# Volatile sulfur compounds

> Volatile sulfur compounds (VSCs) are trace sulfur-containing aroma molecules, especially prenylated thiols, that give cannabis its skunky, gassy smell at concentrations far below terpenes.

- Canonical: https://genetixbay.com/knowledge/glossary/volatile-sulfur-compounds.html
- Also written: VSCs, VSC, VSCs (cannabis), sulfur volatiles, sulphur volatiles, volatile sulphur compounds, skunk compounds, thiols
- Glossary category: Cannabinoids and terpenes · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Volatile sulfur compounds are small aroma molecules containing [sulfur](https://genetixbay.com/knowledge/glossary/sulfur.md), such as thiols, sulfides and thioesters. Oswald et al. (2021, *ACS Omega*) used two-dimensional [gas chromatography](https://genetixbay.com/knowledge/glossary/gas-chromatography.md) with sulfur detection to identify a family of prenylated VSCs in cannabis. The most important, [3-methyl-2-butene-1-thiol](https://genetixbay.com/knowledge/glossary/prenylthiol.md) (prenylthiol), was the main driver of the "[skunk](https://genetixbay.com/knowledge/glossary/skunk.md)" aroma.

## In practice

VSCs occur at trace concentrations, far below the 1-3% w/w total of the [terpenes](https://genetixbay.com/knowledge/glossary/terpene.md), but human odour thresholds for thiols are extremely low, so tiny amounts dominate the smell. That explains why two flowers with near-identical [terpene panels](https://genetixbay.com/knowledge/glossary/terpene-test.md) can smell very different. The same group reported VSC levels rising late in flowering and into curing and falling during storage. A follow-up (Oswald et al. 2023) found that minor non-terpenoid compounds drive many distinctive "exotic" aromas.

## Don't confuse with

- **Terpenes**: the bulk aroma class, but not the source of skunk.
- **Sulfur nutrition**: feeding more sulfur has no demonstrated effect on VSC levels.

## Myth check

"Extra sulfur feeding makes buds skunkier" has no controlled evidence. See [sulfur](https://genetixbay.com/knowledge/nutrients/sulfur.md) and [Mythbusters](https://genetixbay.com/knowledge/mythbusters.md).

## Related terms

[Prenylthiol](https://genetixbay.com/knowledge/glossary/prenylthiol.md), [Terpene](https://genetixbay.com/knowledge/glossary/terpene.md), [Terpene profile](https://genetixbay.com/knowledge/glossary/terpene-profile.md), [Gas chromatography](https://genetixbay.com/knowledge/glossary/gas-chromatography.md)

## Read more

- [Why everything tastes the same: the evidence that commercial cannabis is converging](https://genetixbay.com/knowledge/genetics-history/why-everything-tastes-the-same.md)
- [Sulfur (S) in cannabis: role, deficiency, targets and sulfate sources](https://genetixbay.com/knowledge/nutrients/sulfur.md)

## Sources

1. Oswald IWH, Ojeda MA, Pobanz RJ, et al. 2021. Identification of a new family of prenylated volatile sulfur compounds in cannabis revealed by comprehensive two-dimensional gas chromatography. ACS Omega 6(47):31667-31676. https://doi.org/10.1021/acsomega.1c04196
2. Oswald IWH, Paryani TR, Sosa ME, et al. 2023. Minor, nonterpenoid volatile compounds drive the aroma differences of exotic cannabis. ACS Omega 8(42):39203-39216. https://doi.org/10.1021/acsomega.3c04496