‘One-way street’: The difference between hair shedding and thinning - and when to seek treatment

One day, not so long ago, I felt a suspiciously cool breeze caress my scalp. Instantly, alarm bells rang.

As someone who grew up with a veritable nest of very bushy hair, the feeling was completely foreign. Where previously it had shielded me from the elements, I now found myself cruelly exposed. And for four in 10 women who will experience some degree of hair thinning, it’s difficult to know the best path forward.

Whether the level of shedding I was experiencing was temporary, or cause for greater concern, I wasn’t totally sure.

And so, seeking an explanation for the suspicious change in my hair’s density, I took the only advisable route: I consulted an expert.

What is the difference between hair thinning, shedding and balding?

Speaking to nine.com.au, Professor Rod Sinclair of Sinclair Dermatology said these terms can be narrowed down into two distinct categories – and that generally, only one is cause for concern.

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Hair operates in a continuous, repeating cycle of four phases: Anagen (growth), Catagen (transition), Telogen (resting), and Exogen (shedding).

At any given time, about 85 per cent to 90 per cent of your hair is actively growing, while individual follicles cycle independently to prevent all hair from falling out at once.

Sinclair clarified the shedding phase is a natural part of the growth cycle – with new hair from a follicle pushing out older strands. On average, 100 out of around 100,000 hairs are shed per day.

While the volume of shedding can be exacerbated by a number of causes, it’s often temporary and reversible.

Meanwhile, hair thinning, according to Sinclair, was “generally another term for balding,” and is far more difficult to treat.

“If you can see scalp through it, but it’s not totally bald – so it doesn’t look like your forehead – then you call that thinning,” he said.

What are some common causes of balding or excessive shedding?

Unlike men, who typically experience receding hairlines, women generally experience thinning in a very different way.

According to dermatologist Dr. Firdous Ibrahim, women are effected by “diffuse thinning” all over the scalp, the most common causes of which include:

Telogen effluvium

This term is used to describe shedding caused by a “a major physical or emotional stressor,” Ibrahim told nine.com.au.

It is one of the most common causes of hair loss in women, however, per an online resource published by Melbourne Skin and Dermatology, it often resolves on its own once the root cause is addressed.

“We see this frequently after childbirth, major surgeries and severe illnesses like a severe fever or infection,” Ibrahim said.

On that note, Sinclair added it can also be secondary to rapid weight loss, which can push the hair’s growth cycle into the shedding phase prematurely.

“Lots of people on Manjaro and Ozempic, if they’re losing more than about four or five kilograms a month, they’ll get hair shedding,” he said.

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This form of shedding is considered “non-scarring,” meaning there’s no damage to existing hair follicles.

Androgenetic alopecia

Also known as Female Pattern Hair Loss, this is a genetic and hormonal condition.

While women have lower levels of androgens (male hormones) than men, some women’s hair follicles are highly sensitive to them.

According to Ibrahim, this causes the follicles to “shrink over time and produce thinner, weaker hairs.”

Hormonal imbalances

Conditions like Polycystic Ovary Syndrome (PCOS) can cause an overproduction of androgens, leading to thinning hair on the scalp.

Nutritional deficiencies:

Women are susceptible to hair loss caused by low iron levels, with around one in three affected in some form on a global scale. Deficiencies in Vitamin D, B12, and overall protein intake also heavily impact hair follicle health.

What are the early signs of balding?

If you’re currently concerned about potential balding, Sinclair cited a number of early warning signs to keep tabs on.

One sign that may raise alarm bells is a notable decrease in the thickness of your ponytail. If you notice you’re having to tie your hair tie tighter than usual when putting up your hair, this could be cause for concern.

According to him, it’s normal on the scalp to have three or four hairs coming out of each pore: “What happens in baldness is that the follicles, instead of producing three or four hairs, start to only produce one hair.”

The appearance of short, wispy hair may also be a sign your hair is thinning, indicating that hair follicles have begun to shrink “so you notice that the hair weight becomes different.”

He then cited what’s known as the ‘Sinclair Scale,’ and a widening of the central part-line as another red flag.

“Once you actually start to see scalp, then you know you’ve got the balding processes started. Once it starts, it’s a one-way street, it just gets worse and worse.”

Can shedding present similarly to balding, then grow back?

Short answer: yes.

Significant shedding can reduce the overall density enough for your scalp to become more visible – so it can often look very similar to progressive thinning.

But with telogen effluvium, the follicles typically remain healthy.

Once the cause has resolved, the shedding normally slows to allow for new growth – but recovery is gradual, and can take months as the cycle resets.

It is also possible to have both telogen effluvium and female-pattern hair loss at the same time – in which case, the shedding may improve, but some underlying thinning might remain.

When is it wise to consult a doctor?

Speaking to nine.com.au, GP Dr Mark Fazlian advised paying your doctor a visit if the hair loss is “sudden, persistent, getting worse or causing visible thinning.”

Key symptoms worth getting checked include:

• Smooth bald patches.
• Loss of eyebrows or eyelashes.
• Scalp pain, burning, redness, scaling, crusting or pustules.
• Smooth or shiny areas where the follicle openings appear to have disappeared.
• Rapidly receding hairline.
• Irregular periods, increased facial hair or severe acne.
• Heavy periods, fatigue, weight changes or symptoms of thyroid disease.
• Hair loss after starting a new medication.

“Pain, inflammation or shiny areas of scalp are particularly important because they may indicate scarring hair loss, which can become permanent if treatment is delayed,” Fazlian said.

Next steps

When asked about the best approach to addressing excessive hair shedding or hair thinning, Dr. Ibrahim emphasised that the most important step is getting a proper diagnosis first.

She noted that the effectiveness of treatment is often directly relative to how quickly the root cause is addressed – but that jumping the gun without identifying that prior to treatment would likely yield no real results.

Once diagnosed, treatments vary by cause.

Topical minoxidil:

Known across dermatology as the ‘gold standard’ (and only FDA-approved) topical treatment for female pattern hair loss, it aims to prolong the ‘growth phase’ of your hair follicles.

Targeted supplements:

If blood tests bring to light any deficiencies, prescription iron, Vitamin D, or specific amino acid supplements can work to reverse shedding – but Ibrahim warns against use of one common over-the-counter product.

“I always advise patients to avoid generic ‘hair gummies’ and test their actual blood levels first,” She noted.

Underlying hormones:

For patients with PCOS or related hormonal imbalances, anti-androgen medications (like Spironolactone) can be highly effective in stopping hair loss.

Whatever the cause, the path forward can yield positive results and help you reclaim your hair – provided you consult a GP or dermatologist along the way.