Daily Health Digest

By Only Health Editorial Team

A practical, source-backed guide to choosing gummies, capsules, powders, effervescent tablets, or liquids without mistaking a delivery format for proof of benefit.

By Only Health Editorial Team

Zinc supports essential body functions, but more is not automatically better. Here is how to read elemental zinc, compare food and supplement sources, and avoid common dosing mistakes.

By Only Health Editorial Team

A food-first, source-backed guide to calcium intake, vitamin D, bone health, supplement limits, and how to read a New Zealand calcium label.

By Only Health Editorial Team

Most healthy adults in New Zealand do not need a vitamin D supplement. This guide separates the well-supported skeletal benefits from marketing claims that run ahead of the evidence, using the Ministry of Health's sun exposure consensus statement, bpacnz's 2025 clinical update, Osteoporosis New Zealand, the NHS, and Harvard T.H. Chan School of Public Health.

By Only Health Editorial Team

Biotin, collagen, and keratin sit on the same beauty labels but rest on very different levels of evidence. A sourced guide to what each ingredient actually does, what trials show for hair, skin, and nails, why high-dose biotin can distort lab tests, and when hair shedding needs a doctor instead of a supplement.

By Only Health Editorial Team

Ashwagandha has real trial support for sleep and stress, plus a growing list of published liver injury case reports. Here is what NCCIH, NIH LiverTox, and the actual randomized trials say, dose by dose.

By Only Health Editorial Team

Melatonin, magnesium, L-theanine, and valerian all get marketed as sleep fixes, but the evidence behind each is different and often more limited than the label suggests. A sourced guide to what actually helps, what the routine basics change first, and when to see a clinician instead.