How Confounders Can Undermine Clinical Trials

When your brand invests in a clinical trial, whether for a cutting-edge skincare serum, a gut health supplement, or a pet wellness product, you’re looking for one thing: results you can stand behind with confidence. But lurking beneath even the most well-planned studies are hidden forces called confounders that can quietly distort your outcomes.

If confounders aren’t properly managed, your product could appear more effective, or less effective, than it actually is. This can lead to misleading marketing claims, regulatory backlash, or worse, loss of consumer trust.

What Are Confounders?

A confounder is an external variable that influences both the independent variable (your product) and the dependent variable (the outcome being measured). This can distort the relationship between your product and the desired effect, making the results look better (or worse) than they truly are.

Simple Example

If you conduct a trial on a sleep supplement, but some participants also start practicing meditation during the study, meditation becomes a confounder, it independently improves sleep and can falsely enhance your product’s perceived effects.

Why Confounders Matter for Non-Pharmaceutical Clinical Trials

In non-pharmaceutical clinical trials, confounders are especially important because lifestyle factors, cosmetic routines, and supplement use are often less controlled than in drug studies.

1. Influence on Product Claims

Your brand’s clinical trial might support claims like:

• “Clinically tested to reduce fine lines”

• “Promotes better digestion”

• “Supports pet joint health”

But if confounders aren’t controlled, these claims could lack validity, leading to consumer mistrust or FTC scrutiny.

2. Regulatory Expectations and Legal Risks

Agencies like the FTC require marketing claims to be backed by rigorous scientific evidence. If trial results are influenced by unaccounted confounders, your claims could be seen as deceptive, opening the door to legal action or required corrective advertising.

3. Brand Reputation and Consumer Loyalty

Modern consumers care deeply about scientific transparency. Publishing trial results that clearly address confounders not only strengthens marketing claims but also builds long-term brand credibility.

Common Confounders to Watch For

Confounders can sneak into your trial in many ways. Here are the most common culprits:

Lifestyle Factors

• Sleep patterns

• Exercise habits

• Stress levels

• Diet and hydration

• Sun exposure (skincare trials)

Concurrent Product Use

• Other supplements

• Skincare or cosmetic products

• Medications (if applicable)

• Pet foods and vitamins (in pet trials)

Demographic Variables

• Age

• Gender

• Socioeconomic status

• Genetic predisposition

How to Identify Potential Confounders Before a Trial

Proactively identifying confounders starts during the trial design phase:

• Conduct a risk analysis to identify factors that could influence your outcome variable.

• Review published literature to understand what variables typically influence the outcome in your product category.

• Consult experienced clinical researchers to uncover unexpected confounding variables based on similar past studies.

How to Control for Confounders in Clinical Trials

Managing confounders requires methodological rigor. Here’s how to control for them:

1. Randomization

Randomly assign participants to treatment and placebo groups to balance confounders across both groups.

2. Blinding

Use double-blind or single-blind designs so participants and researchers can’t unintentionally bias outcomes.

3. Screening and Exclusion Criteria

Use strict inclusion/exclusion criteria to screen out participants whose lifestyle factors or product use could skew results.

4. Standardizing External Factors

Control external factors where possible. For example, in skincare trials, provide all participants with a basic moisturizer and restrict use of other products during the trial.

5. Statistical Adjustment

Use multivariate analysis or regression modeling during data analysis to adjust for remaining confounders that couldn’t be controlled during the trial.

Why Transparent Reporting of Confounders Matters

Even with careful trial design, no study is immune to the influence of confounders. That’s why it’s vital to:

• Acknowledge potential confounders in your study report

• Detail how you managed them

• Disclose any limitations

Transparent reporting builds trust with regulators, the scientific community, and consumers. It signals that your brand values honest science, not just favorable results.

Smart Brands Address Confounders Before They Undermine Results

Confounders may seem like a small detail, but in reality, they can make or break the credibility of your clinical trial and your product claims.

By designing your study carefully, controlling for confounders, and transparently reporting your methods, you’ll produce results that:

• Stand up to regulatory scrutiny

• Support bold but truthful marketing claims

• Build long-term consumer trust

In today’s competitive wellness, beauty, and pet health markets, the brands that prioritize scientific rigor, and understand the impact of confounders, will come out ahead.

Looking to conduct a scientifically-sound clinical trial? Learn more about how we conduct customized clinical trials here at Citruslabs.