SiS Vitamin D3 1000 IU

Science In Sport Vitamin D3

A daily Vitamin D3 tablet built for athletes, indoor trainees, and active adults who want to maintain healthy vitamin D levels year-round to support immunity, muscle function, and bone health. Particularly relevant for anyone whose lifestyle, schedule, or training environment limits consistent sun exposure — gym-based lifters, office workers, and athletes who train predominantly indoors.

What makes this a sensible daily choice comes down to dose accuracy and form. Each tablet provides 1000iu (25mcg) of vitamin D as D3 (cholecalciferol) — the form most efficiently absorbed and utilised by the body, identical to what your skin produces from UVB exposure. Many cheaper supplements still rely on the inferior D2 form, which the body converts and uses far less effectively. The 1000iu daily dose is a clinically appropriate maintenance level — enough to meaningfully support normal vitamin D status without going into the high-strength athlete-specific dose territory of 4000iu products. That makes it ideal for sustained daily use across the year, not just deficiency correction.

Science In Sport is a UK-based brand publicly listed on the London Stock Exchange (AIM: SIS) and manufactured to GMP standards. The brand's broader range is widely Informed-Sport certified for elite athletes, with batch-level testing across its performance line. For competing tested-pool athletes in Sri Lanka, always check the individual batch certification on the SiS website; for everyone else, the brand's pedigree as official supplier to multiple WorldTour cycling teams and Olympic federations underpins the product's credibility.

• 1000iu (25mcg) of vitamin D3 per tablet — a clinically appropriate daily maintenance dose for sustained use
• Uses cholecalciferol (D3) — the form most readily absorbed by the body, identical to what skin produces from sunlight
• Wide-ranging vitamin D3 benefits — supports immune function, normal muscle function, and normal bone health
• Convenient one-a-day tablet format — simple to dose, no measuring or mixing
• Among the best vitamin D3 supplements available in Sri Lanka for athletes and active adults — strong value at the vitamin d3 price in Sri Lanka category from a credible UK brand

Pair it with a daily multivitamin or Omega 3 from our vitamins and supplements range to round out a complete daily routine.