Decreased sperm motility was observed in both fractions in response to Δ9-THC concentrations, mimicking those attained non-medically (0.32 and 4.8 μM), and in the 45% fraction in response to Δ9-THC concentrations typically seen therapeutically (0.032 μM). Inhibition of the acrosome reaction was only observed at the highest Δ9-THC concentration tested (4.8 µM) in the 90% fraction, while the 45% fraction displayed decreased acrosome reactions at all three Δ9-THC concentrations tested. Such effects raise the possibility that cannabis (i.e. Δ9-THC) can impair crucial sperm functions and male fertility, especially in those males already on the borderline of infertilityReference 1480. There are increasing reports of hypersensitivity/allergic reactions to cannabisReference 365Reference 393Reference 394Reference 1353Reference 1354. Clinical symptoms of such reactions include sore throat, nasal congestion, rhinitis, conjunctivitis, pharyngitis, food allergy, eczema, contact urticaria, anaphylaxis, wheezing, dyspnea, palpebral angioedema and lacrimationReference 365Reference 393Reference 1353.

The authors reported the absence of any modulatory effect of CBD (or other components of cannabis) at low therapeutic cannabinoid doses, with the potential exception of the subjective "high"Reference 122. A study from Norway, on apprehended drivers, demonstrated that THC- positive drivers had higher mean pulse rate than THC-negative drivers and surprisingly, the magnitude of tachycardia was independent of blood THC concentration hemp oil for pain . Cannabis use has also been shown to be associated with development of atrial fibrillation especially in young patients who don’t have any risk factor . In a systematic review of 6 case reports, Korantzopoulos et al. concluded that marijuana smoking might be associated with atrial fibrillation.

In one case report, a 19-year old man who overdosed on an edible cannabis product (i.e. a cannabis cookie) began reportedly exhibiting erratic speech and hostile behaviours within the first 2.5 h following consumption and died from bodily trauma resulting from a jump from a balcony approximately 3.5 h following consumption of the edibleReference 174. Only one clinical study has thus far been carried out looking specifically at the safety of THC in an elderly population. In this study, 12 adults aged 65 and older who were deemed to be healthy were included, and exclusion criteria included high falls risk, regular cannabis use, history of sensitivity to cannabis, drug and alcohol abuse, compromised cardiopulmonary function, and psychiatric comorbidities. The most commonly reported health problems were hypertension and hypercholesterolemia and subjects reported using an average of 2 medications (e.g. lipid-lowering drugs, aspirin, and beta-blockers).

There are a few pre-clinical reports which suggest that administration of a low dose of THC, a CB1 receptor antagonist, or a CB2 receptor agonist may reduce the progression of atherosclerosis in mouse models of the diseaseReference 1342-Reference 1344. Oral administration of THC (1 mg/kg/day) has been associated with significant inhibition of disease progression in the apolipoprotein E (ApoE) knockout mouse, a mouse model of atherosclerosisReference 1342. The beneficial effect of THC in this study was mediated by the CB2 receptor, likely through its inhibitory effects on immune system cells (macrophages and T-cells) located in or near atherosclerotic lesions. These findings were supported by another study that showed that intraperitoneal administration of a synthetic CB1/CB2 receptor agonist significantly reduced aortic plaque area in the ApoE knockout mouseReference 1344.

CBD has been getting a lot of buzz recently, showing up in products like oils, salves, gummies, and lotions. It’s been touted as a substance that can have a positive effect on conditions like anxiety, chronic pain, and even heart disease.