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Fatty15 Reviews

We investigate if this new fatty acid can improve your mood and energy while reversing cellular damage.

Last Updated: Dec 28, 2022
Fatty15 Reviews

Diet trends are constantly changing. The role of fats in our diet is one of the most complicated and contentious topics, and the conversation about whether we should or shouldn’t include them seems to flip sides all the time. (Egg yolks, which were eschewed for a long time, provide most of the nutritional benefits of eggs, for example.) As we learn more about the intricacies of the human body, this advice will continue to shift.

In an exciting turn of events, a team of Navy researchers learned that a kind of saturated fat — what we’ve long been told is a “bad” fat — called pentadecanoic acid (or C15:0) may actually be essential for our health. They decided it was necessary to bring C15:0 into the limelight and created fatty15, the first (and, so far, only) C15:0 supplement on the market. We researched and tested fatty15 to find out whether or not these little capsules can make a big difference in your health.

Review Summary


  • Designed by the researchers who discovered C15:0’s benefits
  • No smells or side effects
  • Small capsule still provides big benefits
  • Naturally vegan
  • Ecologically conscious manufacturing and packaging
  • Made in cGMP-compliant facilities with third-party testing
  • Free shipping on all supplements


  • On the expensive side
  • Novelty means there are not many unbiased studies to confirm benefits

Bottom line

Fatty15 is a new kind of supplement for a previously overlooked fatty acid, designed by the experts who discovered its practical uses. Our testers experienced improvements in chronic inflammation and sleep quality within a few days, and full effects on mood stability, relaxation, and energy come within three months. It’s an expensive addition to a supplement routine, but the cutting edge is rarely inexpensive. And fatty15 is just as dedicated to sustainability as they are to your health. There’s still a lot of research to be done (particularly considering fatty15’s founders conducted most of the published studies), so time will tell as to whether or not fatty15 really works. That said, we think it holds a lot of promise and found it effective.

Our Top Picks


Fatty15 is an expertly designed fatty acid supplement made to improve chronic inflammation, sleep quality, mood, and energy.

Fatty15 is made and distributed by the very scientists who discovered its practical uses. It’s vegan, third party tested, and made in cGMP-compliant facilities. Enoy free shipping on all purchases.

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Why you should trust us

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

We extensively test each health service or product we review. We try our best to give you, our readers, an unbiased exploration of at-home health options, free of marketing jargon or gimmicks. We evaluate products and services based on their adherence to quality, the latest medical evidence and health standards, and a simple question: would we buy the product or service ourselves if it weren’t part of our job, and would we recommend it to family and friends?

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy.

What is fatty15?

Fatty15 is a pentadecanoic acid (C15:0) supplement designed by husband-and-wife team Drs. Stephanie and Eric Venn-Watson. Dr. Eric Venn-Watson worked for 20 years as a physician in the Navy, and Dr. Stephanie Venn-Watson is a veterinary epidemiologist with many scholarly articles, patents, and awards, among other achievements.

While studying dolphin health, they noticed that dolphins who ate more fatty fish lived longer and were generally healthier. They expected that dietary omega-3 content would be the defining factor, as older, healthier dolphins ate more fatty fish. However, the difference wasn’t in omega-3 but rather the amount of C15:0 in their diet. Considering we share many biological and cellular mechanisms with dolphins, they began studying if C15:0 could impact human health in the same ways and published their findings in a major scientific journal in 2020. Fatty15 was created soon after.

Each fatty15 capsule contains 100mg of C15:0 made from a vegan source at a cGMP-compliant facility. They’re extensively tested in-house and by an independent third party for purity and potency. You’ll get the best results if you take one fatty15 capsule daily with food.

Fatty15 is generally considered safe (GRAS) by federal organizations and appears safe for everyone except for children under four. It’s safe for pregnant and lactating parents, which isn’t typical for supplements. The only known side effect is a decreased appetite, which some people may use to help curb excessive snacking.

What is C15:0?

C15:0 is a fatty acid found in milk fat, particularly butter. Saturated fats have long been considered the “worse” kind of fat compared to unsaturated fats, which include the only other essential fatty acids (omega-3 and omega-6). However, recent discoveries around C15:0 have shaken this idea.

Though we’ve known it exists since the 1940s, most research around C15:0 has taken place in the last decade. Recently, we’ve learned that C15:0 is a partial peroxisome proliferator-activated receptor (PPAR) agonist. It’s thought to activate these receptors, which help the body regulate metabolism, inflammation, and cell proliferation.

The first studies investigating C15:0’s effects on human health were published around 2014, with one study pointing out the association between type 2 diabetes and blood C15:0 levels. Another study, a year later, discovered that higher levels of odd-chain fatty acids like C15:0 are associated with a lower risk of heart disease.

In 2020, Dr. Venn-Watson and two other scientists published a study in the prestigious journal Scientific Reports investigating C15:0’s potential role in human health after finding it helped dolphins age more gracefully. This paper directly suggests that C15:0 plays a role in stemming:

  • Inflammation
  • Anemia
  • High cholesterol
  • Fibrosis (hardening or scarring of tissues)

Most notably, this study proposed that C15:0 is an essential fatty acid that might bind to metabolic regulators and repair mitochondrial function. Mitochondrial functioning is an important clue into C15:0’s role in the human body since the mitochondria control all of our cellular energy as the powerhouses of the cell. At the same time, another study found that C15:0 had an anti-cancer effect against a particularly aggressive form of breast cancer.

Endocannabinoids and C15:0

Most recently – in August 2022, the month before this article was first published — Dr. Venn-Watson discovered that one metabolite of C15:0 is an endocannabinoid. Endocannabinoids are chemicals naturally created in the brain that have the same impact as cannabinoids like CBD and THC. Pentadecanoylcarnitine, the cannabinoid that comes from C15:0, worked as an anti-inflammatory agent across five different systems:

  • Cardiovascular
  • Immune
  • Neoplastic (abnormal tissue growths and tumors)
  • Pulmonary
  • Skin

It also acted on two types of serotonin receptors directly related to mood and anxiety, as well as both kinds of histamine receptors. This novel finding is exciting, indicating why C15:0 might substantially impact our emotional state and sleep patterns. Considering 70 million Americans report having sleep problems and 21 million experience clinical depression, this has the potential to be a game-changer.

However, you should take all of this information with a grain of salt. C15:0 is a new area of study requiring much more research from many different medical experts before we can firmly state that these facts are accurate and represent the typical experience.

Fatty15 vs. omega-3s

Despite both being fatty acids, there are many differences between C15:0 and omega-3s. Omega-3 fatty acids, found in fatty fish, krill, algae, and a few other aquatic sources, are unsaturated fats. A quick way to know if a fat is saturated or unsaturated is its state at room temperature: saturated fat will be solid (like butter), whereas unsaturated fat will be liquid (like olive oil). Omega-3s are one of two confirmed essential fatty acids, alongside omega-6, and are known to help:

  • Cardiovascular disease
  • Inflammation
  • High triglycerides
  • Blood pressure and coagulation
  • Arthritis and joint pain
  • Neurodegenerative disease
  • Fetal development

You can learn more about omega-3s in our guide to the best omega-3 supplements.

C15:0 is a saturated fat commonly found in butter and other dairy fats. This kind of fat doesn’t have the same benefits as unsaturated fats like omega fatty acids. The American Heart Association recommends limiting your saturated fats to no more than 7% of your total daily calories.

A study by Dr. Stephanie Venn-Watson and her colleagues in May 2022 compared the clinical effects of omega-3 and C15:0. Specifically, they tested four different strengths of eicosapentaenoic acid (EPA) and C15:0, as most research suggests that EPA is the driving force behind omega-3’s most prominent health benefits. The study found that C15:0 was able to accomplish everything that EPA did and more, affecting 28 additional cellular systems. (This is where fatty15 pulls the claim that it’s three times better than omega-3.) When tested against different simulated diseases, C15:0 worked as well as:

  • Antidepressant bupropion (Wellbutrin) on depressive symptoms
  • Antifungal and antibiotic medications climbazole and clarithromycin on infections
  • Chemotherapy medications gemcitabine and paclitaxel on cancerous tumors

EPA did not have these same effects and was actually toxic to some cells at the highest concentration. Of course, this was a general study and was the first of its kind, but it points to C15:0’s widespread possibilities in improving our health.

Fatty15 and omega-3 target different mechanisms to improve our metabolic, cardiovascular, and immune health, so you can take both as supplements simultaneously. However, fatty15 also has no taste or smell (unlike some fish-based omega-3 supplements) and is significantly less likely to cause GI problems while you’re getting started.

Products, pricing, and payments

Fatty15 is this brand’s only supplement, so getting started is easy. There is only one dose available (100mg), but you can order fatty15 in three different configurations:

There are very few material differences between these options. In all of them, you’ll get a glass bottle to hold all of your fatty15 capsules and either one or three paper packets, each holding 30 days’ worth of fatty15 (30 capsules). If you join a subscription service, you’ll receive refills every 30 or 90 days to keep your jar full.

Each starter kit contains:

  • A postcard with a printed thank-you note from co-founders Drs. Eric and Stephanie Venn-Watson
  • A larger postcard with fatty15’s benefits printed on the front and back
  • A newspaper-style magazine (referred to as an “educational insert”) illuminating customer reviews and rehashing fatty15’s benefits
  • A refillable glass jar
  • One or three packets of 30 fatty15 capsules, depending on the plan you’ve ordered

Insider Tip: Open the package but only see a glass bottle? Don’t worry — the capsules are in paper packets underneath the cardboard holding the bottle.

You can pay for your subscription with any major credit or debit card, PayPal, Shop Pay, or Google Pay.

Fatty15 also offers a straightforward referral program. If a new customer signs up for a subscription using your referral code, you’ll get a $20 discount off your next refill (and they’ll get 20% off their first subscription). Referral rewards never expire, and there’s no limit to how many people can use one referral code.

Shipping and returns

Shipping is free for all fatty15 pills, subscriptions, and refills, and merchandise ships at a flat rate of $4.95. At this time, you can only buy fatty15 within the United States. Subscription refills arrive several days before you run out of capsules, but if you forget to take them (or lose a bottle), it’s easy to move your ship date up or push it out.

Fatty15 has a 100% satisfaction guarantee for the first 30 days of your first order. If you start fatty15 and don’t like it for any reason, reach out to customer service to get your refund rolling. Beyond the first month, you can cancel your subscription at any time without penalty.

Insider Tip: Don’t pour every packet into the glass bottle on day one if you’re trying a 90-day subscription for the first time. You can get a full refund on unopened fatty15 packets if you don’t like them, even after the 100% money-back guarantee expires.

Other products

Fatty15 sells a few pieces of merchandise so that you can support them or flaunt your love for the supplement with branded clothing or accessories. These include:

  • Tote bag: $60
  • Drawstring hoodie in navy blue or black: $49.95
  • “Treat Yo Cells” design T-shirt in light green, navy blue, and gray: $19.95
  • “Ask me about mitochondria” design T-shirt in light green, navy blue, and gray: $19.95
  • White metal water bottle: $25

You can purchase a gift card for fatty15, which gives a 90-day supply to anyone you’d like for the full price of a 90-day starter kit without a subscription ($149.95). At this time, that’s the only gift card option they offer, but we hope to see them expand this option so people can gift smaller quantities of fatty15 to friends and family. There are no shipping, processing, or other fees associated with buying a gift card.

If you break or lose the glass bottle that fatty15 includes with every order, you can also order a new one for $10.

Our experience with fatty15

When our testing team ordered fatty15, the package arrived across the country five days after we placed an order. They took one supplement daily with breakfast for maximum absorption and began noticing a difference in days. One tester with an autoimmune disorder that causes chronic inflammation reported significantly less pain by day four. We also received reports of higher-quality sleep at the end of week two; they weren’t sleeping more but felt better rested and had more energy during the day.

Fatty15 takes up to three months for full effects, so while our testers didn’t feel everything promised during the few weeks they sampled it, they felt enough to say that fatty15 appears to work as suggested. Likewise, many of fatty15’s effects happen on a cellular level that is difficult to measure from a qualitative standpoint. However, at least one tester plans to add fatty15 to their personal regimen after the end of the testing period.

How we evaluate products

At Innerbody Research, we customize our evaluation criteria depending on the type and nature of the health-related service or product. But in general for health products and services, we have five broad areas that we explore in our evaluations, including:

Quality: How well does the company deliver its core service(s) to the customer? How is advanced technology used for accuracy and safety? What evidence of efficacy does the company provide? Are manufacturing standards high quality?

User-friendly: How intuitive and convenient is the service or product? To what degree is the company interface helpful and understandable?

Value: Are you getting your money’s worth? Are there any hidden costs or charges? Does the company offer discounts?

Privacy: If health data is stored, will your data be stored securely? Are payments secure? Does a company market your information?

Customer support: With personalized products and services, how well does the company address your individual needs? If a product or service turns out not to work for you, are there satisfaction guarantees or return policies that protect you?

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