How many development rounds does a custom formula require?

Most custom cosmetic formulas require between three and six development rounds before they are ready for production. The exact number depends on the complexity of the formula, the specificity of the brief, and the type of ingredients involved. The sections below unpack each factor that shapes that number and what you can do to keep the process efficient.

What happens during a cosmetic formula development round?

A cosmetic formula development round is a single cycle of formulation, testing, evaluation, and feedback. In each round, the formulator creates a prototype based on the brief or the previous round’s feedback, assesses its performance, and presents it to the client for review. The client’s response then drives the adjustments made in the next round.

A typical round moves through several stages:

Formulation: The chemist selects and combines ingredients to meet the target texture, performance, and sensory profile.
Internal testing: The prototype is evaluated for stability, appearance, scent, spreadability, and other relevant properties.
Client review: Samples are shared with the client, who assesses the product against their expectations.
Feedback and briefing: The client provides structured feedback, which becomes the starting point for the next iteration.

Each round is a learning step. Even when a prototype does not meet expectations, it narrows the target and gives the formulator clearer direction for what to adjust next.

What factors influence how many rounds a formula needs?

The number of custom formula development rounds a product needs is shaped primarily by the complexity of the formulation, the clarity of the brief, and the stability requirements of the chosen ingredients. Products with multiple performance claims, unusual textures, or strict sensory requirements naturally require more iteration than straightforward formulas.

Key factors include:

Complexity of the formula: A multifunctional serum with active ingredients demands more refinement than a basic rinse-off product.
Clarity of the initial brief: Vague or incomplete briefs lead to more rounds because early prototypes may miss the mark on fundamental attributes.
Ingredient interactions: Some ingredients behave unpredictably in combination, particularly natural actives, which can affect stability or texture in ways that require additional adjustment.
Stability requirements: Products intended for long shelf life or challenging storage conditions need stability testing between rounds, which can reveal issues that prompt reformulation.
Regulatory constraints: Specific market requirements, such as those for certified organic or allergen-free products, can limit ingredient choices and complicate formulation.
Feedback quality: Precise, actionable client feedback shortens the process. Subjective or inconsistent feedback extends it.

How many development rounds are considered typical?

For most custom cosmetic formulations, three to six development rounds is the industry norm. Simpler products such as basic cleansers or single-function moisturizers often reach approval in three rounds. Complex formulas, such as leave-in treatments with multiple active claims or products requiring a very specific sensory profile, may take six or more rounds before both parties are satisfied.

It is worth noting that the number of rounds does not directly reflect the quality of the formulator. Some products are inherently more challenging to develop, and additional rounds are simply part of a thorough, honest process. Rushing through fewer rounds to save time can result in a product that underperforms or fails stability testing later, which is far more costly than one extra iteration early on.

Why do natural formulas sometimes need more rounds than conventional ones?

Natural cosmetics development often requires more rounds than conventional formulation because natural ingredients are inherently more variable and less predictable than their synthetic counterparts. Plant-derived extracts, oils, and butters can differ in composition from batch to batch depending on harvest conditions, geography, and processing methods. This variability makes it harder to achieve consistent texture, scent, and performance from the first prototype.

Several specific challenges drive this:

Limited preservation options: Natural preservative systems are generally less potent than synthetic ones, which means stability testing may reveal issues that require reformulation to maintain product safety and shelf life.
Sensory complexity: Natural ingredients often carry their own scent and colour, which can interact with other components in unexpected ways and require adjustment across rounds.
Emulsification challenges: Achieving stable, elegant emulsions without conventional emulsifiers takes more experimentation, particularly for products like creams and lotions.
Ingredient sourcing constraints: If a preferred ingredient becomes unavailable or is substituted for ethical sourcing reasons, the formula may need to be partially rebuilt.

None of these challenges make natural formulation inferior. They simply reflect the reality that working with living plant materials requires more expertise and patience than working with standardised synthetic compounds.

How can you reduce the number of development rounds needed?

The most effective way to reduce the number of product development rounds is to invest time in a detailed, well-structured brief before formulation begins. The more precisely you can describe the desired texture, performance, scent direction, and target consumer, the fewer rounds the formulator needs to spend guessing or correcting course.

Practical steps that genuinely shorten the process include:

Provide reference products: Sharing existing products that come close to your ideal gives the formulator a concrete sensory target to work toward.
Define your non-negotiables upfront: Be clear about which attributes are fixed (for example, vegan certification, specific actives, or fragrance-free) and which are flexible.
Give structured feedback: After each round, describe what works and what does not in specific terms. “Slightly too thick and not enough slip” is far more useful than “not quite right.”
Involve decision-makers early: Delays caused by internal approval chains add rounds. Having the right stakeholders review samples from round one prevents late-stage surprises.
Trust your formulator’s expertise: Pushing for ingredient combinations that are technically problematic can extend the process significantly. An experienced formulator will flag these early, and listening to that advice saves rounds.

How Rebel Nature supports your formula development process

We understand that efficient, transparent development is just as important as the quality of the final formula. At Rebel Nature, we work exclusively with natural ingredients and draw on a portfolio of over 500 carefully sourced raw materials to give your formulation the best possible start. Our process is designed to minimise unnecessary rounds without cutting corners on quality.

Here is what we bring to every custom formulation project:

A detailed briefing process that captures your product vision before the first prototype is made
In-house chemists with deep experience in natural cosmetics development, reducing trial and error from the outset
Proactive ingredient and packaging recommendations that align with your brand values and sustainability goals
Clear, structured feedback templates to make each review round as productive as possible
Flexible production capabilities for both small and large orders, so your formula can scale without starting over

Whether you are developing your first product or expanding an existing range, we are here to guide you through every stage. Explore how we work to get a clear picture of our development process, or get in touch with our team to discuss your custom formula project and take the first step toward a product you are proud of.

Frequently Asked Questions

How long does each development round typically take?

The duration of a single development round can vary depending on the complexity of the formula and the testing required, but most rounds take between two and four weeks. This includes formulation time, internal stability and performance testing, sample preparation, and shipping to the client for review. Rounds involving stability testing for preservation or emulsion integrity may take longer, as certain tests require several weeks of observation before results are conclusive.

What should I include in my formulation brief to avoid unnecessary rounds?

A strong brief covers six key areas: the product type and format, the target consumer and their skin or hair concerns, the desired texture and sensory experience, any ingredient inclusions or exclusions, regulatory or certification requirements, and reference products that approximate your ideal. The more specific you can be in each of these areas, the more accurately your formulator can hit the target from round one. Including mood boards, competitor products, or even descriptions of what you do not want can be just as valuable as describing what you do.

Can I make major changes to the formula brief mid-development without resetting the round count?

Significant changes to the brief mid-development — such as switching the product format, adding new active claims, or changing the preservation system — will effectively require the process to restart, as the formulator must work from a fundamentally different starting point. Minor adjustments within an existing round, such as tweaking a fragrance level or adjusting viscosity, are a normal part of iteration. To avoid costly resets, it is best to finalise your core requirements before the first prototype is made and flag any potential changes as early as possible.

What happens if a formula passes client approval but later fails stability testing?

If a formula is approved by the client but subsequently fails stability testing — for example, showing separation, discolouration, or microbial contamination — it will need to go back into development for reformulation. This is one of the main reasons why stability testing should be integrated throughout the development process rather than left entirely to the end. Working with an experienced formulator who conducts preliminary stability checks between rounds significantly reduces the risk of late-stage failures that are both time-consuming and costly to resolve.

Is it possible to develop a natural formula in fewer than three rounds?

Yes, it is possible, though it is relatively uncommon for fully custom formulas. Achieving approval in one or two rounds typically requires an exceptionally detailed brief, a straightforward product format, and a client who has clear and consistent expectations from the outset. It is more realistic for products that closely follow a well-established base formula with minor adjustments than for entirely new concepts. Rather than aiming to minimise the number of rounds at all costs, focus on making each round as productive as possible — that approach leads to the best outcome in the fewest iterations.

How do I give useful feedback after reviewing a prototype sample?

Effective feedback is specific, comparative, and covers each sensory and performance attribute separately. Instead of general impressions, evaluate the prototype across individual dimensions: texture on application, absorption speed, finish, scent strength and direction, colour, and any performance results you can observe. Where possible, compare it directly to your reference products and describe the gap — for example, ‘the texture is closer to Reference B than Reference A, but the finish is too greasy compared to both.’ Avoid vague language like ‘not quite right,’ as this gives the formulator little actionable direction for the next round.

At what point in the development process should I start thinking about packaging?

Packaging decisions should ideally be made in parallel with formula development, not after it, because the two are closely interconnected. The choice of packaging material, pump mechanism, airless versus open-jar format, and tube versus bottle can all affect formula stability, preservation requirements, and application experience. For example, a formula developed for an airless pump may behave differently in a jar, and some natural formulas are sensitive to light or air exposure in ways that dictate specific packaging choices. Raising packaging considerations from the first development round helps avoid reformulation later.