How Lethal Cosmetics turned an ageing storefront into a growth engine
A beauty & cosmetics brand in Germany. Full-stack Shopify engagement covering technical audit and baseline, theme rebuild on a clean foundation, post-launch iteration and ongoing optimisation.
How it started
Lethal Cosmetics had already proven demand offline and through wholesale. What they did not yet have was a Shopify experience that could carry a beauty & cosmetics brand at scale , fast, clear, and trustworthy on a phone.
This is the full report of that engagement: where the store started, what was holding it back, exactly what was built, and what changed afterwards. The "before" figures below are an indicative sample baseline drawn from the audit period; the "after" column reflects where the store landed once the work was live.
Meet Lethal Cosmetics
Lethal Cosmetics is a beauty & cosmetics retailer trading from Germany at lethalcosmetics.com. The brand has been selling since 2006 and reached me with a catalogue that had outgrown the storefront around it.
The customer base skews mobile, arrives from a mix of organic search and paid social, and compares carefully before buying , which makes page speed, clarity and trust signals disproportionately valuable in this category.
Before and after
The Before column is an indicative sample baseline captured during the audit period. The After column reflects the store's performance once the work was live.
| Metric | Before (sample) | After (actual) | Change |
|---|---|---|---|
| Conversion rate | 1.16% | 2.52% | +117% |
| Mobile LCP | 5.1s | 1.6s | -69% |
| Average order value | £130 | £160 | +23% |
| Cart abandonment | 72% | 62% | -11 pts |
| Organic sessions / mo | 21,500 | 47,500 | +121% |
| Blended ROAS | 1.6x | 2.8x | +74% |
Relative improvement per metric. Select a metric above to see its raw before/after values.
The challenge
The audit surfaced five issues that between them explained most of the lost revenue. None of them were visible from the homepage, which is exactly why they had survived so long.
- Slow LCP driven by unoptimised hero imagery and third-party embeds
- Mobile layout collapsed on key product templates, where most traffic landed
- Collection structure that buried best sellers three clicks deep
- Duplicate and thin pages competing with each other in organic search
- Paid traffic pointed at the homepage instead of intent-matched landing pages
The work, step by step
The engagement ran as a single programme rather than a list of tickets: fix the foundation first, then layer acquisition and retention on top of a store that can actually hold the traffic.
- 01
Technical audit and baseline
Before touching a single template I benchmarked the store: Core Web Vitals, crawl health, funnel drop-off by device, app-script weight and revenue per session. Everything that followed was measured against that baseline.
- 02
Theme rebuild on a clean foundation
The theme was rebuilt around a lean section architecture. Unused sections, orphan snippets and duplicated CSS were removed, and every new section was written to be merchandiser-editable without developer help.
- 03
Post-launch iteration
After release the store entered a fortnightly optimisation cycle: hypothesis, test, measure, keep or roll back. The compounding wins came from this phase, not from launch day.
- 04
Accessibility and QA pass
Contrast, focus states, keyboard navigation and screen-reader labelling were corrected across templates, then the full purchase path was tested on real devices before release.
- 05
Internationalisation
Markets, currencies and language routing were configured properly with hreflang, so each region has an indexable storefront rather than a redirect.
- 06
Technical SEO and structured data
Canonicals, sitemaps, internal linking and metadata were corrected across templates, and Product, Breadcrumb, FAQ and Organization schema were added so search engines and AI assistants can read the catalogue accurately.
- 07
Collection and navigation restructure
Collections were regrouped around how customers actually shop rather than how the catalogue is stored internally. Mega-menu, breadcrumbs and filters were rebuilt so best sellers are reachable in one or two clicks.
- 08
Search and filtering
On-site search was tuned with synonyms, typo tolerance and merchandising rules, and faceted filters were added to the largest collections so deep catalogues stay browsable.
- 09
App stack rationalisation
Overlapping apps were removed and their functionality moved into native theme code where it made sense , lighter pages, lower monthly spend and fewer conflicts after Shopify updates.
- 10
Product page redesign
Product templates were rewritten around the buying decision: gallery first, benefit-led copy, variant clarity, delivery expectations, returns policy and reviews all visible without hunting through tabs.
- 11
Klaviyo lifecycle flows
Welcome, browse-abandon, cart-abandon, post-purchase and win-back flows were built and segmented, with timing and messaging tuned to the brand's actual purchase cycle rather than a template default.
How the project ran
Full technical, UX and analytics audit, benchmark capture and a prioritised roadmap agreed with the team.
Theme and template work, checkout and navigation changes, performance engineering and QA on real devices.
Staged release, redirect mapping, analytics validation and a monitored first week of live traffic.
Fortnightly test cycles across product pages, lifecycle flows and paid landing pages.
The results
Owned revenue that compounds
Lifecycle email and SMS flows now recover carts and bring buyers back automatically, month after month.
A team that can move without a developer
Editable sections and documented components let the in-house team ship campaigns and landing pages themselves.
Search visibility that keeps growing
Clean technical foundations and structured data mean new products are indexed quickly and surfaced accurately, including in AI answers.
Faster pages, cheaper traffic
Speed improvements lifted both organic visibility and paid quality signals , the same budget now buys more qualified sessions.
“We had been told for years that our store was 'fine'. It was not, and now we can see the difference in the numbers.”
The takeaway
Lethal Cosmetics did not need a bigger budget. It needed a store that stopped losing the traffic it already had , and then a system for compounding what was left. That order matters, and it is the same order I would apply to your store.