Liquid Collagen + Biotin is a supplement sold by Zena Nutrition. The company claims their supplement "supports skin elasticity, hair strength, and nail health."

But does Zena Collagen and Biotin contain a research-backed collagen dose? Is biotin clinically shown to improve skin and nails? Does this drink contain any unhealthy additives? And is it better or worse than popular collagen supplements like Vital Proteins?

In this article we'll answer all of these questions and more, as we analyze the ingredients in Zena Liquid Collagen + Biotin to give our take on whether or not it's likely to be effective for improving skin quality, and whether or not it's healthy.

We'll also share our concerns about its packaging, and compare Zena Liquid Collagen to other popular collagen supplements to pick our winners.

Key takeaways:

• Contains four inactive ingredients we consider unhealthy
• Packaged in plastic
• We do not currently recommend Zena Collagen + Biotin

Ingredient Analysis

The active ingredients in Zena Liquid Collagen + Biotin are shown below:

Biotin is included at a 5,000 microgram (mcg) dose, and while this B-vitamin can support hair and nails, we haven't come across any clinical evidence that biotin supplementation has benefits in individuals without biotin deficiency.

Collagen is included at a 2,500 milligram (mg) dose, and this is within the effective dosing range for promoting skin health and anti-aging.

The inactive ingredients in this supplement are shown below:

image source: Amazon.com

We apologize for the low quality of this image. Zena doesn't appear to clearly publish inactive ingredients on their product page, so we had to pull this image from the Amazon listing.

Citric acid is clinically shown to be inflammatory in some individuals, as we documented in our NativePath Collagen reviews article.

Natural flavor is a better option than artificial flavor, but still may have some questionable compounds according to a medical review published in the Environmental Health Perspectives journal.

Sodium benzoate and potassium sorbate are synthetic preservatives, and this category of food additives may have negative effects on physical and mental health, according to a 2024 medical review.

Overall, we consider Zena Liquid Collagen + Biotin somewhat likely to be effective for anti-aging, given the research-backed collagen dose, but we do not currently recommend this supplement due to the inactive ingredients described above.

Is the Packaging Harmful?

This liquid supplement is packaged in plastic.

It's been clinically shown that plastic-bottled drinks leach harmful contaminants into the liquid, and we consider this an even greater risk for acidic drinks.

Malic acid and citric acid increase the acidity of this drink.

Acidic drinks may cause greater leaching of contaminants from plastic bottling, as we documented in our Dr Kellyann bone broth reviews article.

We generally recommend avoiding drinks bottled in plastic.

Particularly in the case of drinks consumed for health, the potential downsides seem to outweigh most benefits in our view.

Zena Collagen vs. Popular Collagen Brands

Here's how Zena Liquid Collagen + Biotin compares to other popular collagen supplements in terms of potential effectiveness and healthiness, in our opinion:

Vital Proteins

One of the industry leaders for a reason; Vital Proteins offers collagen derived from grass-fed animals with no unhealthy additives in most SKUs.

Some formulations contain additional active ingredients like hyaluronic acid which was shown in a 2015 clinical trial to improve skin moisture.

Winner: Vital Proteins

Spoiled Child

Contains artificial flavors and phosphoric acid, both of which we consider to be worse for health than the inactive ingredients in Zena Collagen, as we documented in our Spoiled Child reviews article.

Winner: Zena Collagen + Biotin

NeoCell Collagen

Liquid collagen formulation contains 60% higher collagen dose (still within the effective dosing range), and contains one fewer preservative.

Winner: NeoCell Collagen

Zena Liquid Collagen Pros and Cons

Pros:

• Research-backed collagen dose
• May be good option for individuals with biotin deficiency
• No significantly harmful ingredients (like artificial sweeteners or flavoring)

Cons:

• Relatively low collagen dose (within the effective range)
• No other active ingredients we consider effective in healthy individuals
• Doesn't appear clinically tested
• Packaged in plastic
• Contains synthetic preservatives
• Contains citric acid
• Contains natural flavor

Conclusion

Zena Collagen + Biotin is an underwhelming formulation in our view.

While biotin is included in many collagen supplements, we have yet to come across any convincing evidence that it improves skin, hair or nails in individuals without a biotin deficiency.

Zena Nutrition does not appear to link to any studies proving such on their product page.

This supplement does contain a research-backed collagen dose, so we consider it likely to be somewhat effective, but this dose is at the low end of what we consider to be the effective range.

We generally recommend aiming for 10 g daily rather than 2.5 g, since collagen is such a safe supplement.

This supplement contains four inactive ingredients we consider potentially unhealthy, and it's packaged in plastic.

We consider Zena Collagen + Biotin to be a better option than Spoiled Child's liquid collagen, but an inferior option to Vital Proteins or NeoCell Collagen.