Delta-8, Delta-9, Delta-10, where do we begin? The potent effects of Delta-9 tetrahydrocannabinol (most commonly referred to as just THC) are well known throughout the world. It was until recently that the awareness of Delta-8 tetrahydrocannabinol (D8) and Delta-10 tetrahydrocannabinol (D10) began to rise and gain mainstream popularity, despite being discovered and studied back in the 1980s.
These new, yet not really new, cannabinoids are being discussed regularly among consumers, businesses, and governmental regulatory agencies. If D8 or D10 have not been restricted in your state, then they remain in a somewhat legal grey area, but let’s look at how their effects compare to each other. Starting with THC as a baseline, THC is known to give consumers a great sense of euphoria, an uplifted mood, and potentially work as a sedative or energizer depending on the cannabinoid and terpene profiles. Some consumers also report feelings of paranoia and anxiety.
When compared to THC, the consensus among anecdotal reports from consumers throughout numerous media outlets regarding D8 is that its effects are similar to THC but less potent. The same goes for the effects of D10. When compared to THC, D10 is commonly said to provide effects resembling THC, but with less potency. However, there is published research that supports D10 being less potent than THC, but the study was performed on pigeons, and no human trials yet exist. 
Without much science to support an accurate comparison of the effects of D8 and D10 to THC, or each other, we are mostly left to public opinions. “Anecdotal evidence suggests delta-10-THC mirrors THC’s sativa side, while delta-8-THC recreates its indica aspect”.  Although sativa and indica are known by experts to not influence the effects of the plant, the general public is still under the impression that sativas are more energetic and indicas are more sedative. With that understanding, it’s safe to assume that D8 is being reported as more sedative than D10, but less than THC. In the same respect, D10 is being reported as more energizing than D10, but less than THC. In the end, there isn’t much scientific proof on the subject. Until science catches up with the anecdotes, all we have to go on are the opinions consumers are willing to share.
1 – Jarbe, T. et al., Separation of the discriminative stimulus effects of stereoisomers of Δ2- and Δ3-tetrahydrocannabinols in pigeons. European Journal of Pharmacology. 1988. 156, 361-366. https://www.academia.edu/23017075/Separation_of_the_discriminative_stimulus_effects_of_stereoisomers_of_%CE%942_and_%CE%943_tetrahydrocannabinols_in_pigeons
2 – Petrov, P. Delta-10-THC: The New THC Isomer. Delta 8 Magazine. 2021. https://delta8magazine.net/2021/05/31/delta-10-thc-the-new-thc-isomer/