SkinBioTherapeutics has not explicitly disclosed a £750k Zenakine royalty figure in its FY25 accounts, with commercial terms remaining confidential. However, the CEO has publicly acknowledged that straightforward arithmetic using figures in the annual report allows this amount to be inferred as attributable to Zenakine royalties.

At first glance, a number in that region does not look transformational. In public-market terms, it barely moves the needle. That reaction is understandable. It is also incomplete.

Royalty Income

The implied royalty figure is not consumer revenue. It is not Croda’s revenue. It is not even the full value of Zenakine sold into the market.

It is a royalty skim taken several steps upstream in a business-to-business supply chain. Numbers at that level behave very differently from the figures most investors are used to interpreting.

The question is not whether the implied amount is “big”, but what it represents.

Royalty Mechanism

Royalty income from Zenakine is paid by Croda to SkinBioTherapeutics based on Croda’s sales of the ingredient to its customers. The commercial terms are confidential, though management has described the royalty rate as “double digit”.

At a basic level, the relationship is simple: royalty income equals Croda’s Zenakine sales multiplied by the royalty rate. If “double digit” is taken to mean roughly 10–15%, then an implied royalty figure of around £750k corresponds to approximately £5–7.5m of Zenakine sold by Croda to brands and formulators.

That figure still does not represent consumer sales. It is the value of an input — one line item in a formulation — sitting several layers upstream from a finished product on a shelf.

Ingredient Economics

Cosmetic and personal-care actives are typically used at very low inclusion rates, often fractions of a percent. That creates leverage.

A relatively small amount of ingredient can underpin a very large amount of finished product. One tonne of active used at a 1% inclusion rate supports roughly 100 tonnes of final formulation. Depending on pack size, that can translate into hundreds of thousands or millions of units.

This does not mean those units exist today, or that they are selling through. It means that upstream ingredient revenue can correspond to far more downstream activity than its headline size suggests.

To make that relationship more concrete, the calculator below allows readers to vary a small number of assumptions and see what kind of downstream scale is implied.

A Sense of Scale

The calculator is not a forecast. It does not tell us how fast Zenakine will grow, how sticky customers will be, or whether any particular product will succeed at retail. It does something narrower.

It translates upstream royalty income into a rough sense of physical scale. Under a wide range of conservative assumptions, the result is the same: the activity implied by the royalty figure sits comfortably in commercial territory. This is not lab work. It is not a single brand trial. It is ingredient flow at a level that fits Croda’s normal operating model.

That matters because ingredient economics are easy to misread. A number that looks small in public-market terms can still represent meaningful manufacturing and formulation activity when it sits several layers upstream.

Multiple Customers

One instinctive reaction is to assume that this sort of royalty income must come from one or two large global brands. That is possible, but it is not the default pattern in ingredient markets.

Croda sells to thousands of customers globally. Adoption often spreads horizontally rather than vertically: many smaller brands incorporating the same active across niche or regional products, rather than a single blockbuster SKU doing all the work.

In practice, a few anchor customers, a long tail of smaller brands, and a steady churn of new formulations is a perfectly normal outcome. Nothing in the implied scale requires Zenakine to already be a winner-takes-all ingredient. It only requires it to be useful, credible, and available.

Continued Marketing

Croda is continuing to showcase Zenakine at industry events, including listing it prominently among its active ingredients. That is a small signal, but it is not a meaningless one.

If Zenakine were truly experimental, it would sit in technical papers and background discussions, not front-line marketing. If it were fully mature, Croda would not need to keep highlighting it.

That places Zenakine in a middle phase: launched, selling, and still being actively pushed. The science has cleared the bar. The work now is adoption, education, and distribution.

This is consistent with the royalty number being real but not definitive. It looks like early commercial traction, not end-state penetration.

Adoption Curve

It is worth being explicit about the limits.

This analysis does not tell us where Zenakine sits on its long-term adoption curve. It does not tell us whether reorder rates will hold, whether pricing power will persist, or how large the category could become over time.

It does tell us that the activity implied by the royalty figure is non-trivial. Even allowing for uncertainty around royalty tiers and pricing, the scale involved rules out token experimentation. Croda is not moving this volume for curiosity value.

In that sense, the number functions as a filter. It does not prove success. It does remove triviality from the range of plausible interpretations.

Adoption Signals Required

The picture would sharpen materially with any of the following:

• Disclosure of repeat royalty income across reporting periods, which would indicate persistence rather than launch-related noise.
• Evidence of named customer launches, particularly if they extend beyond niche or regional brands.
• Clearer signals from Croda about where Zenakine sits within its active portfolio over time, rather than at a single event.

Conversely, if marketing emphasis faded quickly or royalties proved lumpy and non-recurring, the interpretation would shift toward one-off launch activity rather than durable adoption.

Narrow Conclusion

The point is not that the implied royalty figure proves Zenakine is already a breakout success. It does not.

The point is that in a low-inclusion, high-leverage industry, upstream royalty income can correspond to far more real-world product than casual observers assume — especially when the distribution partner is built to serve a wide and fragmented customer base.

The number is not the answer. But it does rule out insignificance.