The basic parameter of the fatty acid (or triglyceride) is the carbon chain length. According to this length they are divided into:
- Short-chain fatty acids (SCFA – up to 6 carbons)
- Medium-chain fatty acids (MCFA – 6 to 12 carbons)
- Long-chain fatty acids (LCFA – 13 to 21 carbons)
- Very long chain fatty acids (VLCFA – 22 or more) – very few cases
Unsaturated fatty acid chains have a length of up to 24 carbons, some saturated even up to 37. Sometimes a different boundary is shown between LCFA and VLCFA (very long starting from 18 or 20), or the entire division is shifted.
Fatty acids (mostly of the same or similar length) are linked together creating triglycerides, namely:
- Short-chain triglycerides (SCT) – there are at least 2 SCFAs in the triglyceride
- Medium-chain triglycerides (MCT) – at least 2 MCFAs
- Long-chain triglycerides (LCT) – at least 2 LCFAs
- Very long chain triglycerides (VLCT) – at least 2 VLCFAs
The longer the carbon chain, the higher the melting temperature (the longer the fat remains solid when heated).