MCT Oil Is Three Different Products: C8 vs C10 vs Blends and the Chain-Length Math the Label Hides

Walk into any supplement aisle and pick up two bottles labeled "MCT oil." Read the front of both. They look identical. One is $18 for 32 ounces. The other is $42 for 16 ounces. The clerk shrugs and says they are the same thing, just different brands.

They are not the same thing. They are, in the most technical sense, not even the same product category. MCT — medium-chain triglyceride — is not a molecule. It is a size class. The class contains at least four distinct fatty acids that differ from each other in absorption pathway, ketone-generation potential, GI tolerance, price, and food-industry supply chain by an order of magnitude. A "pure MCT oil" that leans on the cheap end of the chain-length spectrum is closer in behavior to melted coconut oil than to the caprylic-acid product it sits next to on the shelf, but nothing on the front of the bottle tells you which one you bought.

This post is the chain-length breakdown for MCT: what C6, C8, C10, and C12 actually are; how the absorption pathway differs by chain length; what the ketone-generation numbers look like for each; the GI-tolerance math that decides whether 15 grams is a tolerable dose or a bathroom emergency; the four label patterns you will see and what each one is hiding; and the 20-second Supplement-Facts label read that tells you which of the three products you are actually holding.

What a medium-chain triglyceride is

A triglyceride is a glycerol backbone with three fatty acids esterified to it. Fatty acids are categorized by carbon-chain length: short-chain (fewer than 6 carbons), medium-chain (6 to 12 carbons), long-chain (14 carbons or more). "MCT oil" is a product made by hydrolyzing a source oil — historically coconut, sometimes palm kernel — separating the medium-chain fraction, and re-esterifying those fatty acids onto a glycerol backbone. The result is a clear, odorless oil at room temperature.

The medium-chain family, in order of carbon count:

• C6 — caproic acid. Six carbons. Rarely present in commercial MCT oil in meaningful amounts because it is unpleasant in the mouth, sharply GI-irritating, and smells like a barnyard. Purified MCT products typically remove it.
• C8 — caprylic acid. Eight carbons. The fastest-absorbed, most ketogenic fraction. This is the fatty acid the "MCT for ketosis" and "MCT for cognitive performance" products are built around.
• C10 — capric acid. Ten carbons. Second-fastest, second-most ketogenic, cheaper to produce than C8 in isolation. Common in "C8/C10 blends."
• C12 — lauric acid. Twelve carbons. Behaviorally closer to a long-chain fatty acid than to a true MCT — it is absorbed through the lymphatic system rather than through the portal vein, produces minimal ketones, and does not deliver the "MCT effect" the marketing sells.

The chain-length composition of the finished MCT product is a function of the source oil and how aggressively the manufacturer fractionated it. Coconut oil is roughly 6-9% C8, 5-8% C10, and 45-50% C12 — the majority of coconut oil, by fatty-acid mass, is lauric acid. A cheap "MCT oil" made by minimally fractionating coconut oil to remove the long-chain species will still be C12-dominant. A premium C8-only product requires a much more aggressive fractionation and costs roughly 3 to 5 times more per gram.

The question that matters at the point of purchase is: what is the C8, C10, and C12 breakdown of the product in my hand, and does the label tell me?

The absorption pathway differences that make chain length matter

Long-chain fatty acids (C14 and up) are absorbed from the intestine, packaged into chylomicrons in the enterocyte, dumped into the lymphatic system, and delivered to the systemic circulation via the thoracic duct. This is a slow, energy-intensive process. The fat has to be emulsified with bile, digested by pancreatic lipase, absorbed, re-esterified, packaged, transported — the whole pathway takes hours and delivers the fat first to peripheral tissues, not to the liver.

C8 and C10 do not run that pathway. They are short enough to be absorbed directly across the enterocyte, into the portal vein, straight to the liver. No chylomicron packaging. No lymphatic detour. Absorption is measurable in the plasma within 30 minutes. Once in the hepatocyte, they enter the mitochondrion without needing the carnitine palmitoyltransferase shuttle that long-chain fatty acids depend on, and they undergo beta-oxidation rapidly, producing acetyl-CoA, which flows into ketogenesis when the fed state is not blocking it. The result: a measurable rise in blood ketones (beta-hydroxybutyrate) 30 to 90 minutes after ingestion.

C12 is the awkward middle case. Approximately 25 to 30 percent of ingested C12 takes the portal-vein pathway; the rest goes through the lymphatic chylomicron pathway. The ketogenic response to a C12-heavy product is roughly one-third to one-half that of a C8-only product at the same total mass. Coconut oil, which is C12-dominant, produces a small ketone bump; a C8-only MCT product at the same dose produces a large one.

Chain length also drives the GI-tolerance story. The rapid osmotic and absorptive load of a large C8 dose in an unadapted GI tract commonly causes cramping, urgency, and diarrhea. C10 has a milder profile. C12, because a chunk of it takes the slower lymphatic pathway, is the most GI-tolerable. This is the actual mechanism behind the widely-cited "start with 5 grams, work up" guidance — the recommendation was written by people using C8/C10 blends or C8-forward products, not people using coconut oil.

The ketone-generation numbers

Studies comparing equivalent gram-for-gram doses of different chain-length fractions in fasted or fed subjects consistently show:

• C8 alone produces the largest ketone response. A 20-gram dose of pure C8 in a fasted subject can raise beta-hydroxybutyrate to 0.4 to 0.7 mmol/L over baseline within 90 minutes.
• C10 alone produces roughly 60 to 75 percent of the C8 ketone response at equivalent doses.
• A 60/40 C8/C10 blend produces roughly 80 to 90 percent of the pure-C8 response — most of the ketogenic effect, at a lower price point per gram.
• C12 alone (or coconut oil) produces 20 to 35 percent of the pure-C8 response.
• Long-chain fatty acids (e.g., olive oil control) produce essentially no acute ketone rise.

These numbers matter for the buyer who is choosing MCT for a specific purpose. The "cognitive performance in a fasted state" use case — the one that drove the popularity of MCT in the biohacker and ketogenic-diet communities — is a C8 story. The "add fat to my coffee for satiety" use case is a broader story where any of the products will deliver some satiety and thermogenic effect. The "I read that MCT is healthy" use case is not a specific enough claim to match to a fatty acid.

If you are paying a premium price for an MCT product, the question is whether the ketone response you are chasing justifies the premium. If you do not need the ketone response — you are not fasted, you are not on a ketogenic diet, you are not chasing the acute cognitive-performance effect the C8 literature describes — you may be paying triple for a product that is not delivering triple the effect for your goal.

The GI-tolerance math

Almost every negative MCT experience comes from a dose above the person's individual tolerance threshold, taken on an empty stomach, in a chain length they were not adapted to. The tolerance ceiling is not "20 grams" or any other fixed number — it is the interaction of dose, chain length, meal context, and adaptation state.

Working rules from the literature and from a decade of practice:

• First-ever dose of a C8-forward product: 5 grams (roughly one teaspoon), with food, once per day for 3 to 5 days. Wait for GI adaptation.
• Escalation: add 5 grams every 3 to 5 days, tolerating each step before escalating again, up to a personal ceiling that is typically 15 to 25 grams per single dose in adapted users.
• Empty-stomach dosing cuts the tolerance ceiling roughly in half. If a 20-gram dose is tolerable with a meal, expect 10 to 12 grams to be the empty-stomach ceiling.
• Splitting the dose across two or three intake events per day extends the total daily tolerance. A user who cannot take 25 grams at once may tolerate 15 g + 10 g in split servings.
• A C12-dominant product ("coconut MCT") is more GI-tolerable at higher single doses but delivers less of the ketogenic and cognitive effect per gram. Choose it for a fat-source use case, not a ketone-target use case.

The most common failure mode is a first-time user reading a testimonial that mentions "30 grams before a morning workout," taking that dose on an empty stomach with a C8-forward product they have not used before, and spending the next four hours regretting it. The failure is a dosing failure, not a product failure. Written into the label of any MCT product should be the escalation protocol; almost no product prints one.

The four label patterns

The composition of an MCT product is not always transparent on the label. The four patterns you will see, ranked from most honest to most misleading:

Pattern 1 — Fully specified chain-length composition. The label states, per serving, the C8 and C10 mass and (if present) the C12 mass. Example: "Caprylic acid (C8) 12 g, Capric acid (C10) 3 g" on a 15 g serving. This is the honest format. You know exactly what you bought. Products at this level of transparency typically also state the source (e.g., "from sustainably sourced coconut") and the extraction method (fractionation, esterification method). Expect a price premium.

Pattern 2 — Ratio labeling without per-gram mass. The label states "C8/C10 60:40 blend" or "premium 70:30 C8:C10" but does not break out the actual mass per serving of each fraction. This is acceptable — the ratio plus the total-serving-fat mass lets you back out the numbers — but be alert to the missing C12 disclosure. A "C8/C10 blend" that also contains 20 percent C12 as an undisclosed filler is a real label practice.

Pattern 3 — "MCT Oil" with no composition disclosure. The label states "MCT Oil 14 g" per serving and offers no chain-length breakdown at all. This is the mid-range product. It is almost certainly a C8/C10/C12 blend, often heavier on C12 than the buyer expects, because C12 is cheaper. The ketone response will be lower than a C8-forward product per gram. Buy it as a fat source, not as a ketone-target product.

Pattern 4 — "MCT Oil" that is fractionated coconut oil with no further specification. The ingredient list reads "MCT oil (from coconut)." The bottle is cheap. The product is nearly indistinguishable from a lightly fractionated coconut oil — the long-chain fraction has been removed but the C12 has been left in. Nutritionally this is closer to coconut oil than to the products marketed for ketogenic use. It works for a satiety, cooking-fat, or "MCT-adjacent" application. It does not work as a ketone-target product.

The rule: if the label does not tell you the C8 and C10 numbers, assume you are looking at pattern 3 or pattern 4 and price accordingly. A product asking pattern-1 prices for pattern-3 disclosure is failing the buyer.

The 20-second Supplement-Facts label read

At the shelf:

1. Turn the bottle to the Supplement Facts panel. Ignore the front-of-label claims.
2. Look for a chain-length breakdown under "MCT" or "Medium chain triglycerides." If C8 (caprylic acid) and C10 (capric acid) each have a stated mass per serving, you have a pattern-1 product. Buy accordingly — if you want ketone response, look for at least 8 to 12 grams of C8 per serving.
3. If only a ratio is stated ("C8:C10 70:30"), multiply the total MCT mass by the ratio to derive the C8 and C10 grams. Check for a C12 disclosure elsewhere on the label; its absence does not guarantee its absence in the product.
4. If the label says only "MCT Oil" with no breakdown, look at the ingredient list. "MCT oil (from coconut oil)" with no further specification is pattern 3 or 4. Do not pay pattern-1 prices for it.
5. Check the source oil. Coconut is standard. Palm kernel is chemically similar but carries a supply-chain and sustainability question. Any source described as "vegetable oil" without further specification is a red flag.
6. Check the serving size. Some products list a 15-gram serving that no unadapted user could tolerate; the escalation ladder is on you, not on the label.

Where Scythene fits

Scythene's supplement line is being built on the same transparency principle you should apply at the shelf: every fatty acid gets its own mass line on the label, no blend ratios that hide a C12 filler, and the escalation protocol lives on the label itself so the first-time user knows the dose is not "one serving as directed." The MCT category is one of the cleanest illustrations of why chain-length transparency matters — and why "MCT oil" without a breakdown is doing the buyer a disservice, whether the buyer notices it or not.

Read the label. Ask for the numbers. Do not pay pure-C8 prices for lightly-fractionated coconut oil.