How Long Do Clinical Trials Take?

If you are considering a clinical study for a health, wellness, or CPG product, one of the first questions you will ask is how long it will take. Timelines affect product launches, marketing plans, and regulatory confidence. Understanding what actually drives clinical trial length helps brands set realistic expectations and avoid costly surprises.

Clinical trials typically take anywhere from 3 months to 2 years, depending on the study design, product type, and operational complexity. Simple consumer studies can move quickly, while more rigorous or regulated trials require longer timelines for planning, execution, and analysis.

How Long Do Clinical Trials Take on Average?

Most brand-led clinical trials fall between 12 and 24 weeks from kickoff to final results. That range covers a wide variety of study types used in health and wellness research.

Typical timelines include:

• Simple consumer perception or usability studies: 4 to 8 weeks

• Short-Term efficacy studies: 8 to 16 weeks

• Longer-Term outcome or safety studies: 6 to 12 months or more

At Citruslabs, many functional food, supplement, and personal care studies are completed in under 6 months when the scope is clearly defined from the start.

What Factors Affect How Long a Clinical Trial Takes?

Clinical trial timelines are driven more by design choices than by the product itself. Several factors can speed things up or slow them down.

Does Study Design Impact Clinical Trial Length?

Yes. Study design is the biggest driver of timeline. Key design elements include:

• Number of participants, such as 30 vs 150 people

• Study duration, such as 14 days vs 12 weeks

• Number of study visits or check-ins

• Use of at-home data collection vs in-clinic visits

For example, a 60-person, 4-week at-home study can often launch within 3 to 4 weeks and finish data collection within a month.

How Does Recruitment Affect Trial Timelines?

Recruitment can add weeks or months if not planned carefully. Factors that affect recruitment speed include:

• Narrow eligibility criteria

• Hard-to-reach populations

• Geographic requirements

Well-defined consumer studies using digital recruitment often enroll fully within 2 to 4 weeks.

Do Regulatory or Ethical Reviews Slow Things Down?

They can, but they are often predictable. Most studies require ethics or IRB review, which typically takes:

• 1 to 2 weeks for straightforward consumer studies

• 3 to 6 weeks for more complex protocols

Clear documentation and experienced study management help prevent delays.

How Long Do Different Types of Clinical Trials Take?

Not all clinical trials are the same. Brands often use different approaches depending on their goals.

Observational vs Interventional Trials

Study Type	Typical Timeline	Best For
Observational	4 to 10 weeks	Claims support, insights, early validation
Interventional	8 weeks to 12 months	Efficacy, performance, differentiation

An observational study might track consumer-reported outcomes over 21 days, while an interventional trial may require a 12-week product regimen.

When Should You Plan for a Longer Clinical Trial?

Longer trials make sense when credibility and depth matter most. You may need a longer timeline if:

• You are measuring long-term outcomes like skin changes or metabolic markers

• You want to support stronger marketing or retailer claims

• You plan to publish or share results publicly

For example, a 90-day study with 100 participants can provide more robust evidence than a 14-day pilot.

When Should You Avoid a Long Clinical Trial?

Long trials are not always necessary and can slow momentum. Shorter studies may be better if:

• You need early validation before scaling

• You are testing product concepts or formulations

• You want directional data for internal decisions

A 4-week study with clear endpoints often delivers actionable insights without over-investing.

What Are Common Mistakes That Extend Clinical Trial Timelines?

Most delays are preventable. Common issues include:

• Overcomplicating the protocol

• Adding endpoints that are not tied to decisions

• Underestimating recruitment challenges

• Changing scope mid-study

Clear goals and upfront planning help keep timelines on track.

How Should Brands Plan Around Clinical Trial Timelines?

The best approach is to work backward from your business goal. Examples include:

• If you need results for a Q4 launch, start planning 4 to 6 months earlier

• If claims are tied to packaging updates, allow extra time for review and interpretation

• If speed matters, prioritize at-home and digitally managed studies

At Citruslabs, studies are designed to balance scientific rigor with real-world brand timelines.

Key Takeaways on How Long Clinical Trials Take

• Clinical trials usually take 3 months to 2 years, with many brand studies finishing in under 6 months

• Study design, recruitment, and review processes have the biggest impact on timing

• The right timeline depends on your goals, not just your product

Define what decisions the study needs to support, then choose a clinical approach that delivers credible evidence without unnecessary delays. Don’t know which type of study to run? Try CitrusMatch today for free and get your ideal study design in under 2 minutes.