Mounjaro and hair loss

Mounjaro Hair Loss Products UK: What’s Actually Worth Buying?

No shampoo, serum or supplement has been shown to stop hair shedding on Mounjaro. It usually settles on its own. A few products can help your hair look fuller while it does, and several popular buys aren’t worth your money.

The short answer

Nothing you can buy stops the shedding, and it usually settles by itself in three to six months. Here’s where each product fits:

Toppik hair fibres: best for disguising visible thinning. They work straight away.
Nioxin shampoo: a shampoo option that helps thinning hair look fuller. It doesn’t regrow hair.
The Ordinary serum: an optional extra. We’re less confident it does much.
Don’t buy on the off chance: biotin, iron, zinc, collagen, hair gummies and red-light caps. Ask for a blood test instead.
See a GP or pharmacist if: you have bald patches, a sore, red or scaly scalp, shedding for more than six months, or you feel unwell in other ways.

The products at a glance

Swipe sideways to see the full table →

Product	Best for	Our verdict
Toppik Hair Building Fibres	Disguising visible thinning, straight away	Best first buy if thinning shows
Nioxin Hair Fall Defense Shampoo	A shampoo that helps thinning hair look fuller. Not a regrowth product	Fine if you want one, but not essential
The Ordinary Multi-Peptide Serum for Hair Density	An optional extra if you want to try a serum	Optional extra, not a fix
Watermans Grow Me Shampoo	A gentle, sulphate-free everyday shampoo	Reasonable, but ignore “growth” claims

Products worth considering

We’ve included each of these because it does something useful for people whose hair is thinning.

Before you look at products

These are everyday consumer products. They don’t treat side effects of weight-loss medicines, don’t change how those medicines work, and aren’t a substitute for advice from your prescriber, GP or pharmacist.

1. Toppik Hair Building Fibres

Best for: disguising visible thinning, straight away.

What it is: coloured fibres made from keratin, the protein hair is made of, which you shake or spray onto thinning areas. They cling to your existing hair and wash out when you shampoo.

Why we included it: it’s one of the options the British Association of Dermatologists suggests when telogen effluvium makes the scalp start to show through (BAD).

What the evidence says: there’s nothing to prove here. It’s a cover-up, and you can see whether it works in the mirror. It does nothing to the shedding itself.

What the brand says: the fibres blend with your own hair and stay in place in wind, sweat and light rain. Toppik says they’re made from keratin from wool.

Our view: if your parting or crown is noticeably thinner, this is the product most likely to make you feel like yourself again, and it doesn’t pretend to be anything else. Match the shade carefully and start with a small size.

Hair & hair loss

Toppik Hair Building Fibres

By Toppik · Sold by Toppik UK

Coloured keratin fibres you shake onto thinning areas. They cling to the hair you already have, so a see-through parting or crown looks fuller straight away. They wash out with shampoo.

May suit

Anyone whose scalp is starting to show through at the parting or crown
People who want an instant, temporary fix for an event, a photo or everyday confidence

Limitations

Cosmetic cover only: it has no effect on shedding or regrowth
Needs some hair to cling to, so it works less well on bare patches
Can rub off onto pillows and collars, and heavy rain can shift it
Made from wool-derived keratin, so check it suits you if you react to wool

Check current price at Toppik UK

Product details checked 30 September 2026 by The Peptide Brief editorial team. This is not an affiliate link. How we choose products

2. Nioxin Hair Fall Defense Shampoo

Best for: a shampoo that helps thinning hair look fuller. Not a regrowth product.

What it is: a cleansing shampoo for thinning hair, with caffeine, niacinamide (a form of vitamin B3) and a cooling mint oil.

Why we included it: dermatologists suggest a volumising shampoo for thinning hair, and Nioxin is one of the most widely sold thinning-hair shampoos in the UK. Unusually, its own product page says it’s “not a hair regrowth product”, which is refreshingly honest.

What the evidence says: there’s no published trial of this shampoo. A 2025 review of caffeine in hair products found nine small trials, only two of them in telogen effluvium, and rated most of the evidence low or very low quality (Szendzielorz and Spiewak, 2025).

What the brand says: “visibly less hair fall” after 12 weeks, and “93% of people have less hair fall”. Both are based on its own studies of 30 people, which aren’t published.

Our view: a perfectly good shampoo if you want one made for thinning hair and like the clean, tingly feel. But an ordinary volumising shampoo gives fine hair much the same lift for less. It contains sulphates, so if your hair is dry or coloured you may prefer something gentler.

Hair & hair loss

Nioxin Hair Fall Defense Shampoo

By Nioxin · Sold by Boots

A cleansing shampoo for thinning hair with caffeine, niacinamide and menthol. It removes build-up and can give fine hair more lift at the root. Nioxin's own wording is 'visibly less hair fall', and it states that it is not a hair regrowth product.

May suit

People who want a shampoo made for thinning hair and like a cool, clean-scalp feel
Fine or oily hair that goes flat quickly

Limitations

No independent evidence that it shortens shedding linked to weight loss
The brand's results come from its own unpublished studies of 30 people
Contains sulphates, which some people find drying on coloured or dry hair
Costs more than an ordinary volumising shampoo that gives similar lift

Check current price at Boots

Also sold by Nioxin UK.

Product details checked 30 September 2026 by The Peptide Brief editorial team. This is not an affiliate link. How we choose products

A sulphate-free alternative: Watermans Grow Me is a popular UK caffeine shampoo. It usually costs less than Nioxin and is sulphate-free. We haven’t given it a product card because its “hair growth” marketing goes further than its evidence, which is a self-reported survey of 122 users. As a gentle everyday shampoo, though, it’s a reasonable choice.

3. The Ordinary Multi-Peptide Serum for Hair Density (optional)

Best for: an optional extra if you want to try a serum. Our lowest-confidence pick.

What it is: a leave-in serum you massage into your scalp every day. It contains caffeine and several branded cosmetic ingredient blends. The “peptides” in the name are cosmetic ingredients applied to the skin. They have nothing to do with the injectable peptides we cover elsewhere on The Peptide Brief, and this product contains no copper peptides.

Why we included it: it’s one of the cheapest and most widely available scalp serums, and its claims are about how hair looks rather than stopping hair loss.

What the evidence says: the studies behind its ingredients are small, mostly in pattern hair loss rather than telogen effluvium, and often run with the ingredient makers. In 2022 the ASA upheld complaints about another brand’s caffeine scalp treatment containing one of the same ingredient blends, which claimed to “help stimulate growth” (ASA).

What the brand says: it improves “the appearance of hair thickness and fullness” and “visibly” improves density at the root when used daily.

Our view: an optional extra, not a fix. Because telogen effluvium usually settles by itself, you won’t really be able to tell whether it helped. If you only buy one thing, buy fibres first.

Hair & hair loss

The Ordinary Multi-Peptide Serum for Hair Density

By The Ordinary · Sold by The Ordinary

A leave-in scalp serum with caffeine and several branded cosmetic ingredient blends. The brand says it improves the appearance of hair thickness and fullness. Its 'peptides' are cosmetic ingredients applied to the scalp, not the injectable peptides covered elsewhere on this site.

May suit

People who want to try a low-cost scalp serum alongside gentle hair care
Anyone happy to use a product every day for several months to judge it

Limitations

Not shown to stop or shorten shedding linked to weight loss
Evidence for its ingredients is small and mostly in pattern hair loss
Shedding often settles by itself, so it is hard to tell whether it helped
Can leave fine hair slightly tacky; stop using it if your scalp gets irritated

Check current price at The Ordinary

Product details checked 30 September 2026 by The Peptide Brief editorial team. This is not an affiliate link. How we choose products

Before you buy anything

Don’t stop Mounjaro or change your dose because of hair loss without speaking to your prescriber. In the trials, most people’s hair recovered while they carried on with treatment. If your shedding is heavy, patchy, or comes with other symptoms, see the section on when shopping isn’t the answer first.

Why hair can shed on Mounjaro

Hair loss is listed as a common side effect of tirzepatide, the medicine in Mounjaro, when it’s used for weight management. In the pooled weight-loss trials (SURMOUNT-1, -2 and -3), hair loss was reported by 4.9% of people taking tirzepatide and 1.0% of people taking a placebo.

The official product information says the cases were mainly mild, most people recovered while they carried on with treatment, and nobody stopped the medicine because of it (Mounjaro SmPC, eMC). The NHS page on tirzepatide also lists hair loss as a common side effect.

The kind of hair loss most often linked to weight loss is called telogen effluvium. Normally about 15% of the hairs on your head are in a resting phase before they fall out. After a shock to the body, such as marked weight loss, extreme dieting, illness or surgery, that can jump to 30% or more.

The extra shedding usually shows up around three months after the trigger, comes from all over the scalp rather than in patches, and is most noticeable in the shower or on your brush (British Association of Dermatologists).

What isn’t known for certain is how much of the shedding is down to tirzepatide itself, and how much is down to losing a lot of weight and eating much less. The product information doesn’t say.

Eating less can also mean less protein and iron, and a shortfall in iron can make telogen effluvium hang around or come back. That’s why the useful questions are about how you’re eating and whether you’re low in anything, rather than which shampoo to buy.

For the wider picture on side effects, see our plain English guide to Mounjaro. We’ve also looked at what people in the community are saying about hair loss on retatrutide.

What a hair product can and can’t do

The British Association of Dermatologists says telogen effluvium usually gets completely better without treatment, and that taking medication doesn’t speed up regrowth. The shedding phase lasts about three to six months, and new hair then starts to grow (BAD patient information).

So it helps to be clear about what you’re paying for. A product can realistically:

make thinning hair look thicker or fuller (hair fibres, volumising shampoo)
reduce breakage from rough handling, heat and harsh treatments
keep your scalp clean and comfortable

No shampoo, serum or supplement has been shown to stop telogen effluvium, shorten it, or make hair grow back faster. None of the products we looked at has been tested in people on weight-loss medicines.

UK advertising rules draw a similar line. Cosmetics can’t claim to prevent or cure hair loss. Claims that a product reduces hair loss or promotes growth need robust evidence (ASA guidance). The Advertising Standards Authority has upheld complaints against hair products that claimed to help growth or reduce thinning without that evidence, including a caffeine scalp treatment in 2022 (ASA ruling). When a label says “hair fall” or “growth”, check what it’s actually promising.

For each product above we separate three things: what the evidence says, what the brand says, and our view.

What we wouldn’t rush to buy

This is where most of the money goes, and where the marketing is loudest. The key difference is between fixing a deficiency you actually have, which can help, and taking extra “just in case”, which usually doesn’t.

Swipe sideways to see the full table →

Product	Our view	Why
Biotin	Skip	Only helps a deficiency, which is rare. High doses can skew blood tests
Iron	Test first	Low iron can cause shedding, but extra iron can upset your stomach
Zinc	Only if a test shows you need it	Too much reduces the copper you absorb
Collagen	Skip for hair	Little good evidence, and it isn’t a complete protein
Hair gummies	Skip the “hair” label	A standard multivitamin is a reasonable safety net if you’re eating very little
Rosemary oil	Optional	Studied in a different kind of hair loss
Red-light caps	Not for this	Expensive, and barely studied in this kind of shedding

The detail behind each verdict:

Biotin

Biotin (vitamin B7) is the ingredient most often sold for hair, and it’s often recommended online for hair loss on Mounjaro. A review of the evidence found biotin only helped people who had a deficiency or a specific underlying condition, and that there isn’t enough evidence to support it for healthy people (Patel and colleagues, 2017). Biotin deficiency is rare. The NHS says you should get all you need from food, and that 0.9mg (900mcg) a day or less from supplements is unlikely to cause harm (NHS).

High-dose biotin can also interfere with some blood tests, including thyroid tests and the troponin test used to check for a heart attack, giving falsely high or low results (US Food and Drug Administration). If you do take it, tell whoever is taking your blood.

Our view: don’t buy biotin for Mounjaro shedding.

Iron

Iron deficiency is a recognised cause of telogen effluvium, and it can make shedding come back if it isn’t treated (BAD). That’s a good reason to get checked, not to take iron on spec. The NHS says most people get enough iron from food, and doses above 20mg can cause constipation, sickness and stomach pain (NHS). Those are already common side effects of Mounjaro.

Our view: if you have heavy periods, are very tired, eat little or no meat, or are eating very little overall, ask your GP about a blood test for iron levels.

Zinc

Zinc deficiency can cause hair loss, but it’s uncommon if you eat a varied diet. The NHS says not to take more than 25mg of zinc supplements a day unless a doctor advises it, because too much zinc reduces how much copper you absorb, which can lead to anaemia and weaker bones (NHS).

Our view: only if a test shows you need it.

Collagen

Collagen is marketed for hair, skin and nails, but there’s little good evidence that it helps hair loss. It is a protein, but not a complete one: it’s missing tryptophan, one of the building blocks your body can’t make itself. If you’re trying to eat more protein, ordinary protein foods do the job better.

Our view: not a hair product.

Hair vitamins and gummies

Hair supplements are usually a mix of biotin, zinc and other vitamins. A review of vitamins and minerals in hair loss concluded that fixing a deficiency may help, and that proper trials are still needed (Almohanna and colleagues, 2019). The same review notes that too much vitamin A can contribute to hair loss, and possibly too much selenium, so stacking several products isn’t a good idea.

Our view: if you’re eating very little, a standard multivitamin is a reasonable safety net. Ask a pharmacist. Don’t pay extra for a “hair” label.

Rosemary oil

Rosemary oil went viral after a small trial in 100 people with pattern hair loss found similar results to 2% minoxidil after six months (Panahi and colleagues, 2015). That’s a different kind of hair loss, and it hasn’t been tested in telogen effluvium. Undiluted oil can irritate the scalp.

Our view: harmless enough if you enjoy it, but don’t expect it to change weight-loss shedding.

Red-light caps and combs

Low-level light devices have reasonable evidence in pattern hair loss. A 2025 review of 38 studies included 3,098 patients, but only 17 of them had telogen effluvium, too few to draw conclusions (Perez and colleagues, 2025). The devices are expensive, and this kind of shedding usually settles anyway.

Our view: not for this.

Where protein and food fit

Hair is made mostly of keratin, a protein. When you’re eating much less than before, getting enough protein and iron gets harder. Dermatologists suggest a balanced diet that includes protein, iron-rich foods, fruit and vegetables for people with telogen effluvium (BAD). A 2025 advisory from four US obesity and nutrition societies lists excessive hair loss among the possible signs of a nutrient shortfall in people on GLP-1 medicines. It also stresses protein and strength training to protect muscle (Mozaffarian and colleagues, 2025).

In practice, that means trying to include some protein at each meal, such as eggs, yoghurt, fish, chicken, beans, lentils or tofu, even when your appetite is small. If you’re struggling to eat enough at all, tell your prescriber, and ask whether a dietitian could help. We’ve also covered muscle loss on GLP-1 medicines.

A protein shake can make it easier to reach your protein when you don’t feel like eating, but it’s food, not a hair-loss treatment. We haven’t recommended one here. We’ll cover protein products properly in a separate guide.

When shopping isn’t the answer

See a GP or pharmacist, rather than buying another product, if:

you have bald patches, or hair is breaking off in one area
your scalp is red, scaly, sore, very itchy or scarred
the shedding has lasted more than six months, or is getting worse rather than better
your parting is widening or your hairline is receding. Pattern hair loss can show up at the same time as telogen effluvium
you’re also very tired or breathless, feel cold all the time, or have heavy periods, which can point to low iron or thyroid problems
you’re being sick a lot or can barely eat or drink
hair loss is affecting your mood or confidence

A GP can often tell what kind of hair loss it is by looking, and may suggest blood tests. If there’s pattern hair loss underneath, they or a pharmacist can talk you through licensed treatments such as minoxidil. That’s a medical conversation, and we don’t sell or link to these medicines. The NHS also says a GP may be able to help with counselling if hair loss is causing you distress (NHS: hair loss), and Alopecia UK offers support.

Gentle hair care helps while you wait. Avoid harsh brushing, go easy on straighteners and hot tools, give bleaching and chemical treatments a rest, and avoid tight hairstyles.

Frequently asked questions

Does Mounjaro hair loss grow back?

Usually, yes. Telogen effluvium doesn’t damage the hair follicles. The shedding phase normally lasts three to six months and then new hair starts to grow, although it can take many months to get back to your usual thickness.

When does Mounjaro hair loss start?

Telogen effluvium typically shows up around three months after the trigger. So shedding often starts a few months into treatment, after a period of faster weight loss, rather than straight away.

Should I take biotin for Mounjaro hair loss?

Not unless a doctor finds you’re deficient, which is rare. There isn’t good evidence that biotin helps people who aren’t deficient, and high doses can interfere with some blood tests.

What’s the best shampoo for Mounjaro hair loss?

No shampoo stops the shedding. A volumising shampoo can make thinning hair look fuller, which is what dermatologists suggest. A thinning-hair shampoo such as Nioxin is fine if you want one, but it isn’t essential.

Will a hair serum stop the shedding?

There’s no evidence that it will. Serums are sold on appearance claims, and the research behind their ingredients is small and mostly in a different kind of hair loss.

Do I need to stop Mounjaro if my hair is falling out?

Don’t stop or change your dose without speaking to your prescriber. In the trials, no one stopped because of hair loss, and most people recovered while carrying on with treatment. Your prescriber can check whether anything else is going on.

Is it Mounjaro or the weight loss?

It isn’t certain. Hair loss was more common on tirzepatide than on placebo in the trials, and marked weight loss and eating less are well-known triggers for telogen effluvium. Both are likely to play a part.

Does collagen help hair loss on Mounjaro?

There’s little good evidence that it does. If you’re worried about protein, ordinary protein foods are a better place to start.

How we chose these products

We checked the current UK product information for Mounjaro, the NHS and the British Association of Dermatologists, and looked for published research on each product and its main ingredients. We only used manufacturers and retailers for ingredients, availability and the brands’ own claims. Online community discussions helped us understand what people are buying, but we didn’t treat them as evidence that anything works.

There are no affiliate links on this page. The shop links go straight to the retailer or brand, and we don’t earn anything from them. If we add affiliate links in future, we’ll say so clearly at the top of the page. Commission will never decide which products we include or the order they appear in. We don’t accept payment for coverage. Product details were checked on 30 September 2026. Products and prices change, so check the retailer before you buy.

Sources

About this page

Page reviewed 30 September 2026. Written and researched by The Peptide Brief editorial team, using the Mounjaro SmPC, NHS and British Association of Dermatologists guidance and the published studies listed above. This page is for information only and does not constitute medical advice. Always consult a qualified healthcare professional before starting, stopping or changing treatment.

How we research and fact-check →

Key facts at a glance

Hair loss is a common side effect of Mounjaro when it’s used for weight loss (up to 1 in 10 people).
In the main weight-loss trials, 4.9% of people on tirzepatide reported hair loss, compared with 1.0% on placebo.
Most people in those trials recovered while carrying on with treatment.
The usual pattern is telogen effluvium: extra shedding that starts around 3 months after a trigger such as marked weight loss.
The shedding phase usually lasts 3 to 6 months. Getting back to your usual thickness can take many months more.
No medicine or product has been shown to speed up regrowth.
There are no affiliate links on this page.

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