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Breaking Science News:
Fixing C15:0 Deficiencies Helps Slow Aging

C15:0 Look-Alike Supplement? Here’s What to Look Out for - and 7 Questions to Ask

Published by Dr. Venn-Watson
July 19, 2023
Dr. Eric Venn-Watson’s Highlights

    • You have likely heard about the many science-backed health benefits of C15:0 (aka pentadecanoic acid)
    • Fatty15's team of doctors spent years developing fatty15 as a pure, award-winning and science-backed C15:0 supplement.
    • If you find look-alike C15:0 supplements, here are 7 key questions you should ask of them, including the presence of other ingredients that can block C15:0's benefits.
    • Fatty15 is the first and only C15:0 supplement you can trust to deliver the highest quality ingredient and peer-reviewed science to your cells.

Pictured above: Left: Gundry MD C15 Advantage supplement with numerous proinflammatory oil-based contents and plastic scent tab. Right: Fatty15, an award-winning, science-backed, and pure free fatty acid C15:0 powder supplement.

If you’re reading this, then you have likely heard about the science-backed health benefits of C15:0 (aka pentadecanoic acid), including how C15:0 helps to repair cells and promote our long-term health and wellness.

Upon discovering C15:0 as the first essential fatty acid to be found in 90 years, fatty15’s husband-wife, military family founders team of doctors spent years to develop fatty15 as a pure, patented, bioavailable, award-winning and science-backed C15:0 supplement. Check out fatty15’s origin story, which is a TEDx talk

Copying can be the best form of flattery, and an outsider has hopped on the C15:0 train to promote his own product. Our customers have asked how this product compares to fatty15, so we put together a blog that not only provides answers about fatty15, but also offers a list of helpful questions you should ask of any product claiming to provide C15:0’s health benefits.

Questions to Ask of Supplements Claiming to Have C15:0 Benefits

Question 1: Does your product contain only pure, free fatty acid C15:0?

Only pure, free fatty acid C15:0 has been shown in peer-reviewed studies to do the following:

As such, only products containing pure, free fatty acid C15:0 powder have the science to back these cellular benefit claims. 

Fatty15: Contains only one ingredient, pure, free fatty acid C15:0 powder. Every batch is third-party tested for 98.5% pure C15:0.* 

Other product: Contains many ingredients, including an oil-based C15:0 in a triacylglyceride form. Further, only 13% of this product is C15:0 (87% are other ingredients - see below). Other ingredients include a modified food dextrin complex, wax, and vanilla concentrated essence. This specific formulation has no peer-reviewed studies demonstrating cellular benefits.*

Question 2: What daily dose of your product is needed to achieve active circulating C15:0 levels?

Peer-reviewed studies have consistently shown that C15:0 concentrations of greater than 20 µM are optimal to achieve C15:0’s cellular benefits. 

Fatty15: Based on peer-reviewed human clinical trials using pure free fatty acid C15:0 powder, a 100 mg dose of pure free fatty acid C15:0 is expected to raise circulating C15:0 levels from a baseline of 10 µM to 20 µM. This is why 1 to 2 fatty15 capsules (100 to 200 mg) are recommended per day.

Other product: Studies on the bioavailability of oil-based C15:0 in a triacylglyceride form in this product’s formulation are not in the peer-reviewed literature. In general, triacylglycerides are not readily bioavailable and require digestive enzymes to break these complex lipids down into free fatty acid C15:0. Given that this product’s once-daily pill contained only 50 mg of triacylglyceride C15:0, this product is not expected to help most people achieve active circulating concentrations.

Question 3: Are there any oils in your product, and is there evidence of any lipid peroxidation? 

Peer-reviewed studies have demonstrated that pure free fatty acid C15:0 is particularly effective in strengthening cell membranes. This is due to its role as a stable odd-chain saturated fatty acid powder. The molecular structure of free fatty acid C15:0 has no double bonds, which makes it resistant to lipid peroxidation and rancidity (in the bottle and our bodies). 

In contrast, unsaturated fatty acids are unstable oils with double bonds that are susceptible to lipid peroxidation and rancidity. Polyunsaturated fatty acids have multiple double bonds and are even more likely to oxidize. Lipid peroxidation in our cell membranes is a primary driver of cellular and aging-related breakdown, as well as shortened longevity.

Lipid peroxidation can be measured in products using two tests: peroxidation value and p-anisidine. Peroxidation value is a direct measurement of oxidation, while p-anisidine is a measurement of lipid peroxidation products, including aldehydes.

Fatty15: Fatty15 contains only pure, free fatty acid C15:0 powder. When tested by an independent third party, fatty15 had no lipid peroxidation.*

Other product: The other product contains 13% C15:0 and 57% unsaturated fatty acid oils, including 11% polyunsaturated fatty acids. When tested by an independent third party, this product had measurable lipid peroxidation (peroxide value = 8.5 mg/kg of fat and p-anisidine value of 13). These oils counteract the cell-stabilizing effects of C15:0.* 

Question 4: Does your product use a scent tab?

Plastic scent tabs are used in oil-based supplements to help cover up unpleasant smells and taste that are caused by rancid oils. Pure free fatty acid C15:0 is a powder with no odors and no taste. As such, a pure C15:0 supplement has no need for scent tabs.

Fatty15: Fatty15 is a powder with no oils and no lipid peroxidation. No scent tabs needed.*

Other product: The other product contains a strong vanilla scent tab, which is consistent for supplements that need to mask bad odors and taste caused by lipid peroxidation.

Question 5: Are there any proinflammatory fats in your product?

Peer-reviewed studies have shown that pure free fatty acid C15:0 (aka fatty15) has anti-inflammatory activities, including lowering 18+ pro-inflammatory cytokines across 10 out of 12 primary human cell systems at 20 to 50 µM. This is due, in part, to C15:0’s role as a JAK/STAT inhibitor.

In contrast, C16:0, C18:0 and omega-6 fatty acids are well known to be proinflammatory. Further, omega-6 to omega-3 ratios greater than 1:1 are known to be proinflammatory. Omega-3 fatty acids induce proinflammatory JAK/STAT signaling.

Fatty15: Fatty15 contains > 98.5% pure free fatty acid C15:0 powder used in the above-mentioned studies.*

Other product: When tested by an independent third party, the other product contains 13% C15:0 and 25% pro-inflammatory fatty acids, including C16:0 (11%), C18:0 (2%), and omega-6 (11% ). This product had an omega-6 to omega-3 ratio of 25:1. These proinflammatory fatty acids counteract the antiinflammatory effects of C15:0.*

Question 6: Are there any peer-reviewed studies specifically on this product’s exact formulation - especially related to the claims being made?

Peer-reviewed studies demonstrating the active benefits of C15:0 have consistently used pure free fatty acid C15:0 powder. When C15:0 is combined with equal or greater levels of other fats, its efficacy - including metabolic benefits - is lost. As such, it is critical that any supplement containing equal or greater amounts of multiple fatty acid types - and claiming to have C15:0 benefits - have peer-reviewed studies using their specific formulation, to make any C15:0-related benefit claims.

Fatty15: Fatty15 contains the same > 98.5% pure free fatty acid C15:0 powder used in peer-reviewed studies demonstrating C15:0’s cellular health benefits.

Other product: Only 13% of this product is C15:0, while 87% are other types of fatty acids, including pro-inflammatory and pro-oxidative fatty acids. This product’s formulation has no peer-reviewed studies demonstrating its claimed benefits.*

Question 7: Where is your supplement made?

Many consumers want to know where supplements are made. 

Fatty15: Fatty15’s > 98.5% pure, free fatty acid C15:0 powder ingredient (FA15) is made in FDA-compliant pharmaceutical and food-grade cGMP European facilities.

Other product: This product contains multiple ingredients preceded by “PhytoSureTM” and “NutraAssureTM”, including their C15 ingredient. These ingredients and supplements are made by CAS BioSciences, which are manufactured in China. “CAS” stands for the Chinese Academy of Sciences, which is a national academy of the People's Republic of China.


Here at fatty15, your health is our top priority. That's why our team of nerdy doctors and scientists dedicated years (and years) to lead and publish peer-reviewed studies on our pure, free fatty acid C15:0 ingredient...before we brought fatty15 to the market. And why our science continues today.

In summary, the beauty and efficacy of C15:0 lies in its simplicity. Our award-winning, science-backed, patented and pure C15:0 ingredient in fatty15 (the only ingredient in fatty15) was tailor made to deliver a healthier you. 

*Data based on product testing of fatty acids and lipid peroxidation by independent 3rd party laboratory (Eurofins Food Chemistry Testing Madison)

Cited Literature

DiscoverC15.com (compilation of peer-reviewed literature on C15:0)

Reversing cellular aging with fatty15 (blog containing science and cited literature)

Venn-Watson et al. (2020) Scientific Reports, C15:0 as an essential fatty acid; cell-stabilizing and mitochondrial-repairing activities 

Fu et al. (2021) Food Nutr Res, C15:0 as an AMPK activator

To et al. (2022) Int J Mol Sci, C15:0 as an mTOR inhibitor

Venn-Watson et al. (2022) PLOS ONE, Anti-inflammatory activities of fatty15

Stallings et al. (2013) Int J Clin Pharm Therapeutics, Pharmacokinetics of free fatty acid C15:0

Fave et al. (2004) Cell Mol Bio, Managing fatty acid bioavailability

Hulbert et al. (2005) J Theor Biol, Importance of fatty acid composition of membranes for aging

To et al. (2020) Nutrients, C15:0 as a JAK/STAT inhibitor

Korbecki et al. (2019) Inflamm Res, C16:0 causes inflammatory response

Mu et al. (2014) Nutrition, Saturated fatty acids (C16:0 and C18:0) and systemic inflammation

Patterson et al. (2012) J Nutrition Metab, Health implications of higher dietary omega-6 PUFAs

Simopoulos (2002) Biomed Pharmaco, Importance of the ratio of omega-6/omega-3 

Yan et al. (2013) Eur J Immunol Polyunsaturated fatty acids activate JAK/STAT

Bishop et al. (2023) Nutrients Pure C15:0, not C15:0 with food, provides metabolic benefits
Profile photo for Eric Venn-Watson

Eric Venn-Watson M.D.

Eric is a physician, U.S. Navy veteran, and Co-founder and COO of Seraphina Therapeutics. Eric served over 25 years as a Navy and Marine Corps physician, working with the special forces community to improve their health and fitness. Seraphina Therapeutics is a health and wellness company dedicated to advancing global health through the discovery of essential fatty acids and micronutrient therapeutics.

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