TempoLife › Features › Supplement reference: dose, evidence and forms
Supplements
23 supplements, each grounded in the NIH Office of Dietary Supplements fact sheets: what it is, what the evidence supports, typical doses and cautions. Claims the fact sheets do not support are simply absent.
Supplements are not medicines and this page is not medical advice. Doses that help one person can harm another — with medicines, kidney or liver conditions, pregnancy, or before surgery, talk to a clinician before starting anything. More is not better.
| Supplement | What it is | Typical dose |
|---|---|---|
| Creatine | A compound the body makes and stores mostly in muscle; supplementing raises muscle creatine stores. | Studied doses: 3-5 g per day; loading protocols use about 20 g/day in 4 doses for 5-7 days. |
| Magnesium | A mineral in hundreds of enzyme reactions: muscle and nerve function, energy, bone. | RDA: men 400-420 mg, women 310-320 mg per day. |
| Vitamin D | A fat-soluble vitamin the skin makes in sunlight; needed for calcium absorption and bone. | RDA: 600 IU (15 mcg) to age 70, then 800 IU (20 mcg). UL 4000 IU. |
| Omega-3s (EPA/DHA) | Polyunsaturated fats from fish oil or algae; structural fats of cell membranes. | No RDA for EPA/DHA; ALA: men 1.6 g, women 1.1 g per day. Many products supply 250-500 mg combined EPA+DHA per day. |
| Melatonin | The hormone the brain releases in darkness to time sleep. | Studied doses commonly 0.5-5 mg, taken 30-60 minutes before bed. |
| Iron | A mineral at the core of haemoglobin; moves oxygen in the blood. | RDA: men 8 mg, women 19-50 18 mg, pregnancy 27 mg per day. |
| Vitamin B12 | A vitamin needed for nerve function and red blood cell formation; only found reliably in animal foods. | RDA: 2.4 mcg per day. |
| Zinc | A mineral in immune function, wound healing and hundreds of enzymes. | RDA: men 11 mg, women 8 mg per day. UL 40 mg. |
| Vitamin C | A vitamin needed for collagen, cartilage and immune cells; also an antioxidant. | RDA: men 90 mg, women 75 mg per day. UL 2000 mg. |
| Calcium | The main mineral of bone; also needed for muscle and nerve signalling. | RDA: 1000 mg (19-50), women over 50 and men over 70: 1200 mg per day. |
| Protein powders (whey, casein, plant blends) | Concentrated milk or plant protein, mostly used for convenience or training. | No RDA specific to powders; total protein reference intake for adults is 0.8 g per kg of body weight per day, more for athletes (commonly 1.2-2.0 g/kg). |
| Probiotics | Live micro-organisms intended to add to the gut's own population. | No universal dose; products list colony-forming units (CFUs), commonly in the billions per dose. |
| Electrolytes (sodium, potassium) | Minerals lost in sweat that keep nerves and muscles working. | Potassium AI: men 3400 mg, women 2600 mg per day. Sodium: under 2300 mg is the general guidance. |
| Caffeine (supplement form) | The stimulant from coffee, tea and many pre-workouts. | Studied performance dose: about 3-6 mg per kg of body weight. |
| Beetroot juice (nitrate) | Dietary nitrate, which the body converts to nitric oxide. | Studied amounts commonly 70-140 ml of concentrated juice, 2-3 hours before exercise. |
| Beta-alanine | An amino acid that builds muscle carnosine, a buffer against acidity in hard efforts. | Studied doses: 4-6 g per day, often in split doses. |
| Sodium bicarbonate (baking soda) | A buffer that raises blood pH against the acid of all-out efforts. | Studied doses: 0.2-0.3 g per kg, 1-3 hours before the event. |
| Vitamin A | A fat-soluble vitamin for vision, immune function and cell growth; as retinol and as beta-carotene precursors. | RDA: men 900 mcg RAE, women 700 mcg RAE per day. |
| Vitamin E | A fat-soluble antioxidant vitamin. | RDA: 15 mg per day. UL 1000 mg. |
| Folate / folic acid | A B-vitamin needed for cell division; folic acid is the supplement form. | RDA: 400 mcg DFE; pregnancy 600 mcg DFE per day. |
| Iodine | A mineral the thyroid needs to make its hormones. | RDA: 150 mcg per day; pregnancy 220 mcg. |
| Selenium | A mineral that is part of antioxidant enzymes and thyroid function. | RDA: 55 mcg per day. UL 400 mcg. |
| Multivitamins | Combination products with no standard definition; contents vary product to product. | Follow the label; one product's dose says nothing about another's. |
Source: NIH Office of Dietary Supplements — fact sheets · checked 2026-09-03
Frequently asked questions
Who should take supplements?
People with a diagnosed deficiency, a restricted diet, or a specific need their clinician has identified. For everyone else, food first is the position the evidence — and the ODS fact sheets this page is built on — supports.
Are supplements safe?
Not automatically. They have real doses, real upper limits, and real interactions with medicines. Each item page carries its cautions from the fact sheet, and the rule stands: tell your clinician what you take.
Why does this page not promise results?
Because the fact sheets do not. Where the evidence is solid (correcting a deficiency, creatine with resistance training), the page says so; where it is thin, the page says that too.
Track what you take
TempoLife keeps supplements, food and sleep in one log — the complete picture a clinician needs at a glance.