The minimum is 16,000 years ago, which would still be the oldest direct evidence of drug use by a substantial margin.

Whether the individual lived closer to 25,000 years ago or closer to 16,000 years ago is not determined by the available evidence.

What is determined is that they predated agriculture on Sulawesi by a significant margin regardless — agriculture reached Sulawesi only within the last 4,000 years or so, meaning that even the most conservative dating of this specimen places the betel nut use well before farming.

The Younger Specimen: CPL-R2a