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Expert Knowledge on SMP & Hair Restoration.

Everything you need to know about scalp micro pigmentation, hair loss, scar camouflage, and aftercare, written by practitioners, not marketers.

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Hair loss · Before the bloods

5 blood tests worth considering when your hair is thinning.

Before density SMP or a transplant, we want to know why the hair is going. Look past the shampoo aisle: read the pattern first, then test what the history points to.

Before the bloods

Dermatoscope examining diffuse thinning on a man’s crown — reading the hair loss pattern before blood tests

First: what kind of hair loss is this?

Diffuse shedding, patterned thinning and patchy loss have different causes. Blood tests help most in diffuse shedding; patterned thinning is usually diagnosed by examination alone.

Diffuse shedding

More hair in the shower, all over.

Think telogen effluvium and systemic triggers.

Patterned thinning

Crown, temples, a widening part.

Think androgenetic alopecia — usually diagnosed by examination alone.

Patchy loss

Distinct bald patches.

A different conversation — often alopecia areata.

See a doctor or dermatologist first if there isScarring or shiny skin · a sore, inflamed scalp · rapidly spreading patches · eyebrow or body hair loss · feeling unwell.

The blood test should follow the pattern, not replace it.

Educational content, not medical advice. Sudden, patchy, scarring or persistent hair loss deserves a proper medical or dermatology assessment.

Which blood tests are useful for thinning hair?

It depends on the pattern. For diffuse shedding, a full blood count with ferritin and a thyroid test (TSH, sometimes free T4) are the most commonly considered. Vitamin B12, vitamin D, zinc and hormone tests are added only when your diet, medication, symptoms or history point there.

Should I take iron, biotin or zinc supplements for hair loss?

Not blindly. Supplements help when a test shows a real deficiency. Without one, extra iron, zinc or vitamin D rarely grows more hair, and some — like high-dose zinc or biotin — can cause side effects or distort lab results.

Do I need blood tests before SMP or a hair transplant?

Density SMP doesn’t require routine bloodwork. But if your shedding is diffuse or sudden, we ask you to have it checked by your GP or dermatologist first, because planning density on an active shed gives a misleading result. Before a transplant, standard pre-operative bloods are part of the medical work-up.

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Hair Loss

Telogen vs. Anagen Effluvium — The Two Big Sudden Shed Patterns

5 min readMay 2026
Telogen vs. Anagen Effluvium — The Two Big Sudden Shed Patterns

One is reversible, one is rare and dangerous. The difference matters for your timeline, your bloodwork, and whether to operate.

Two Mechanisms, Very Different Stakes

Both telogen effluvium and anagen effluvium look the same to a panicking patient: a sudden surge in hair shedding, often visible in the shower drain, on the pillow, or in the brush. The mechanism behind each — and the appropriate response — is completely different.

Telogen Effluvium — The Stress Trigger

In healthy adults, around 10–15% of follicles are in the resting (telogen) phase at any time. A major stressor — illness, surgery, severe diet, childbirth, divorce — pushes a much larger fraction into telogen at once. About 2–4 months later, all those follicles shed together.

Telogen effluvium is almost always reversible. Once the trigger passes, follicles re-enter the growing phase. Recovery takes 6–12 months.

Anagen Effluvium — Direct Toxicity

Anagen effluvium is shedding from follicles still in the growing (anagen) phase. The follicle has been directly damaged — most commonly by chemotherapy, radiation, or severe heavy-metal toxicity. Onset is rapid (within weeks), shedding is dramatic, and the cause is usually obvious.

Recovery depends on the cause. Post-chemo regrowth typically begins 3–6 months after treatment ends and reaches 80% of normal within a year.

Which One Are You Looking At?

Three quick signals separate the two:

  • Onset speed: telogen is delayed (months after the trigger); anagen is immediate (weeks)
  • Hair characteristics: telogen sheds full-length hairs with white club roots; anagen sheds tapered, broken, dystrophic shafts
  • Trigger profile: telogen comes after life stress, illness, or hormonal change; anagen almost always has a chemical or radiation cause

When to Get Bloodwork

For any unexplained shedding lasting more than 8 weeks, get tested: ferritin, full thyroid panel, vitamin D, B12, zinc. Many telogen effluviums are partly nutritional and resolve faster once the underlying deficiency is corrected.