The Bump Report · UK Edition

Nearly Every Pregnant Woman In The UK Worries About Stretch Marks.
Almost None Are Told Why Cocoa Butter Never Reaches Them.

If you've walked into Boots looking for a proper stretch mark cream during pregnancy, you've probably left more confused than when you walked in. Twelve tubs. Twelve promises. None of them actually explain where stretch marks come from. Here's what dermatology researchers now know, and what a small team of mums built as a response, formulated to UK cosmetic standards, delivered across the UK with all duties covered.

Where the marks really form

Your cocoa butter smells lovely. It's just not going anywhere near the layer that matters.

This is the bit nobody explains on the tub. Stretch marks don't form on the surface of your skin. They form 3 mm below it, in a layer called the dermis. And that's the layer most belly creams sold in the UK never reach.

Here's what's actually happening under your skin from around week 20 onwards.

So when you smooth on your belly butter at night, it sits on the epidermis. Feels lovely. Smells lovely.
And never gets anywhere near the dermis where it needs to be.

The one ingredient dermatology took seriously

After decades of testing cocoa butter, researchers went looking somewhere else.

The Cochrane review was published in 2012. It should have ended the belly butter industry. It didn't. But it did push a small group of dermatology researchers to look at something different. A botanical extract used in traditional Asian medicine for centuries, now sitting in the shortlist of ingredients that actually showed something interesting in the lab.

Here's what the published research on concentrated Centella Asiatica extract shows it can do inside the skin:

Ref: MDPI Cosmetics Journal, 2024. "The Natural Centella asiatica Extract Acts as a Stretch Mark Eraser: A Biological Evaluation."

The trial that changed the conversation

Eighty pregnant women. Two groups. Nobody knew who got what.

In a published clinical trial, eighty pregnant women were randomly split. Half received a cream containing concentrated Centella Asiatica extract. The other half received a placebo cream that looked, felt, and smelled the same. Neither the mums nor the researchers knew who got which one, that's what "double-blind" means, and it's what makes results trustworthy.

They kept it up through pregnancy. Then someone counted.

Nearly a third fewer stretch marks in the Centella group. And here's the bit that made the researchers write it up: among the women who were already genetically predisposed to marks, so the mums whose own mothers had them, the difference was even bigger.

We're not going to pretend BellyBloom Elixir replicates this exact trial. What we can tell you is that our formula is built around the active ingredient the trial studied, at meaningful concentration. Individual results vary. Genetics are the strongest single predictor. What we ask is this: use it every day for 90 days as directed. If your skin doesn't feel it's had the support it needs, one email and we refund. Every penny. No form, no interrogation, no questions.

The trick to look out for

You'll see Centella Asiatica on lots of labels now.
Very few of those creams actually contain a meaningful amount.

Once a paper like the Centella trial gets published, the industry catches on. Fast. In the last two years Centella has become the "buzz" ingredient at Boots, Superdrug, and every other pregnancy skincare aisle in the UK.

Here's the catch, and it's an important one to know if you're paying £22 for a jar. Most of these creams contain around 1 to 2% Centella. The clinical trials that showed real cellular activity used concentrated extract, not a trace amount tucked at the bottom of the ingredient list. It's the difference between a splash of coffee in a bucket of water, and an actual espresso.

Under EU and UK cosmetic law, ingredients on the back of the packaging are listed in order of concentration. If Centella Asiatica is the third-to-last ingredient on the label, before "parfum" and "preservatives", you're paying for water with a hint of green.

This is bigger than skin

It isn't about the marks. It's about how you feel when nobody's looking.

A 2021 study out of Michigan Medicine asked 116 pregnant women what worried them most about how pregnancy would change their body. They expected weight to top the list. It didn't. Stretch marks did. And when they dug into why, the researchers found something they hadn't expected.

Pregnancy should feel like a season of quiet confidence.
Not a slow anxiety about the mirror at 3 a.m.

The question every UK mum asks

"My mum got them. Doesn't that just mean I will too?"

Honest answer: yes, genetics matter. A lot. Your mum having stretch marks is one of the strongest predictors that you might get them too. We're not going to pretend otherwise. Any brand that does is lying to you.

But here's what genetics actually determine. They set the baseline elasticity of your skin fibres. What they do not determine is whether those fibres get any support during the months of rapid stretching. Think of teeth. Some people are genetically prone to cavities. That doesn't mean brushing is pointless. It means daily support matters even more if the odds are stacked.

And here's the thing about the Centella trial we found interesting: the sub-group where the biggest difference emerged wasn't the low-risk mums. It was the predisposed ones. Which doesn't mean it will work for you personally, genetics are complex, and no cream can rewrite them. But it does mean not writing yourself off before trying might be worth it.

What UK mums are saying

Their words, not ours.

Belly Bloom vs the tub you already have

The clean formulation difference, side by side.

The questions we get most

Straight answers, no fluff.