Supplement plan
Supplements aren't for everyone. If you eat well, you may need few or none. They exist to fill a gap, such as low vitamin D, a plant-based diet, a hard training load or a diet that skips a food group. Read what each one does and how strong the evidence is, tick only the ones that suit your needs, then choose morning, afternoon or evening and type in the brand and dosage from your own label. Your stacks, schedule and safety checks build as you go, and you can download the finished plan as a PDF or Excel file.
Learn the plan
This is not a prescription. More supplements isn't better. Most healthy people who eat well need few of them, and several items here have limited evidence. Choose only the ones you have a reason to take.
Talk to your GP or pharmacist first if you take any regular medicine, especially warfarin or other blood thinners, blood pressure tablets, nitrates, thyroid medicine, antibiotics or diabetes medicine. Also ask first if you have kidney disease, liver disease or a heart rhythm problem, are pregnant or breastfeeding, are under 18, or have surgery coming up.
Use your blood tests. Vitamin D, vitamin B12 and magnesium needs vary. Set doses from your results with your doctor instead of copying someone else's.
Choose products listed with the TGA (look for an AUST L or AUST R number on the label), and check the label for the actual amount of each active ingredient. Stop and see your doctor if you get an unusual reaction.
Your body makes glutathione, its main internal antioxidant, from three amino acids. Glycine and cysteine are the limiting ones, and NAC supplies cysteine. GlyNAC is the name for taking glycine and NAC together, with NAC in the morning and glycine at night in this plan.
What the research actually is. The headline results come from one research group at Baylor College of Medicine. Their randomised, placebo-controlled trial (Kumar et al., 2023) gave GlyNAC to 12 older adults and placebo to 12 for 16 weeks. A separate dose-ranging trial of 114 healthy older adults found GlyNAC safe and well tolerated, but the glutathione rise was mainly in people with high oxidative stress. These are small studies and need repeating by independent teams.
Dose gap. The Baylor trials used doses based on body weight that work out to several grams of each amino acid a day for an average adult. Typical shop supplements are lower (NAC is often 600 to 1,200 mg and glycine 3 to 5 g), so benefits seen in the trials can't be assumed at those doses.
The 18 reported benefits, rated
| Target | What the research shows | Evidence |
|---|---|---|
| 1. Heart and vessels | Baylor trial reported better blood vessel function and lower systolic blood pressure. | Limited |
| 2. Brain and thinking | A small pilot study reported better memory and cognition in older adults. | Limited |
| 3. Liver | NAC protects the liver in paracetamol overdose at medical doses. Benefit for everyday liver health is unproven. | Limited |
| 4. Kidneys | Human studies of NAC for kidney protection are mixed. | Limited |
| 5. Thyroid | Based on laboratory mechanisms only. No human GlyNAC trials. | Speculative |
| 6. Inflammation | Trial reported lower IL-6, TNF-alpha and hs-CRP. | Limited |
| 7. Oxidative stress, mitochondria | Trial reported lower oxidative stress markers and better mitochondrial markers. | Limited |
| 8. Homocysteine | Plausible mechanism. Human data are limited. | Limited |
| 9. Detox, heavy metals | Mostly laboratory and animal work. | Speculative |
| 10. Sleep | Glycine alone, 3 g before bed, improved sleep quality in small trials. It wasn't tested as GlyNAC. | Limited |
| 11. Muscle strength | Trial reported better grip strength and faster walking speed. | Limited |
| 12. Body composition | Trial reported smaller waist size. Fat and muscle changes are preliminary. | Limited |
| 13. Insulin sensitivity | Trial reported improved insulin resistance markers. | Limited |
| 14. DNA damage | Trial reported lower DNA damage markers. What this means for health is unknown. | Limited |
| 15. Exercise capacity | Trial reported improved exercise capacity measures. | Limited |
| 16. Immune function | Plausible, since immune cells need glutathione. No GlyNAC trial. | Speculative |
| 17. "Reversing aging hallmarks" | One small trial in older adults with a BMI over 27. "Reversal" overstates what was measured. | Limited |
| 18. Antioxidant reserve | Glutathione rose in trials. The rise was mainly in people with high oxidative stress. | Limited |
Each supplement is checked three ways: what the trials show, what sports dietitians and nutritionists advise, and what coaches and trainers say in practice. Coaching views come from general practice, not formal studies, so we show them next to the research, not instead of it. Tap a name to open it.
- Well establishedConsistent trials or reviews, and official guidance, for the stated purpose.
- ModerateSeveral trials or reviews with modest or variable effects.
- LimitedFew, small or mixed studies. Fine to try, with realistic expectations.
- SpeculativeA plausible mechanism, but no human trials.
Where coaches and evidence disagree. Fish oil is the clearest case. Coaches rate it highly and the trials support that for low fish intake, triglycerides and, modestly, recovery. They don't support it as a heart-protecting pill for healthy people. A label shows the purpose it's backed for, not whether it's worth taking.
- Fat-soluble items with food. Take vitamin D3, vitamin K2, CoQ10 and omega-3 with a meal that has some fat, such as breakfast, lunch or dinner. Fat in the meal helps absorption. B vitamins and the multivitamin can go with the same meal.
- Use the afternoon stack to space things out. If two items compete for absorption (see the clash table below), put one at breakfast or lunch and the other with dinner or before bed.
- Split the NAC. One dose with your early electrolyte drink and one with breakfast. Food proteins help protect the stomach from NAC's acidity, and two doses give a steadier supply of cysteine.
- Creatine and collagen in your morning shake or coffee. Either works. For creatine, the daily habit matters more than the exact time.
- Berberine with meals. Take it with food, not on an empty stomach, to ease stomach upset. Trials split 0.9 to 1.5 g a day across meals, so spread doses over the day instead of taking them all at once.
- Magnesium and glycine before bed. Take them 30 to 60 minutes before sleep. If magnesium citrate loosens your bowels overnight, move it earlier in the day.
- Drink plenty of water. NAC and magnesium both rely on good hydration. See the hydration plan.
- Separate from some medicines. Magnesium and multivitamin minerals can reduce absorption of thyroid medicine and some antibiotics. Leave 2 to 4 hours between them and ask your pharmacist about your medicine.
Common clashes and how to space them
Some supplements and minerals compete for absorption, and some medicines bind to minerals. Moving one of the pair to a different part of the day, which is what the afternoon stack is for, fixes most of them. Your cautions panel flags the ones that apply to your stacks.
| Combination | What happens | What to do |
|---|
Pairs that work well. Vitamin D3, vitamin K2 and omega-3 with a meal that has some fat. Iron with vitamin C. Vitamin D alongside enough calcium from food for bone health.
Mineral interactions are mostly about big single doses taken together. Food-sized amounts rarely matter, so the aim is to keep concentrated supplements apart, not to avoid food combinations.
| Nutrient | Upper limit or key fact |
|---|---|
| Vitamin D | Australia (NHMRC): 80 µg, or 3,200 IU, a day for adults. USA (Institute of Medicine) and Europe (EFSA): 100 µg, or 4,000 IU. Limits count all sources, including your multivitamin. |
| Magnesium | This page asks you to keep your total magnesium from food and supplements combined at or under 420 mg a day. Separately, the official upper limit for supplements alone is 350 mg a day of elemental magnesium (NHMRC and USA). Both count every form together (citrate, glycinate and complex), so add up all your products and your food. Higher doses commonly cause diarrhoea, mostly with citrate and oxide. Kidney disease raises the risk. |
| Fish oil (EPA + DHA) | No Australian upper limit, but a 2021 meta-analysis of 7 trials linked more than 1 g a day to a 49% higher atrial fibrillation risk, and 1 g or less to 12% higher. |
| Vitamin K2 | No upper limit set, but it works against warfarin even at low doses. It isn't thought to affect newer blood thinners such as apixaban or rivaroxaban. |
| B vitamins | Vitamin B12 has no upper limit set, and excess is generally excreted. Folic acid: 1,000 µg a day from supplements and fortified foods (NHMRC), and treat L-methylfolate the same way. Vitamin B6: 50 mg a day (NHMRC), because long-term high doses can damage nerves, so check your B-complex label. Large folic acid doses can hide B12 deficiency. |
| NAC | Oral doses of 600 to 1,200 mg a day are typical. Common side effects are nausea, diarrhoea and a sulphur smell. Can strengthen nitrates and cause low blood pressure and headaches. |
| Creatine | 3 to 5 g a day has been studied for years in healthy adults with no kidney harm. It raises blood creatinine, which can confuse kidney tests, so tell your doctor. |
| Aged garlic, fish oil | May add to the effect of blood thinners. Tell your surgeon or dentist before procedures. |
| Berberine | No upper limit set. Trials ran 1 to 3 months at 0.9 to 1.5 g a day, so long-term safety data are limited. Common side effects are diarrhoea, constipation, nausea and cramps. It lowers blood sugar, can raise cyclosporine levels sharply and affects how the liver clears several other medicines. Not recommended in pregnancy or breastfeeding. |
| CoQ10 | Case reports of weaker warfarin effect, though one controlled trial found no change. Treat as a possible interaction. |
Where the source plan overstates. It describes fish oil as safely reducing "body-wide inflammation". Its effect on inflammation is modest, so we've rated it conservatively. Likewise, vitamin D at 4,000 IU a day equals the US and EU upper limit but exceeds Australia's.
Magnesium adds up. If you use the electrolyte mix, its small amount of magnesium (about 10 mg a serve) counts towards your total. The upper limit for supplements is 350 mg of elemental magnesium a day, counting all forms together. Magnesium from food counts towards your 420 mg daily total too.
How this page was checked
What we checked, and what we changed
Each item's claim and safety note was compared with published trials, official nutrient reference values and drug interaction information. Where a claim from the original plan was stronger than the evidence, we softened it and tagged it.
Doses: this page doesn't suggest a dose for any supplement. You type the brand and the amount from your own label, and they flow through to the PDF and Excel file exactly as you entered them. Limits for vitamin D and fish oil show up as reminders, so check your labels yourself. Magnesium is the exception: the page adds up the amounts you type for your magnesium products and warns you if they pass 420 mg a day. Food magnesium isn't counted, so allow for it.
Vitamin D: an average of 4,000 IU a day equals the US and EU upper limit but is above Australia's 3,200 IU. In healthy adults who aren't deficient, a large trial (VITAL) found no benefit for fractures, cancer or heart events. Use your blood test and your doctor to choose a dose.
Fish oil: "triple strength" softgels often contain around 1 g or more of EPA + DHA each, so two can pass 1 g a day. Check the label. A 2021 meta-analysis linked doses above 1 g a day to more atrial fibrillation.
Aged garlic: in an Australian trial of people with high blood pressure, 240 mg a day didn't lower blood pressure and 480 mg did, so check the amount on your product.
GlyNAC: 18 benefits were rated individually. Most come from one research group's small trials, and a few have no human trials. "Speculative" means a mechanism without human evidence.
Berberine: a 2024 meta-analysis of 50 randomised trials found modest drops in blood sugar, LDL cholesterol and triglycerides, mostly in people with type 2 diabetes. Trials were short and varied in quality, so we've rated it "limited". The interaction and pregnancy cautions come from drug-information references and case reports rather than large trials, so we've kept them cautious.
Magnesium forms: citrate and glycinate both absorb much better than magnesium oxide. Whether glycinate absorbs better than citrate isn't settled, so we say so. Glycinate is gentler on the gut and citrate is mildly laxative. Sleep and mood claims for glycinate come from small trials, so we've kept them modest. Evidence on blended "complex" products is thinner, so we rated that card "limited". The limit of 350 mg elemental magnesium applies to all forms combined.
Evidence labels: we re-read the evidence for every item, using the AIS Sports Supplement Framework, the IOC consensus statement, ISSN position stands, NIH Office of Dietary Supplements fact sheets, Cochrane reviews and recent meta-analyses. Labels now say what the evidence supports. "Well established" means consistent trials or reviews for the stated purpose, "Moderate" means several trials with modest or variable effects, "Limited" means few, small or mixed studies, and "Speculative" means mechanism only. The Evidence in depth section shows the reasoning and references for each item.
Omega-3: we changed its label from "Limited" to "Well established for triglycerides and low intake". Cochrane found a clear triglyceride reduction, and fish oil is a sensible way to top up a low intake. Its effect on heart events in healthy people is little or none, and its benefit for recovery is emerging and modest. The label says which purpose it's backed for. Coaches' enthusiasm is real, but we show it next to the trials, not as proof.
B vitamins: the single B12 item is now three choices: B12, folate and a B-complex, each listed in a methylated form (methylcobalamin, L-methylfolate). Cyanocobalamin has the most trial evidence and is converted by the body, and no strong trials show methylated forms are better in people without a specific need. We list methylated forms as the preferred choice and say so. Choose forms and doses from your blood tests.
Spacing rules: the clash table comes from NIH fact sheets and published reviews. Most mineral clashes involve large single doses, so we flag them for supplements and keep the language measured.
Your own entries: supplements you type in are shown in your stacks and PDF, but they aren't rated or dose-checked. We only match keywords such as calcium, iron, zinc, magnesium and vitamin K to show spacing and medicine cautions.
Benefit lines: the short benefits on each supplement card are plain-language summaries of the ratings on this page. Where evidence is limited, the card says so under "Worth knowing".
Our judgement Ratings of "well established", "limited" and "speculative" are our summary of the evidence, not an official grading. The multivitamin, collagen and CoQ10 ratings reflect small or mixed trials. This is general information, not medical advice.
Sources and further reading
NHMRC, Vitamin D: nutrient reference values for Australia and New Zealand
NIH Office of Dietary Supplements, Vitamin D fact sheet
VITAL trial findings: vitamin D and omega-3 in healthy adults
Circulation (2021): marine omega-3 supplementation and atrial fibrillation, a meta-analysis
Kumar et al. (2023): GlyNAC in older adults, a randomised clinical trial
Frontiers in Aging (2022): glycine and NAC dose-ranging trial in healthy older adults
Bannai et al. (2012): glycine and sleep in sleep-restricted volunteers
Wang et al. (2024): berberine and type 2 diabetes, a systematic review and meta-analysis
NHMRC, Magnesium: nutrient reference values for Australia and New Zealand (PDF)
Australian Institute of Sport: Sports Supplement Framework
IOC consensus statement: dietary supplements and the high-performance athlete (2018)
ISSN position stand: safety and efficacy of creatine supplementation (2017)
NIH Office of Dietary Supplements: vitamin B12
NHMRC, Vitamin B6: nutrient reference values (PDF)
Iron and zinc homeostasis and interactions (review)
Dietitians Australia: find an accredited practising dietitian
More references for each item are listed under Evidence in depth.
Routines and protocols that tie the plan together.