A new human study published in Scientific Reports finds that older adults have measurably lower endocannabinoid levels at baseline compared to younger adults, and that acute cannabis use produces proportionally larger increases in those same compounds in older users. For a physician whose practice focuses on aging patients and the endocannabinoid system, this is one of the most clinically meaningful pieces of mechanistic data published in 2026.

Older adults are the fastest-growing demographic of medical cannabis patients in the United States, drawn primarily by pain, sleep difficulties, and the symptoms of age-related decline. What this research offers, for the first time in a human study, is a biological mechanism that may help explain that trend: the endocannabinoid system appears to lose tone with age, and cannabis use appears to partially restore it, with older adults showing larger responses to the same acute exposure. This has real implications for how clinicians understand dosing, expected response, and the biological rationale for cannabis in aging populations. Massachusetts physicians and patients in particular should take note.

Published in Scientific Reports in January 2026, this study by Morris, Mueller, Sempio, Klawitter, Bryan, Bidwell, and Hutchison at the University of Colorado recruited 142 adults across three age cohorts: younger (21–24 years, n=38), midlife (25–54 years, n=73), and older (55–71 years, n=31). All participants reported cannabis use at least four times in the prior month. Blood samples were taken before cannabis use and again approximately one to two hours afterward, depending on whether the product used was flower or an edible. Seven endocannabinoid compounds were measured using mass spectrometry: anandamide (AEA), 2-AG, and five related N-acylethanolamines (DEA, LEA, PEA, SEA, OEA). The study’s design was secondary analysis of two prior trials using dispensary-sourced cannabis products across THC-dominant, CBD-dominant, and balanced formulations. (Morris AWJ et al., Scientific Reports, 2026; vol. 16, Article 3483. DOI: 10.1038/s41598-025-27618-1)

At baseline, older adults had significantly lower plasma AEA, DEA, and LEA compared to younger adults. Following acute cannabis use, five of the six N-acylethanolamines increased significantly across all age groups; 2-AG did not increase and actually declined slightly. Critically, older adults showed larger proportional increases in AEA and DEA than younger adults, with post-to-pre ratios of approximately 2.0 in the older group versus 1.4 in younger adults for AEA. Product type, whether flower or edible, THC-dominant or CBD-dominant, did not materially alter these findings after statistical correction. The authors concluded that endocannabinoid tone differs across the lifespan and that cannabis acutely modulates this system in all age groups, with suggestive evidence for greater responsivity in older adults.

Your Body’s Own Cannabis System Gets Quieter With Age. Here Is What That Means in the Clinic.

When an older patient sits across from me and says they have tried everything for their pain, or their sleep, or the low-level inflammation that has become a constant companion, and that cannabis seems to help in ways that other things have not, I take that seriously. I always have. But the question I am asked most often, by patients, by colleagues, by family members trying to make sense of what they are observing, is: why? Why would cannabis work differently for someone in their sixties than for someone in their thirties? This paper, for the first time in a human study with blood measurement, gives me a biological answer to work with.

The endocannabinoid system is the body’s primary regulatory network. It governs pain signaling, mood, sleep architecture, immune tone, appetite, and dozens of other processes through two main receptors, CB1 and CB2, and through endogenous ligands that the body manufactures on demand. Anandamide, often called the “bliss molecule,” is the most studied of these. 2-AG is the other primary endocannabinoid. Both bind to the same receptors that THC engages, which is why cannabis can affect pain and sleep and mood: the plant compound is activating the same machinery the body uses for those purposes natively.

The preclinical literature has been telling us for years that this system loses tone with age. CB1 receptor expression drops in the aging brain. Baseline anandamide levels decline. The enzymatic processes that produce endocannabinoids shift as lipid metabolism changes with age. What we have not had, until now, is a human study measuring these compounds in the blood of older adults before and after real-world cannabis use from dispensary products. That gap matters. Animal models tell you about mechanisms; human plasma data tells you about patients.

What Morris and colleagues found is exactly what the preclinical story would predict, and then some. Older adults arrived at the study with lower baseline AEA, DEA, and LEA than younger adults. After cannabis use, their anandamide levels roughly doubled. In younger adults, the same exposure produced only about a 40% increase. That is not a small difference. The older ECS, running low to begin with, appears to respond more forcefully to exogenous cannabinoid stimulation. The system is not inert, it is depleted, and it can still respond when given the input it is no longer generating internally at the same level.

There are important nuances to how I read this clinically. The study is observational. It was not designed to test whether the endocannabinoid changes produced measurable clinical outcomes like reduced pain or improved sleep. We do not know from this data whether the larger AEA increase in older adults translates into greater therapeutic effect, greater psychoactive effect, or both. What we do know is that the biological substrate is different across age groups, and that this difference has been measured in real patients using real legal-market products. That is the start of a more grounded clinical conversation, not the end of it.

The dosing implications deserve attention. If older adults’ endocannabinoid systems are more responsive to acute cannabis input, that has direct practical consequences for how we approach initiation in older patients. Start low, go slow is the right framework not merely as general caution, but for a biochemical reason that this paper illuminates: the system in an older body may respond more intensely to a given dose than the same dose would produce in a younger person. This is consistent with what I observe clinically. Older patients often report effects at doses that younger patients find underwhelming. This study offers a plausible mechanism for that observation.

One finding deserves a separate note because it is genuinely unexpected: 2-AG did not increase after cannabis use and actually declined slightly. AEA and 2-AG are both endocannabinoids and both engage CB1 and CB2, but they are produced by different enzymatic pathways and respond differently to physiological inputs. THC engages the same CB1 receptor that 2-AG normally activates, and there is evidence that exogenous CB1 activation can suppress endogenous 2-AG production through feedback inhibition. If THC is effectively substituting for 2-AG at the receptor level while simultaneously reducing the signal for the body to produce more 2-AG, that is a meaningful distinction from what happens with AEA. The clinical implications are not yet clear. But it is the kind of mechanistic detail that matters for long-term use discussions.

The broader takeaway for practice is this: aging appears to create an endocannabinoid deficiency that is measurable in human blood, cannabis appears to partially address that deficiency acutely, and older adults appear to be more pharmacodynamically responsive to cannabis than younger adults at the biological level. None of that is a prescription. But it is the kind of mechanistic grounding that makes the clinical conversation with older patients, the one where they ask why this seems to work for them when other things have not, more honest and more specific than it has been before.

The theory of clinical endocannabinoid deficiency, proposed by Ethan Russo and supported by a growing body of human biomarker data, holds that reduced ECS tone may underlie treatment-resistant conditions including migraine, fibromyalgia, and irritable bowel syndrome. A 2007 study in Neuropsychopharmacology found lower anandamide in the cerebrospinal fluid of chronic migraine patients; subsequent work has replicated versions of this finding. The Morris et al. study extends this line of reasoning to aging specifically, measuring plasma endocannabinoids rather than CSF levels, using a real-world dispensary-product design rather than a laboratory setting. It is the first study to combine both the age comparison at baseline and the acute response measurement in the same human cohort. Earlier work by the same group, including Bidwell et al. published in JAMA Psychiatry in 2020, established some of the foundational methodology for measuring cannabis effects using real-market products in naturalistic settings.

From a safety standpoint, the enhanced responsivity of the aging ECS to cannabis has direct clinical relevance. Older adults are more likely to be on medications metabolized by the CYP450 system, including warfarin, certain statins, and anticonvulsants, where cannabinoid-induced inhibition can meaningfully alter drug concentrations. They are also more likely to have baseline gait instability or orthostatic hypotension, conditions where any additional CNS or cardiovascular effect from cannabis warrants attention. The practical recommendation: for older adults initiating cannabis for any indication, starting at the lowest available dose with extended uptitration intervals is not conservative caution, it is mechanistically appropriate given what this study suggests about differential biological responsivity.

This is a secondary analysis of two prior naturalistic studies, meaning the data were collected for different primary purposes and re-analyzed here through an age-differentiated lens. The strength of this design is ecological validity: participants used actual dispensary products in real-world conditions. The limitation is reduced experimental control. Abstinence at baseline was not confirmed by blood test, so some “pre-use” samples may have included residual cannabinoids from recent prior use. Age bins are broad, particularly the midlife group spanning 25 to 54 years. There is no non-user control group, so we cannot determine whether the lower baseline endocannabinoid levels in older cannabis users would look different from older non-users. These are meaningful caveats for a mechanistic study. They do not undermine the findings, but they define the boundaries of what this study can and cannot claim.

This paper sits at the intersection of two converging bodies of research: the preclinical literature on ECS aging (Di Marzo et al., Nature Reviews Neuroscience, 2015; Bilkei-Gorzo et al., PNAS, 2005) and the growing clinical evidence base for cannabis use in older adults. A 2020 study in JAMA Internal Medicine found that cannabis use among adults over 65 increased fivefold between 2015 and 2018. The rise in older adult cannabis use has largely outpaced any mechanistic explanation for why this population might respond differently. This study provides the first human plasma data suggesting that the answer may lie in baseline ECS tone and differential acute responsivity. It does not prove clinical benefit — that requires prospective randomized trials with clinical outcomes — but it provides the mechanistic scaffolding that makes such trials worth designing and running.

Yes, in both directions. A stricter abstinence protocol with biochemical verification would reduce the risk that residual cannabinoids contaminated baseline measurements, potentially strengthening or narrowing the age differences observed. A continuous rather than binned age variable might reveal a more gradual decline curve than the three-group comparison shows. Including a non-user comparison group would clarify whether older cannabis users have lower ECS tone than age-matched non-users, or whether all older adults show this pattern regardless of cannabis use history. The authors ran extensive sensitivity analyses including form, composition, BMI, years of use, and age of first use, and the primary findings held. That robustness increases confidence in the core result.

Misreading 1: “This proves cannabis is good for older adults.” It does not. It identifies a biological mechanism that may explain differential response patterns. Clinical benefit requires clinical outcome data, which this study did not measure.

Misreading 2: “2-AG going down means cannabis depletes the ECS.” 2-AG and AEA are produced by different pathways and respond differently to exogenous cannabinoid input. The decline in 2-AG may reflect receptor-level feedback rather than systemic depletion. This is mechanistically complex territory that the study is not designed to resolve definitively.

Misreading 3: “Older adults should use more cannabis because they respond more.” Greater pharmacodynamic responsivity is a reason for more careful, lower-dose titration, not a license to increase intake. Enhanced sensitivity cuts both ways.

Aging appears to lower endocannabinoid tone in measurable ways, and cannabis acutely restores it with larger effects in older adults than younger ones. This is the first human study to demonstrate this directly with plasma endocannabinoid measurements before and after real-world cannabis use across age groups. It provides biological grounding for a clinical pattern many physicians have observed but lacked mechanistic language to explain. It is a starting point for properly designed trials with clinical endpoints, not a therapeutic recommendation on its own. But it is the kind of mechanistic clarity this field has needed and too rarely had.

Q: Does this mean cannabis is safe for older adults?
This study measured endocannabinoid biomarkers, not safety outcomes. What it adds is biological context: older adults appear to have lower baseline endocannabinoid tone and show larger acute responses to cannabis. That makes careful titration especially important in this population, not less. Speak with your physician before starting any cannabis regimen, particularly if you are on other medications.

Q: My parent/grandparent uses cannabis for pain or sleep. Does this explain why it seems to help?
Possibly, in a mechanistic sense. If their endocannabinoid system has less activity at rest than it did when they were younger, cannabis may be partially restoring a signaling capacity that has diminished. Whether that translates into meaningful clinical relief for specific symptoms is something that properly designed clinical trials still need to establish. But the biological mechanism is consistent with what patients report.

Q: Should older adults use more cannabis because they need it more?
No. This study suggests older adults are more pharmacodynamically responsive to the same dose. The clinical implication is the opposite of what that question implies: start at lower doses, titrate more slowly, and give the system time to reach a new equilibrium before adjusting upward. Greater responsivity is a reason for more precision, not more product.

Have thoughts on this? Share it: