Cistus incanus has been studied both as an herbal infusion and as an extract. These preparations were used in different kinds of research, so the results need to be read separately. [1] [2]
A trial of an extract for respiratory symptoms
In a 2009 randomised, placebo-controlled trial, 160 people with upper respiratory tract infections received CYSTUS052, a Cistus extract, or placebo. The researchers reported a greater reduction in subjective symptom scores in the extract group. [1]
The trial investigated a particular extract. It does not establish that a cup of commercially sold Cistus tea has the same effect. That is a limitation when applying this result to tea drinking. [1]
A small study of tea and blood markers
A pilot study published in 2021 followed 24 healthy adults drinking Cistus tea for 12 weeks. Researchers reported higher HDL cholesterol, lower triglycerides and changes in some markers of oxidative stress. Total and LDL cholesterol did not change significantly. [2]
All participants received the tea, and the study compared their measurements over time without a separate control group. It measured blood markers, not heart attacks or other clinical outcomes. These results cannot establish that the tea prevents cardiovascular disease. [2]
What did laboratory antiviral research find?
A 2016 study found that Cistus extracts inhibited HIV infection in cell experiments. Researchers also tested virus particles carrying Ebola and Marburg envelope proteins. These were laboratory experiments, not treatment trials in people. [3]
The finding does not show that drinking the tea prevents or treats those infections. It concerns the activity of extracts under the conditions of the experiments. [3]
What about safety?
The studies above do not establish safety for everyone. In particular, the tea pilot excluded people with chronic disease and those taking prescribed medicines. [2]
For herbal medicines, NHS guidance advises checking with a pharmacist if you take other medicines. It advises against their use during pregnancy or breastfeeding and in people with kidney or liver problems. This is general guidance on herbal medicines, not a Cistus-specific interaction study. [4]
If you are considering Cistus for symptoms or alongside treatment, discuss the product with a pharmacist or doctor. Do not stop prescribed medicine without speaking to your doctor. [4]
