Immune Support

A USP Verified 2,000 IU vitamin D3 softgel in soybean oil for about 6 cents a day, the no-frills benchmark for daily vitamin D.

A small, NSF-certified 15 mg zinc picolinate capsule dosed near the RDA; TikTok-famous for skin anecdotes, and best paired with copper for long-term use.

1,000 mg of vitamin C with rose hips in a sustained-release tablet for about 6 cents a day; far more than most people need, but cheap and cleanly made.

One capsule of 10 billion CFU Lactobacillus rhamnosus GG plus 200 mg inulin, with potency guaranteed to expiration, for about 60 cents a day.

Amazon's top D3+K2 pick: vegan lichen D3 plus MK-7 K2 in coconut MCT oil; the 5,000 IU dose exceeds the adult upper limit for daily use.

NSF Certified for Sport greens drink with a full multivitamin and 10 billion viable cells of five named probiotics, but over $3 a scoop with two proprietary blends.

Amazon's mega-seller: 60 billion CFU from 10 species plus prebiotic fiber, third-party tested and cheap. But it names no strains, so it can't be matched to research.

A USDA Organic, grass-fed dairy shake with 250 calories, 16 g of protein and 20 vitamins and minerals; closer to a light meal than most shakes, but low in fiber.

Two of the best-studied probiotic strains (LGG, BB-12) at 11B CFU guaranteed to expiration, plus a phage prebiotic and tributyrin. Top testing, premium price.

One of the longest-selling greens powders: 5.4 g of grasses and greens plus a studied probiotic for under $1 a scoop, with plain-grassy taste and a Prop 65 lead warning.

A viral daily pack of greens gummies that delivers a real multivitamin and 6 g of fiber, but the 'superfoods' sit in one 8.7 g blend and the original has 8 g added sugar.

A cheaper AG1 alternative with 7.3 g of organic greens and 5 billion CFU of named probiotics, but a January 2026 Class I Salmonella recall weighs heavily on trust.