C8 (caprylic acid) and C10 (capric acid) are the two medium-chain fats most MCT oils are built around, and the label ratio between them decides how fast the oil converts to ketones.
Two bottles can both say “MCT oil” and behave nothing alike. One is nearly pure caprylic acid; the other is a C8 and C10 blend with a little lauric acid folded in. The difference sits in the fatty-acid chain length, and that length governs how the body digests, absorbs, and burns each fraction.
Here’s what each fraction actually is, how they differ, and how to read a label so you buy the ratio you meant to buy.
What Do C8 and C10 Actually Mean?
C8 and C10 are shorthand for fatty-acid chain length: caprylic acid carries eight carbon atoms and capric acid carries ten. Anything labeled “MCT” means medium-chain triglyceride, a fat built on a chain in that middle range rather than a long one.
The numbers matter because chain length drives how the fat is processed. Shorter chains pass through digestion with less work, which is why C8 gets the attention it does.
- C8:0 — caprylic acid, also written octanoic acid. Eight carbons.
- C10:0 — capric acid, also written decanoic acid. Ten carbons.
- C6 and C12 — some coconut-derived oils also carry hexanoic acid and lauric acid, the twelve-carbon fat that behaves more like a long-chain fat.
Sports Research, for instance, lists its full-spectrum bottle as a C8, C10, and lauric acid blend, while its Keto C8 product is positioned as caprylic-acid MCT. Same brand, two different formulas — which is the whole point.
How Does C8 Compare to C10?
C8 is the faster-converting fraction and the one marketed hardest for ketone production; C10 is absorbed quickly too but is generally treated as less ketogenic. That distinction is the reason C8-only oils cost more per fluid ounce than blends.
Neither fraction is a medical treatment. Product pages describe MCTs as potentially fueling the brain and body, particularly on a ketogenic or low-carbohydrate diet, and that is a claim worth reading as marketing until product-specific clinical evidence backs it.
What Should You Check Before Buying?
Check the actual gram or percentage breakdown of each fatty acid, not the front label — “MCT oil” describes a category, not a fixed formula. Every manufacturer sets its own ratio, so comparing two bottles by price alone tells you almost nothing.
| Label Detail | What It Tells You | Watch For |
|---|---|---|
| C8 gram amount | How much caprylic acid per serving | Listed in grams, not just a percentage |
| C10 gram amount | How much capric acid per serving | Often the larger fraction in blends |
| C12 (lauric acid) | Full-spectrum vs. purified formula | Behaves more like a long-chain fat |
| Oil vs. powder vs. softgel | Serving size and dosing differ by form | Powder servings are scoops, not spoons |
| Smoke point | Whether it survives heat | Below 320°F — not a frying oil |
| Allergen line | Coconut is a tree-nut allergen | Stated on coconut-derived products |
| Container material | Reactivity with certain plastics | Use metal, glass, ceramic, HDPE/PET |
Dosing is the other mismatch. One product’s serving size never transfers to another — powders and softgels in particular.
If you want the ratio already sorted for you, this roundup of tested MCT oil with C8 and C10 compares the options side by side. Whichever bottle you land on, go slow: excess intake can cause digestive upset, and gradual introduction is the standard way to avoid it.
One more reference point before you settle: the Sports Research MCT oil product page publishes a full fatty-acid breakdown and use directions, which makes it a useful template for what a complete label actually looks like.
Common Questions
Is C8 or C10 better for ketone production?
C8 is generally considered the stronger ketone producer of the two, which is why C8-only oils command higher prices. C10 is still absorbed rapidly but is typically regarded as less ketogenic. If ketone output is your priority, a higher-C8 ratio fits better; if cost per ounce matters more, a C8+C10 blend is the practical choice.
Can you cook with MCT oil?
Not for frying. Sports Research lists its MCT oil’s smoke point below 320°F, so high-heat cooking degrades it. It works well stirred into coffee, tea, shakes, smoothies, salads, or marinades — applications where the oil is added rather than used as a cooking medium.
Why does MCT oil upset some people’s stomachs?
Excess intake can cause gastrointestinal discomfort, which is why both Sports Research listings advise starting small and increasing gradually. Beginning at a teaspoon and building toward a tablespoon over days or weeks is the usual approach. Anyone pregnant, nursing, managing a diagnosed condition, or taking prescription medicines should consult a healthcare professional first.
Sources
- Sports Research. “Premium MCT Oil, 32 oz” Supplies the C8/C10 gram breakdown, dosing guidance, smoke point below 320°F, plastic-reactivity warning, and coconut allergen statement.