UK Supplement Trends — October 2025: the immune build begins

Part of The Formulation Index, Supplement Factory’s monthly read on what UK brands are actually briefing us to make.

October is when the UK supplement market turns its collar up. After a quieter September, demand across our formulation quotes swung hard toward the immune stack, and the numbers show it in one clean move.

Magnesium reclaimed the top spot, appearing in 53% of the formulations we quoted, up twenty-three points on the month. But the real story sat underneath it. Zinc jumped thirty points to 38%. Vitamin D3 rose twenty-five to 31%. Vitamin C climbed to 41%. And Selenium, the quiet one, surged twenty-six points to 32%, its strongest showing of the year. When four immune-associated actives move together like that, it is not coincidence. It is the trade briefing winter products in the window before the cold season lands.

Ingredient in focus: Selenium

Selenium spends most of the year as a supporting player, quietly folded into comprehensive multivitamins rather than headlining. In October it stepped forward. Its jump to nearly a third of all quotes tracks a shift we see every autumn: brands moving from everyday wellness toward targeted immune support, and reaching past the obvious vitamin C and zinc for the trace minerals that round out a credible immune claim. For a brand, Selenium is a low-cost, high-credibility addition that signals a formulation built with intent rather than assembled from the usual suspects. If it is not in your immune brief, it is worth asking why.

What else moved

Beyond the immune block, the month carried an energy undercurrent. Taurine climbed to 24% and Rhodiola to 13%, both pointing to the growing overlap between immune season and the “get me through winter” energy category. Magnesium’s dominance, meanwhile, continued to reflect the sleep and recovery megatrend that has underpinned the whole year.

What it means for brands

October’s data carries a simple planning lesson. Immune demand does not appear in winter; it is committed to in autumn, weeks or months before a product reaches a shelf. By the time consumers are searching for immune support in December, the brands that will meet that demand briefed their formulations in September and October. If you are planning an immune or winter-wellness product, this is the rhythm to plan against: brief early, and build around a stack that goes beyond vitamin C and zinc to the trace minerals, Selenium among them, that make an immune claim stand up.

The base is set for a strong winter. In next month’s edition, we will see whether the immune build held or whether the market moved on.

The Formulation Index is built from Supplement Factory’s own formulation quotes, actives only, each ingredient counted once per quote. Explore the live Index →