Expired CBD? Reading the best-before date on flower, hash and oil

Two statements coexist on food packaging, and the administration draws a clear line between them. The date limite de consommation is written "� consommer jusqu'au" ("use by"): the public service defines it as the date after which consumption becomes dangerous to health. It covers highly perishable foods and sale is forbidden once it has passed. Regulation (EU) No 1169/2011 sets its regime at article 24.

The date de durabilité minimale is written "� consommer de préférence avant le" or "avant fin" ("best before" or "best before end"). Going past it signals a drop in taste or nutritional quality, with no health danger. Some foods are even exempt from it: fresh fruit and vegetables, wines, vinegars, salt, lump sugar, chewing gum.

The code de la consommation (the French consumer code) has added a useful refinement. Its article L412-7, created by the anti-waste law of 10 February 2020, allows the DDM to be accompanied by wording recalling that "the product remains fit for consumption after this date". Décret n° 2022-1440 du 17 novembre 2022 settled the exact form: "Pour une dégustation optimale," ("for the best tasting experience") in front of the date, "Ce produit peut être consommé après cette date" ("this product may be consumed after this date") beside it, or both.

None of the above applies mechanically to a flower or a resin sold in France: these products are not foodstuffs, they are not intended for ingestion and they are restricted to adults. The arrêté du 30 décembre 2021 (the French ministerial order on hemp) governs the sector. Only Cannabis sativa L. varieties listed in the official catalogues, whose delta-9-THC content does not exceed 0.30%, may be grown, imported or used, and the same threshold applies to extracts. The date printed on a pouch therefore commits the batch's keeping quality, not food safety.

Cosmetics, on the other hand, are squarely governed. Regulation (EC) No 1223/2009 requires, at its article 19, that the date up to which the product, kept in appropriate conditions, continues to fulfil its initial function be stated: that is the cosmetic DDM, preceded by the symbol in annex VII or by the words "best before end". Beyond thirty months of durability, that DDM is no longer required and the label carries the period after opening, under the open jar pictogram. A hemp massage oil falls within that framework; the CBD oils in the catalogue come under different labelling.

On the dried form, the only public normative reference concerns water. Standard ASTM D8197-22 specifies for dried cannabis flower a water activity between 0.55 and 0.65: above, to rule out the development of micro-organisms, moulds included; below, to avoid breakage when handled.

The rest is measured over time. A study published in 2020 in Frontiers in Plant Science followed inflorescences in the dark for twelve months, stored at four temperatures, from minus 80 °C to 25 °C. Two figures sum up the result: mean terpenoid concentration had fallen by more than 50% as early as four months, at every temperature, while total phytocannabinoids lost an average of only 26% over twelve months. Whole inflorescences at 4 °C come out as the best condition, and ground samples oxidised more than whole buds.

Drying already costs dearly in aromas. Work published the same year in Foods measures on hemp flowers an essential-oil loss of 15 to 48% depending on the method, with sesquiterpenes holding up better than monoterpenes.

The ranking of the factors dates back to 1976. In the Journal of Pharmacy and Pharmacology, exposure to light, even out of direct sun, was named the leading factor in cannabinoid loss, the effect of temperature up to 20 °C judged of little significance, and oxidation in air credited with clear losses. Our guide on storing flowers draws the practical consequences.

A resin concentrates the trichomes, and therefore what degrades them too. The 1976 work brings a valuable distinction here: the cannabinoid loss caused by light does not raise cannabinol, whereas oxidation in air, in the dark, does. CBN is a marker of air and time, not of light.

A study published in 2025 in Scientific Reports put figures on that tipping across 150 resin samples from the Rif, seized by the Moroccan Royal Gendarmerie, kept for up to eight years in dry, dark premises between 20 and 25 °C, then quantified by gas chromatography. Fresh samples assayed at 35.16 ± 3.87% THC, 3.92 ± 0.40% CBD and 0.87 ± 0.35% CBN. After two years, THC had fallen to 2.74 ± 0.33%, CBN had risen to 6.94 ± 0.83% and CBD to 6.71 ± 0.77%. The authors describe first-order kinetics and keep the THC-to-CBN ratio as an indicator of storage duration.

Two reading precautions. Those illicit resins, very rich in THC, bear no comparison with a resin compliant with the French threshold: what carries over is the direction of the reaction, not the values. And that reaction consumes THC instead of producing it, so a resin starting at 0.2% does not cross the threshold as it ages. To the eye, oxidation reads in the colour, which darkens, and in the texture, which hardens: a full melt that no longer melts cleanly has aged.

With an oil, the format weighs as much as the storage. A study published in 2021 in Pharmaceutics followed CBD for a year, in the dark, in open and closed vials. At 25 °C and 60% relative humidity, the powder stayed statistically unchanged for 270 days, then lost 10.37 ± 0.51% in an open vial and 8.01 ± 0.67% in a closed one by the end of the year. The same CBD dissolved in sunflower oil held for at least 180 days, after which only 58.03% remained at twelve months, a mean loss of 41.97%.

A best-before date therefore does not transpose from one format to another: an oil ages faster than a solid, and rancidity in the carrier oil adds itself to the degradation of the cannabinoids. Our storage markers are set out in the article devoted to storing an oil.

Four observations regularly pass for an expiry when they are nothing of the sort.

• A faded aroma. Terpenoids lose more than half their concentration in four months, cannabinoids a quarter in a year.
• A resin that darkens. Colour follows oxidation and time. It tells you about age, never about compliance.
• Amber trichomes. Ambering is a state of trichome maturity, not a sign of unsoundness.
• A DDM gone by. That is a quality promise reaching its end, with no ban attached, unlike a DLC.

Only one observation calls a halt: mould, white or grey downy filaments, a cellar smell, a damp feel. Our guide to recognising mould shows what to look for. For a given batch, the answer is on the certificate signed by an ISO/IEC 17025 accredited laboratory, and the FAQ page says where to ask for it.

• Service-public.fr, DLC, DDM and freezing date
• Légifrance, code de la consommation, article L412-7
• Légifrance, décret n° 2022-1440 du 17 novembre 2022
• Légifrance, arrêté du 30 décembre 2021 (the 0.30% threshold)
• Regulation (EC) No 1223/2009, article 19 (DDM and PAO)
• ASTM D8197-22, water activity of dried flower
• Milay et al., Frontiers in Plant Science, 2020
• Fettoukh et al., Scientific Reports, 2025 (THC towards CBN)
• Fairbairn, Liebmann and Rowan, Journal of Pharmacy and Pharmacology, 1976
• Kwaśnica et al., Foods, 2020 (volatile composition)
• Kosović, Sýkora and Kuchař, Pharmaceutics, 2021
• ISO/IEC 17025, testing and calibration laboratories
• Phytogrammes, storing your CBD flowers
• Phytogrammes, storing a CBD oil