Posted by Roots by GA Science Team
on July 31, 2026
Reviewed by the Roots by GA Science Team. This article is for education and is not medical advice. If you are worried about hair loss, speak with a doctor or dermatologist.
Hair thinning is rarely caused by just one thing. For most people it traces back to three underlying pathways working at the same time: DHT, a hormone that gradually shrinks hair follicles; inflammation at the scalp that disrupts the growth cycle; and nutrient gaps that starve follicles of what they need to build hair. Figuring out which of these is driving your shedding is the first real step toward doing something about it.
Here is how each pathway works, how to get a sense of which one is affecting you, and why the most effective approaches tend to address more than one at once.
First, what counts as normal shedding?
Losing some hair every day is completely normal - most people shed in the range of 50 to 100 hairs a day, according to the American Academy of Dermatology. Shedding becomes thinning when hairs are not fully replaced, or when they grow back progressively finer and shorter until the overall density drops.
Thinning tends to show up in one of two broad patterns, and the pattern is a clue to the cause. A patterned look - a receding hairline, a thinning crown, or a part that keeps getting wider - points toward hormone-driven miniaturization. A more diffuse thinning across the whole scalp, often starting fairly suddenly, points toward a trigger like stress, illness, or a nutrient gap. Many people have some of both.
Pathway 1 - How does DHT shrink hair follicles?
DHT (dihydrotestosterone) is a hormone your body makes from testosterone using an enzyme called 5-alpha-reductase. In follicles that are genetically sensitive to it, DHT binds to receptors and triggers a process called miniaturization: with each growth cycle the follicle gets a little smaller, the active growth phase gets shorter, and the hair it produces grows finer and less pigmented. Over years, some follicles stop producing visible hair altogether.
This is the mechanism behind androgenetic alopecia - pattern hair loss - which is the single most common cause of thinning. The American Academy of Dermatology estimates it affects roughly 50 million men and 30 million women in the United States. In men it usually shows up at the hairline and crown; in women it more often appears as diffuse thinning through the top of the scalp and a widening part, while the frontal hairline is preserved.
Because DHT is so central to pattern thinning, it is a common target in hair care. Botanicals such as saw palmetto have been studied for their role in this pathway, and prescription options like finasteride and dutasteride work here too - which is one reason it is worth understanding whether your thinning is hormone-driven.
Pathway 2 - How does scalp inflammation drive shedding?
The scalp is living tissue, and the environment around each follicle matters. Low-grade, ongoing inflammation and oxidative stress around the follicle - sometimes called microinflammation - can disrupt the normal hair-growth cycle and appear to accelerate miniaturization in people who are already prone to it.
Everyday contributors include oxidative stress, product buildup, sensitivity, and common scalp conditions like seborrheic dermatitis (the flaky, itchy kind of dandruff). A calm, healthy scalp environment gives the growth cycle its best chance, which is why antioxidant and soothing ingredients - for example ergothioneine and other follicle-protective actives - show up in scalp-focused formulas. If your scalp is persistently itchy, red, or flaky, that inflammation is worth addressing alongside anything else you do.
Pathway 3 - Which nutrient gaps cause thinning hair?
Growing hair is metabolically demanding, so your follicles are sensitive to shortfalls in the raw materials they depend on. Deficiencies most commonly linked to shedding include iron (measured as ferritin), vitamin D, zinc, and simply not getting enough protein. B-vitamins like biotin matter too - but supplementing biotin generally only helps if you are actually deficient, which is uncommon.
Nutrient-related shedding often takes the form of telogen effluvium: a temporary, diffuse shed that follows a trigger such as illness, high stress, rapid weight loss, or childbirth, typically showing up two to three months after the event. The important nuance is that supplements only move the needle if you have a gap to fill - so the smartest first step for diffuse shedding is usually to get key levels tested rather than guess.
How do you know which pathway is affecting you?
You cannot fully diagnose hair loss at home, but a few signals help you orient:
- A receding hairline, thinning crown, or widening part that develops slowly points toward the DHT / pattern pathway.
- Sudden, diffuse shedding a few months after a trigger (illness, stress, a big diet change, a baby) points toward telogen effluvium and possible nutrient gaps.
- A persistently itchy, flaky, or irritated scalp suggests inflammation is part of the picture.
In practice these overlap more often than not - which is exactly why single-cause thinking tends to disappoint. See a dermatologist promptly if the loss is sudden, patchy, comes with scalp pain or scarring, or is progressing quickly; those can signal causes that need specific medical treatment.
Why single-ingredient fixes often underperform
If thinning usually runs on three pathways at once, it follows that targeting only one can leave the others free to keep working against you. Someone who blocks DHT but ignores an underlying iron deficiency, or who fixes their nutrition but never calms an inflamed scalp, is only doing part of the job.
That is the thinking behind a multi-pathway routine - supporting DHT-related pathways, the scalp environment, and internal nutrition together rather than betting everything on one lever. Our Triple-Pathway Hair Supplement is formulated around exactly these three drivers, and the full Peptide Hair Growth System pairs it with a scalp-supporting shampoo and a peptide serum so all three are covered in one daily routine. If you want to go deeper on the ingredient side, we break down the peptide science behind these formulas. Whatever products you choose, the principle holds: address the whole picture, and give it time.
The bottom line
Hair thinning is usually a three-part story - DHT, inflammation, and nutrition - playing out together. Getting a sense of which pathways are most active for you, addressing them consistently, and looping in a professional when something looks unusual is the approach most likely to pay off. Hair grows slowly, so consistency over months, not days, is what makes the difference.
Frequently asked questions
What is the most common cause of hair thinning?
By a wide margin it is androgenetic alopecia - pattern hair loss driven by the hormone DHT acting on genetically sensitive follicles. It affects both men and women, though the pattern looks different between them.
Can hair thinning be reversed?
It depends on the cause and how early you act. Temporary shedding like telogen effluvium usually recovers once the trigger resolves. Pattern (DHT-driven) thinning is manageable but tends to need ongoing support rather than a one-time fix, and results are best when you start early. A dermatologist can tell you what is realistic for your situation.
Does DHT cause hair loss in women too?
Yes. Women can experience female-pattern hair loss, which typically shows up as diffuse thinning across the top of the scalp and a widening part. Hormonal shifts around pregnancy and menopause can add to it.
How long does it take to see improvement?
Hair grows slowly, so most approaches need about three to six months of consistent use before you can fairly judge them. Shedding often stabilizes before you see new density.
Should I get blood tests for hair loss?
For diffuse shedding it is often worth checking levels like ferritin (iron), vitamin D, zinc, and thyroid function, since correcting a genuine deficiency can help. Ask your healthcare provider which tests make sense for you.
Sources include the American Academy of Dermatology and peer-reviewed dermatology literature. Educational content only - not a substitute for personalized medical advice.
