Testing Positive for Alcohol Despite Sobriety?
The factors that can influence a hair alcohol (EtG) result when you have not been drinking.
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Stopping drinking is hard-won, and a positive hair alcohol result afterwards can feel like it undoes the work. It usually does not. There are several well-understood reasons an EtG result can stay positive after the drinking has stopped, and most of them are about timing rather than truth.
1. EtG left over from before you stopped
Ethyl glucuronide is a metabolite of alcohol, and hair holds a historical record rather than a current one. Hair grows at roughly 0.7 to 1.5 cm per month, so a sample taken a few months after your last drink can still be made up largely of hair that grew while you were drinking.
The test is not describing today. It is describing the period during which that hair was formed.
2. Slow growth and dormant hair
Hair grows in cycles. Some follicles are actively growing — the anagen phase — while others are resting in the telogen phase, where the hair stays in the scalp without growing before it eventually sheds.
EtG from earlier drinking stays locked in those dormant hairs. If your growth rate is slow, or a higher-than-usual proportion of your hair is resting, older hair carrying EtG is still there to be sampled long after you would expect it to have gone.
3. Products containing alcohol
Shampoos, conditioners, sprays and especially mouthwash can contain alcohol, and regular use can deposit trace EtG onto hair from the outside. Mouthwash is the common culprit, because the alcohol content is high and the exposure is daily.
If you are being tested for abstinence, check the ingredients of everything you use on your hair and in your mouth, and switch to alcohol-free versions well before a test.
4. Contamination from hats and headwear
Hats, caps and other head coverings worn during your drinking period can hold residues that transfer back onto clean hair over time. Replacing or thoroughly washing that headwear removes the problem.
5. Individual differences
Two people can stop drinking on the same day and get different results three months later. Three things drive that.
How much, and how recently. Heavier or more frequent consumption leaves more EtG in the hair, and it takes longer to grow out.
Growth rate. Faster-growing hair produces clean, EtG-free hair sooner, so the sample taken is more likely to be new hair.
The proportion of dormant hair. More telogen-phase hair means more old hair still in place, and a slower fall in measured EtG.
None of that is within your control, which is exactly why a result close to the threshold deserves interpretation rather than a straight reading.
What to do about it
If you are testing for abstinence and the result does not match your experience, the useful steps are practical ones: switch to alcohol-free hair and oral products, replace headwear from your drinking period, and where the timeline matters, ask about segmental analysis so a falling pattern across months can be seen rather than averaged away.
Where a result carries consequences — a court matter, a treatment program, an employment condition — have it reviewed by an independent forensic toxicologist who can address these factors specifically and put the assessment in writing. The SoHT interpretive bands are the starting point for that conversation, not the end of it.
A positive result in the early months of sobriety does not diminish what you have done. Often it means the hair being tested is older than the decision you made.
Book a hair alcohol test, or call (03) 9380 5434 to talk it through first.
