Vitamin C is one of the most scientifically proven natural antihistamines out there, and the most widely available.

In 2023, a big review of 139 papers found that vitamin C can offer powerful anti-allergy effects for people suffering from allergic and immune-system-related conditions. Ultimately, the study concluded that vitamin C was effective because it offers anti-inflammatory and antioxidant effects, helping to relax the throat muscles, which often constrict during an allergic response.

The effects of vitamin C are particularly powerful when the vitamin is delivered in concentrated doses: a 2018 study found that high-dose intravenous vitamin C eased allergy symptoms, while another piece of research published in 2000 found that taking 2,000mg of vitamin C a day could reduce histamine levels.

4 natural antihistamines that could help ease hay fever symptoms