Longevity Supplements: How C15 Stacks Up vs. Others
Published by Dr. Venn-Watson

Dr. Eric Venn-Watson’s Highlights
- Longevity supplements are those that target some of the 12 Hallmarks of Aging that occur in our cells. By targeting these hallmarks, we can effectively slow down cellular aging and extend our own longevity. Fatty15 is a pure C15:0 supplement that has been shown to target multiple hallmarks of aging and slow cellular aging.
We could attribute the boom in longevity supplement sales to famous biohackers, but truth be told, the human race has been hyper-focused on remaining “forever young” for decades. Our quest to stay alive longer has morphed into not only the ability to live longer, but also to stay healthy longer.
Increasing both our healthspan and lifespan is a primary focus of longevity researchers. Experts in the field of longevity have concluded that the biological aging process, that is, the way our bodies age, irrespective of our chronological birthdays, happens due to processes inside our cells.
A new focus has arisen in targeting these processes in order to slow aging and even allow us to age (biologically) in reverse.
What Is Biological Aging?
The 12 Hallmarks of Aging describe how changes in our cells and bodies cause us to age. When these processes happen with more frequency, the aging process accelerates. When they slow down, the aging process also slows.
The 12 hallmarks include:
- Decreased cellular communication. This refers to a decrease in cellular communication, which can lead to dysfunction and loss of homeostasis in the body.
- Genomic instability. Genomic instability refers to changes that happen to our DNA due to exposure to environmental toxins or illness.
- Telomere attrition. Telomeres on the ends of our chromosomes become shorter as DNA replicates. With each replication, the telomere gets shorter, and a portion of our DNA is lost.
- Epigenetic alterations. Alterations we make to our bodies through diet, exercise, and even pregnancy are considered epigenetic alterations.
- Loss of proteostasis. Loss of proteostasis refers to a malfunction in how our cells create and use proteins.
- Deregulated nutrient sensing. Cells need to sense and obtain nutrients to thrive. When they can no longer sense and collect the nutrients they need, deregulated nutrient sensing occurs.
- Mitochondrial dysfunction. Mitochondria produce energy (ATP) for the cells. Over time, they produce less ATP but more reactive oxygen species (ROS), which is toxic to cells.
- Cellular senescence. Some cells lose function but do not die, creating an inflammatory environment in the body. These cells are called senescent cells.
- Stem cell exhaustion. Stem cells can be used to repair any tissue in the body. Over time, our stem cells no longer function properly, leading to stem cell exhaustion.
- Disabled macroautophagy. Cells use an internal clean-up system called autophagy that helps them recycle old cell parts into new ones. Over time, this process also fails.
- Chronic inflammation. Chronic, low-level inflammation in the body leads to numerous metabolic problems and age-related illnesses.
- Dysbiosis. Our gut microbiome helps keep our body in balance. The gut microbiome also communicates with our body, and even the brain. When the gut microbiome significantly changes, it is said to be in a state of dysbiosis.
For a deep dive into each of the 12 hallmarks, you can check out this post. For now, we’ll consider the basics, and how each of the following supplements addresses the hallmarks of aging and how they compare with one another.
What Is Metformin?
Metformin was derived from a plant called Galega Officinalis (aka goat’s rue) in the early 1900s. It was initially used to treat urinary tract infections, but it was later discovered that it could lower blood sugar levels. In 1995, it was approved for use in the US for people with type 2 diabetes and is the most popular medication prescribed for people with unregulated blood sugar levels.
Common Uses
Metformin is a medication that has consistently been used to treat unregulated blood sugar levels in people with type 2 diabetes. In addition, it is used to help regulate blood sugar for prediabetics, people with gestational diabetes, and polycystic ovary syndrome (PCOS). It is sometimes used off-label to help with weight gain from anti-psychotic medications.
How it May Target Biological Aging
Metformin has recently been studied by longevity researchers to explore whether or not it might be an effective therapy for addressing the hallmarks of aging. Metformin helps with nutrient sensing due to its ability to improve insulin sensitivity.
It has also been shown to address immune response, aid in cellular repair and autophagy, activate AMPK (a molecule that helps with many cell processes), improve mitochondrial health, and reduce telomere attrition.
However, more studies are needed to conclude whether metformin would be an effective drug to specifically take for longevity purposes. In animal studies, metformin did not increase lifespan.
Concerns
Metformin has known to cause abdominal pain, gastrointestinal issues, fast breathing, fatigue, and muscle cramping.
What Is Rapamycin?
Rapamycin is an immunosuppressant drug that targets the body’s immune system. It works by blocking white blood cells from rushing to the scene of what could be considered a threat, like a new organ that has been transplanted into the body. It also blocks a particular protein that is associated with cell division.
Common Uses
It is commonly used by organ transplant recipients and bone marrow recipients. Rapamycin was not discovered until 1972.
It’s discovery on Easter Island led to research and development into its ability to block certain pathways in the body, and it was approved for use in kidney transplant recipients in 1999. Since that time, it has been approved for other uses. It is given to patients to stop the growth of tumors and aid in healing after angioplasty surgeries.
How it May Target Biological Aging
Rapamycin blocks white blood cell activity by inhibiting the mTOR (mammalian target of rapamycin) pathway. This specific pathway is also involved in nutrient sensing and cellular autophagy. For mTOR to work correctly, there needs to be a balance of our mTOR function.
Too much mTOR signaling can cause an environment of inflammation and negative health outcomes. In animal studies, a slight increase of mTOR activity was shown to reduce lifespan by up to 20%.
Concerns
Rapamycin has serious side effects, which can be painful and debilitating. Patients often report bone pain, headaches, muscle weakness, poor wound healing, burning sensations while urinating, nerve pain, dark stool and urine, loss of balance, chills, cough, confusion, nausea, vomiting, slurred speech, ulcers and bleeding gums, fatigue, and more. The list of commonly known side effects is lengthy.
What Is C15:0?
C15:0 is an odd-chain saturated fatty acid that is essential, which means we need it to thrive but can’t make it on our own. We have to get it from food or supplements. C15:0 is found in full-fat dairy products and some fish, but only in trace amounts.
C15:0 works by strengthening our cells, targeting the hallmarks of aging, and binding to receptors throughout the body that keep the body in homeostasis.
Common Uses
C15:0 is commonly used to support longevity. Dubbed “The Longevity Nutrient,” it was discovered by a team of scientists studying longevity in dolphins.
Dolphins that had a higher level of C15:0 in their bodies had fewer occurrences of age-related illness. Taking their research further, the scientists discovered that these benefits were available to humans with higher levels of C15:0, too.
How it Targets Biological Aging
C15:0 targets and helps slow biological aging in our cells and bodies by:
-
Strengthening cell membranes by up to 80%.
- Activating AMPK, which helps with nutrient sensing, removal of senescent cells, and triggers autophagy.
- Regulating inflammatory response and significantly calming and lowering proinflammatory cytokines, a key driver in aging.
- Restoring mitochondrial function. C15:0 improves ATP output (by up to 350%) and reduces ROS.
- Activating PPARɑ and PPARẟ receptors. By activating these receptors, C15:0 has been shown in peer-reviewed studies to support metabolic, immune, heart, and liver health in relevant models. These receptors also help to improve mood and deepen sleep.
- Improves the gut microbiome.
C15:0 also lowers “bad” LDL cholesterol and improves liver enzymes. C15:0 is a crucial nutrient that strengthens and protects cells against aging and improves metabolic, liver, red blood cell, and cognitive health.
Concerns
C15:0 is an essential nutrient and not having enough C15:0 can result in a recently recognized deficiency syndrome. This deficiency is known as Cellular Fragility Syndrome.
Nearly one in three people globally may have low levels of C15:0, resulting in Cellular Fragility Syndrome (CFS). CFS causes cells to become fragile and susceptible to premature breakdown. It is also linked to ferroptosis, a type of cell death that is known to accelerate aging and illnesses like type 2 diabetes and NAFLD.
Thankfully, fixing Cellular Fragility Syndrome can be easily accomplished by increasing your levels of C15:0 through food or supplementation.
Elevate your cells. Elevate your self.
Buy NowHow To Get C15:0
If you aren’t sure what your C15:0 levels are, you can ask your doctor to run a blood test, or you can click here for our at-home finger-prick test. This test will measure your levels of C15:0. Optimal levels are considered between 0.2% and 0.4% of your total fatty acid count.
Increasing your C15:0 levels is easy with fatty15, the first and only supplement that contains the pure, vegan-friendly, sustainably produced, award-winning, and patented version of C15:0 known as FA15™.
Why a Supplement May Be Better
There are a few reasons why it may be better to get your C15:0 from a supplement than from your food. C15:0 is found only in trace amounts in foods like whole milk and full-fat butter.
Consuming more whole milk or butter can be problematic because:
- It’s packed with excess calories and sugar from lactose.
- The C15:0 is packaged along with unhealthy, even-chain, saturated fats.
- Branches of triglycerides must be broken down to access the C15:0, making absorption less efficient.
- It involves cows and is not vegan-friendly.
Fatty15 gives you everything you need, nothing you don’t, already comes in free fatty acid form so it is ready to be absorbed, and never involves cows or calories. It’s an easy way to increase your C15:0 levels, prevent Cellular Fragility Syndrome, and improve your long-term metabolic, liver, immune, red blood cell and cognitive health.
Fatty for Life
Longevity supplements are becoming more popular, but understanding how they work and what side effects are involved is important in making wise decisions about our long-term health. Taking fatty15 each day is a science-backed and simple option to target the hallmarks of aging, help slow cellular aging, and improve our long-term health.
Sources:
Hallmarks of aging: An expanding universe | PubMed
Metformin: historical overview | PubMed
Is metformin a wonder drug? | Harvard Health
Definition of rapamycin | NCI Dictionary of Cancer Terms

Eric Venn-Watson M.D.
CEO, Co-Founder
Senior Scientist, Co-Founder
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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