From Claims to Proof: The New Era of Biostimulants
The biostimulant market has a trust problem. Not universally and not without reason for optimism – but the problem is real, well-documented and the industry is challenged to address it.
A 22-state study published in early 2026, testing seed-applied biological products across 103 field locations in the United States, found that the products didn’t show consistent yield improvements in soybeans. The researchers were careful to note that the study didn’t prove that biostimulants don’t work under any conditions. What it did demonstrate is that broad marketing claims don’t hold up when tested at scale across real growing environments, without the filter of company-funded data.
That finding wasn’t a surprise to anyone paying close attention. It was a confirmation of a problem the industry has been circling for years: the gap between what products claim and what independent evidence supports.
The gap is closing. Not simply because producers have suddenly become more transparent, but because the regulatory and commercial environment is making unsupported or poorly substantiated claims increasingly expensive to maintain.
What Regulation is Actually Requiring
The clearest signal of what’s coming is the EU’s Fertilising Products Regulation (Regulation 2019/1009), which came into force in July 2022. It was the first time any governing body formally defined plant biostimulants as a distinct product category – separating them legally from fertilisers and crop protection products – and attached specific evidence requirements to the definition. Under the framework, any claim made for a CE-marked (European Conformity) biostimulant must be substantiated with evidence of efficacy. Products seeking CE marking must go through a conformity assessment process involving a notified body. Five European technical specifications – the CEN/TS (European Committee for Standardization / Technical Specification) 17700 series – define what constitutes a valid biostimulant claim, what trial design is required to support it and what documentation and record-keeping standards apply.
In plain terms: if you want to sell into the EU market under a harmonised CE mark, you need data. Peer-reviewed, statistically demonstrated, trial-design-validated data. A label and a sales deck are no longer sufficient.
The EU is not alone in moving in this direction. In the United States, the Plant Biostimulant Act – reintroduced in 2025 – aims to establish a federal definition and create a dedicated regulatory pathway separate from the EPA (Environmental Protection Agency) pesticide rules, which currently govern any product making growth-regulating claims. California moved first at the state level, implementing the AAPFCO (Association of American Plant Food Control Officials) Uniform Beneficial Substances Bill in 2025. India’s Ministry of Agriculture introduced its own biostimulant framework in May 2025, bringing the category into formal regulation for the first time. The direction of travel across major agricultural markets is consistent: definitions are tightening and evidence requirements are following suit.
Why Growers Should Care About This Shift
Regulatory compliance is a producer’s problem. But what it produces is a grower’s benefit.
For most of the biostimulant market’s history, growers have had limited tools to evaluate products beyond manufacturer data, agronomist recommendations and their own trial and error. The products making the most claims have often been the ones with the least to substantiate. The absence of a regulatory framework meant there was no floor on the quality of evidence required to make a claim – and no ceiling on the claims themselves.
As frameworks tighten, that changes. Products that meet the evidence requirements will have demonstrated efficacy under defined conditions. Products that can’t meet those requirements will face increasing difficulty accessing the markets that enforce them. The natural consequence is a cleaner, more credible shelf – one where the presence of a product tells the grower something meaningful about what it’s been through.
The US certification programmes emerging in parallel – The Fertilizer Institute’s Certified Biostimulant Program and the WinField United BioVerified Designation – reflect the same shift happening at the commercial level ahead of federal legislation. Both programmes evaluate products against defined performance criteria through third-party assessment. Both are, according to industry commentary, becoming increasingly important to retailers and distributors who have learnt, at their own commercial cost, what happens when they recommend a product that doesn’t deliver.
The Evidence Gap is Bigger Than it Looks
There’s a subtlety to the evidence problem that’s worth understanding. It’s not just about whether a product works or doesn’t work. It’s about the conditions under which it works, the application strategy required and whether the claims made accurately reflect the actual mechanism of action. A seaweed biostimulant applied at the wrong crop stage, at the wrong rate, to a crop under active stress rather than being prepared for stress, may genuinely produce no measurable response. That’s not evidence that the product is ineffective. It’s evidence the product was used incorrectly – but if the marketing never specified the conditions under which efficacy was demonstrated, the grower has no way to know the difference.
This is why the EU’s CEN/TS 17700 standards require not just evidence of efficacy, but evidence of efficacy under defined and documented conditions, with clear claim boundaries. A product that works on tomatoes under moderate drought stress, applied at the early vegetative stage, should say so. A claim that it improves yield and quality across all crops in all conditions is a different claim entirely – and one that requires substantially broader evidence and may be difficult to substantiate across diverse multi-location, independent trials.
Growers who have felt burnt by biostimulants that didn’t perform as expected may not necessarily have been sold bad products. They were sold imprecise claims. The two aren’t the same, but they produce the same outcome: lost money and lost confidence.
What This Means When Evaluating Products Now
The regulatory frameworks are still maturing in most markets. CE marking in the EU is available but not yet mandatory for all products. The US federal pathway is in progress. In that transition period, growers can’t yet rely on regulatory status alone as a quality filter.
What they can do is apply the same logic that emerging frameworks are built on:
- Ask for trial data that’s independent, multi-location and where available, peer-reviewed or publicly accessible – not just internal efficacy summaries
- Ask which crops the data covers, under what conditions and at what application timing – a claim without those specifics is an incomplete claim
- Ask whether the product’s mechanism of action is described in terms that align with published science – not marketing language dressed up as biology
- Ask what the producer’s own trials programme looks like and whether results are made available, including where performance was variable or inconclusive
That last point matters. A producer willing to share data where the product didn’t perform as expected is telling you something important about how they approach evidence. A producer whose published data shows only positive outcomes across all crops and all conditions probably has a data selection problem.
The Market Rewards What Regulation Enforces
The biostimulants sector is growing – market projections consistently put it on a trajectory towards $7–8 billion globally by 2030. But capital is becoming more selective. As one recent industry analysis noted, venture capital (VC) funding to biostimulants dropped sharply in 2024, with commentary pointing to terminology noise, overcrowded offerings and the difficulty of distinguishing credible products from aspirational ones.
The market is recalibrating. Story-led selling is giving way to evidence-led adoption. The products that’ll define the next decade of biostimulant use won’t be the ones with the boldest claims. They’ll be the ones whose claims are the most precisely scoped, the most consistently validated and the most honestly presented.
For growers, that’s a better market to buy in. For producers building products on genuine science, traceable raw material and independently validated performance, it’s the market they were always building for.
Image Credit: Magnific Image Generator (Prompted & Reviewed by Karma Kelp)
