Vegetable Glycerin (VG)
Skin cream, cough syrup — and acrolein when overheated.
⚠ Sounds harmless — it isn't
Glycerin klingt nach Kosmetik — und ist es auch. Beim Erhitzen über 280 °C zerfällt es jedoch zu Acrolein, einem starken Atemwegsreizstoff und IARC-2A-Karzinogen.
At a glance
- Also known as
- VG · Glycerin · Glycerol · Propan-1,2,3-triol
- CAS number
- 56-81-5
- Toxicity
Low
- Carcinogenic
- Not classified for cancer
- In cigarette smoke
- In vape aerosol
- Hauptkomponente, typisch 30-70 % des Liquids; pro Zug 1-3 mg
What is Vegetable Glycerin (VG)?
Vegetable glycerin (VG, glycerol) is a colourless, odourless, sweet, highly viscous liquid. Approved in the EU as food additive E422, the WHO classifies it as ADI „not specified“ (fundamentally safe), and it's a standard carrier in cough syrups, skin creams and glycerin soaps. In e-cigarette liquids, VG produces the dense, visible vapour clouds.
Why is Vegetable Glycerin (VG) in cigarettes?
While PG is responsible for the throat hit, VG in vape liquids provides vapour density and a sweet flavour note. Each puff delivers 1 to 3 milligrams of VG as aerosol into the lung. As with PG, oral and dermal intake has been studied for decades and is considered safe — long-term inhalation as aerosol by vapers has not.
What Vegetable Glycerin (VG) does to your body — short term
VG irritates mucous membranes less than PG, but at high doses can cause a dry throat and occasional coughing during inhalation. The viscous, sweet substance leaves a slight film on oral mucosa. In clinical studies on asthmatics, transient bronchoconstriction was measured immediately after VG aerosol inhalation — a sign that even the „harmless carrier“ acts on the airways short-term.
What Vegetable Glycerin (VG) does long term
VG's critical effect arises not during normal vaporisation, but during thermal decomposition: when heated above 270 °C — as at high wattages or in „dry hits“ — it breaks down to acrolein, a strong airway irritant and, since 2021, an IARC Group 2A carcinogen (source: Sleiman et al., ES&T 2016). In rarer cases, chronic VG aerosol users have also shown lipoid pneumonic findings — lung tissue infiltrated with fine glycerin droplets triggering inflammatory reactions.
Where else do you know Vegetable Glycerin (VG) from?
You know VG from cough syrups and skin creams, as a sweetener and humectant in food (E422), in glycerin soap (especially mild to skin), and in toothpaste. Industrially, glycerin is a raw material for explosives manufacturing (nitroglycerin) — the substance itself is widely used; its inhalation as an aerosol, though, is new.
How it compares
The workplace exposure limit for glycerin mist is 10 mg/m³ (OSHA PEL and ACGIH TLV-TWA); the German DFG MAK list doesn't separately list glycerin mist. A vaper with 300 puffs per day takes in roughly 0.5 to 1 gram of VG — not a problem in terms of pure VG toxicity, but the limit was set for industrial glycerin mist, not for the high vaporisation temperatures of a vape coil.
Workplace exposure limit: 10 mg/m³ (Glycerin-Nebel, OSHA PEL / ACGIH TLV-TWA)
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