Wednesday.

Hair follicles respond to significant physiologic stressors, and one classic result is telogen effluvium, which shows up with a delay because the follicles don’t immediately release the hair when the trigger occurs — shedding typically begins 2 to 4 months after the inciting event (Mirmirani & Fu, JAMA, 2021; Dakkak et al., American Family Physician, 2024). That means chronic stress can be relevant, particularly alongside poor sleep, under-eating, rapid weight loss, intense exercise without adequate recovery, illness, emotional trauma, or major life changes — stress can also indirectly affect hair by changing your eating habits, sleep, menstrual cycle, and overall physiologic state.

This is why I’m cautious about telling someone “it’s just stress” — that phrase can feel dismissive, and stress may well be contributing, but it’s still worth asking what’s happening underneath it: whether you’re eating enough protein, whether you’ve lost weight, whether your periods have gotten heavier or less predictable, and whether the shedding started a few months after a major life event. Those questions tend to be far more useful than the label “stress” on its own.

Medications Can Sometimes Be the Missing Piece

Medication-induced hair loss is easy to overlook because the medication is usually treating an entirely different problem. Many medications have been associated with hair shedding, and drug-induced alopecia commonly occurs through telogen effluvium — with timing that can be delayed by 2 to 4 months, making the connection even harder to recognize (Tosi et al., Drug Safety, 1994; Mirmirani & Fu, JAMA, 2021).

Medications reported to contribute to hair shedding include beta blockers, some antidepressants, lithium (the most common medication cause) and other mood stabilizers such as valproate, anticoagulants such as warfarin, retinoids, and isoniazid (Mirmirani & Fu, JAMA, 2021; Dakkak et al., American Family Physician, 2024). Beta blockers are a good example — propranolol and metoprolol in particular have been associated with telogen effluvium, and alopecia is listed as an adverse reaction on the propranolol label (Dakkak et al., American Family Physician, 2024; U.S. Food and Drug Administration, n.d.) — and retinoids are another, capable of causing generalized shedding and thinning in some people (Tosi et al., Drug Safety, 1994).

None of that means you should stop a medication because you suspect it’s behind your hair loss — never stop a prescribed medication without talking to the clinician who prescribed it. Drug-induced hair loss is usually reversible after the treatment is stopped (Tosi et al., Drug Safety, 1994). What’s worth looking at instead is the timeline: whether the medication started shortly before your hair changed, whether the dose was increased, or whether the shedding began a few months after either change. The medication isn’t always the whole story, but it can be an important piece of it.

Nutrition, Weight Loss, Hair Practices, and Scalp Health

This last category is intentionally broad, because several seemingly unrelated problems can affect the hair in similar ways.

Nutritional gaps. Hair production requires adequate energy and nutrients, and malnutrition and rapid weight loss are recognized triggers of telogen effluvium (Mirmirani & Fu, JAMA, 2021). Inadequate protein, iron, zinc, or other nutrient intake can contribute to noticeable hair loss — particularly with restrictive diets, eating disorders, major dietary changes, malabsorption, or inadequate calorie intake.

More supplements aren’t automatically better. The hair supplement industry has created the impression that if a little biotin, zinc, selenium, or vitamin A helps, more must help more. It doesn’t.

• Excessive zinc supplementation can interfere with copper absorption and induce copper deficiency, with attendant anemia and neutropenia — evidence of induced copper deficiency has been reported at intakes of 100–300 mg/day, and the adult tolerable upper intake level is 40 mg/day outside of specific medical supervision (Fosmire, American Journal of Clinical Nutrition, 1990; Sandstead, American Journal of Clinical Nutrition, 1995). 
• Excessive selenium intake, above the adult upper limit of 400 µg/day, is itself associated with hair loss among other effects; alopecia is a hallmark of selenosis, and in the SELECT trial, 200 µg/day of selenium significantly increased the risk of alopecia (van Zuuren et al., Cochrane Database of Systematic Reviews, 2013; Winther et al., Nature Reviews Endocrinology, 2020). 
• Retinoids (vitamin A), in turn, can cause hair loss as well (Tosi et al., Drug Safety, 1994). If you’re taking a multivitamin, a “hair vitamin,” a prenatal, a collagen product with added nutrients, and several individual supplements at once, it’s worth adding up the total dose rather than assuming each product is simply helping on its own.
  

Rapid or crash weight loss. Significant calorie restriction and rapid weight loss are classic setups for increased shedding (Mirmirani & Fu, JAMA, 2021). Your body has limited resources, and hair production matters for appearance but isn’t a survival priority — so when you’re losing weight quickly, eating substantially less, or not getting enough protein and micronutrients, the hair cycle responds. That’s one reason someone can finish a successful weight-loss phase and then wonder, a few months later, why their hair is suddenly shedding. The delay can make the connection easy to miss.

Tight hairstyles and traction alopecia. Your hairstyle can matter more than you’d think. Repeated tension from tight ponytails, buns, braids, cornrows, extensions, or weaves can cause traction alopecia — early on, easing up on the tension may allow recovery, but prolonged and repeated tension can eventually damage the follicle permanently and result in scarring (Afifi et al., Pediatric Dermatology, 2021; Imhof et al., American Academy of Pediatrics, 2020). A simple rule of thumb: if your hairstyle hurts, it’s too tight. Pain, stinging, crusting, broken hairs around the hairline, or progressive recession are all worth paying attention to.

Scalp conditions. Finally, don’t overlook the scalp itself. Psoriasis, fungal infections, inflammatory scalp disorders, and alopecia areata can all cause hair loss without looking anything like classic female pattern thinning. Scalp psoriasis, for example, can cause hair loss — most commonly in lesional skin, sometimes as a generalized telogen effluvium, with regrowth in most cases but rarely scarring (George et al., Clinical and Experimental Dermatology, 2015). Alopecia areata tends to look different altogether — sudden, smooth, round or oval patches, sometimes with itching, tingling, or burning. Hair loss accompanied by pain, burning, significant itching, redness, scaling, sores, pustules, or shiny patches where follicles seem to have disappeared calls for an actual scalp exam, not a handful of supplements.

Why These Overlooked Causes of Hair Loss in Women Get Missed

Normal bloodwork is reassuring, but it doesn’t mean nothing is happening. Hair loss gets diagnosed primarily by looking at the pattern, timeline, scalp, medications, medical history, family history, and — when it’s appropriate — laboratory testing; for diffuse shedding, the standard targeted labs are TSH, ferritin, and 25-hydroxyvitamin D (Mirmirani & Fu, JAMA, 2021). There’s no single blood test that can hand you the answer “this is why you’re losing your hair,” and ordering every possible lab isn’t automatically better medicine. 

The evaluation should follow the clues instead: a woman with heavy periods and diffuse shedding needs a different workup than a woman with a widening part and a strong family history of female pattern hair loss; a woman with irregular periods and new facial hair needs a different conversation than someone whose shedding began three months after major surgery; and a woman with scalp burning and patchy loss needs a different approach entirely. The pattern comes first, and the testing exists to answer the questions that pattern raises — not the other way around.

The Bottom Line

There are plenty of reasons your hair can change that have nothing to do with simply getting older. Perimenopause, depleted iron stores, thyroid dysfunction, PCOS, hormonal contraception, significant stress, medications, nutritional problems, rapid weight loss, traction, and scalp conditions can all enter the picture depending on what your hair is actually doing — and often it’s not just one of them. 

You can have genetic follicle miniaturization plus telogen effluvium after a major stressor. You can have perimenopausal hormonal changes plus an underlying nutritional problem. You can have a perfectly normal ferritin and still have female pattern hair loss. That combination of possibilities is exactly why the overlooked causes of hair loss in women rarely fit into one lab panel or one diagnosis — and why I don’t believe in a one-size-fits-all hair-loss workup.

If you’ve been told your labs are normal but your hair is clearly changing, that’s not a reason to panic or to start taking every hair supplement you can find — it’s a reason to look at the whole picture. And if you’ve worked through the common causes, the overlooked causes here, and the obvious explanations, and your hair is still thinning, the investigation is about to get more interesting: in the next post, we’ll go beyond the standard hair-loss workup and look at some of the deeper factors worth considering when the usual answers don’t quite explain what’s happening.