Supplement Science · Last reviewed April 2026

The Supplement Guide — separating the signal from the marketing noise.

The supplement industry is a multibillion-dollar machine. While 90% of products are expensive placebos, a handful of compounds have decades of rigorous evidence supporting their efficacy. This guide focuses strictly on that 10%.

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1. The regulation problem you should know about

In the United States, the 1994 Dietary Supplement Health and Education Act (DSHEA) treats supplements more like food than drugs. The FDA does not approve, test, or verify supplements before they reach shelves. Manufacturers are responsible for their own safety claims; the FDA only intervenes after harm is reported FDA DSHEA. Canada's Natural Health Products regulations are stronger but still permit products to market without robust efficacy proof.

The result, demonstrated repeatedly: a 2008 study testing 634 commercial supplements from 13 countries found 14.8% contained banned substances not listed on the label — most often anabolic steroids or stimulants Geyer 2008. Athletes have been suspended over contaminated, "all-natural" products that delivered substances they never knew they were ingesting.

"There is no rational basis for the use of nutritional supplements by recreational athletes who eat a varied diet. The exceptions — creatine, caffeine, beta-alanine, nitrate, and bicarbonate for elite performance — are short, well-defined, and based on robust evidence. Everything else is a marketing exercise."
Prof. Ronald Maughan — Chair, IOC Consensus on Dietary Supplements; Loughborough University

2. How to read the evidence

This guide grades each supplement using a tier system based on the IOC Consensus Statement on Dietary Supplements (Maughan et al., 2018) and the Australian Institute of Sport's ABCD framework Maughan 2018 (IOC) AIS 2024.

TierMeaningWhat that looks like
Tier AStrong evidence in well-designed studiesMultiple meta-analyses, IOC/ISSN endorsement, replicable performance gains
Tier BPromising, conditional, or population-specificHelps in specific contexts (e.g., deficiency, sport-specific)
Tier CWeak or mixed evidenceMechanism plausible, outcome data thin
Tier DNo good evidence, or banned/unsafeMarketing-driven, contaminated risk, or actively harmful

3. Tier A — supplements that actually work

Creatine monohydrate

The most-studied performance supplement in history — over 1,000 trials. The 2017 ISSN Position Stand concludes it is "safe and effective for increasing high-intensity exercise capacity and lean body mass" Kreider 2017. New 2020s research extends benefits into cognition, particularly under sleep deprivation, and into older adults for sarcopenia prevention.

  • Dose: 3–5 g/day, every day, any time. No "loading" needed unless rapid onset is desired.
  • Form: Creatine monohydrate. Don't pay extra for "HCL," "ethyl ester," or "buffered" — no clinical superiority.
  • Safety: Decades of research; no kidney damage in healthy individuals. Discuss with doctor if you have kidney disease.

Caffeine

A 2020 BJSM umbrella review of 21 meta-analyses concluded caffeine reliably improves endurance, strength, power, and reaction time across virtually every sport tested Grgic 2020.

  • Dose: 3–6 mg/kg, 30–60 min before training. (~210–420 mg for a 70 kg adult.)
  • Watch: Sleep impact (5–7 hr half-life), individual sensitivity, anxiety, and rebound fatigue. Avoid after early afternoon.

Whey, casein, and high-quality protein powders

Not magic — just convenient. If you're hitting the protein targets in our nutrition guide with food alone, you don't need it. If you're not, a scoop is the easiest fix in fitness Morton 2018.

Beta-alanine

Buffers muscle acidity during high-intensity efforts of 1–4 minutes. The ISSN concluded it "improves exercise performance" with the strongest effect in 60-second-to-4-minute efforts Trexler 2015.

  • Dose: 4–6 g/day, split into 2–4 servings to minimise paresthesia ("tingling").
  • Effect window: Builds over weeks; benefits plateau around 4–6 weeks.

Dietary nitrate (beetroot juice)

Multiple trials and meta-analyses show modest endurance benefits — particularly in submaximal efforts up to ~30 min Domínguez 2017. Most of the data comes from concentrated beetroot juice "shots."

4. Tier B — promising for specific situations

Sodium bicarbonate

An ergogenic aid for short-burst performances (~1–7 minutes). Effects are real but gut tolerance is the limiter — many users get GI distress that wipes out the benefit. Buffered or split-dose protocols are evolving the protocol Hadzic 2019.

Collagen + Vitamin C (for tendon and joint pain)

Emerging evidence suggests 15 g of collagen with vitamin C, 30–60 min before mechanical loading, can improve tendon collagen synthesis Shaw 2017. Modest effect sizes; useful for those rehabbing tendinopathies.

Melatonin (for jet lag & sleep onset)

Effective for short-term sleep onset and jet lag, particularly in low doses (0.3–1 mg). Higher doses are not better and may impair next-day alertness Costello 2014.

5. Vitamins & minerals worth checking

Some micronutrient deficiencies are common in northern populations and can quietly degrade health and performance. These are worth checking through bloodwork — not guessing at:

NutrientWhy it mattersDose if deficient
Vitamin D₃Wide deficiency in Canadians, particularly Oct–Apr. Linked to bone, immune, and mood outcomes Holick 2007.1000–2000 IU/day, individualised by serum level
IronCommon deficiency in menstruating women, vegetarians, endurance athletes. Causes fatigue and reduced VO₂max.Per physician based on ferritin/CBC
Vitamin B₁₂Deficiency common in vegans, older adults, and those on metformin or PPIs.500–1000 mcg/day if deficient
MagnesiumMarginal intake common; involved in 300+ enzymatic processes.200–400 mg/day, glycinate or citrate forms
Omega-3 (EPA+DHA)Modest cardiovascular and anti-inflammatory benefit Aung 2018.1–3 g/day combined EPA + DHA

Test, don't guess. Megadoses of fat-soluble vitamins (A, D, E, K) can be toxic. Iron supplementation without lab confirmation is potentially dangerous (haemochromatosis).

6. Tier C — weak or mixed evidence

These have plausible mechanisms but the human-outcome data is thin. They might work for you or might not.

  • BCAAs (branched-chain amino acids) — largely redundant if total daily protein is adequate. The 2017 ISSN review concluded they don't outperform whole protein Wolfe 2017.
  • Glutamine — useful in clinical settings (burn recovery, gut illness); negligible benefit for healthy active adults.
  • HMB (β-hydroxy β-methylbutyrate) — possibly helpful in untrained beginners or older adults; minimal effect in trained athletes.
  • Probiotics — strain-specific; some show benefit for gut health and immune function but the supplement aisle's "general probiotic" claims are largely unsupported.
  • Adaptogens (ashwagandha, rhodiola) — small RCTs show modest stress / cortisol effects; long-term safety data is thin.
  • Pre-workouts — almost all benefit comes from caffeine and creatine. The "proprietary blends" mostly add cost.

7. Tier D — skip these

Categories with consistently poor evidence, frequent contamination findings, or active safety concerns:

  • "Testosterone boosters" — Tribulus, D-aspartic acid, etc. The ISSN reviewed the category and found no convincing evidence for any over-the-counter testosterone-raising supplement in healthy men Antonio 2018.
  • "Fat burners" — most are caffeine + ineffective ingredients. Some have caused liver injury (e.g., ephedra, OxyElite Pro). Save your money and your liver.
  • "Detox" or "cleanse" products — your liver and kidneys do this 24/7. No commercial cleanse has demonstrated outcome benefit in clinical trials Klein 2015.
  • SARMs and prohormones — illegal/unapproved in most jurisdictions, often contaminated, with documented cases of liver damage and cardiovascular events.
  • "Greens powders" — vegetables in powder form at 5× the price. Eat the vegetables.
  • Anything claiming "burn fat while you sleep" or "build muscle without working out" — by definition, marketing.

8. Third-party testing — buy safely or don't bother

If you take a supplement at all, choose products that have been independently verified by a recognised certifier. The three credible options:

Trusted certifications

  • NSF Certified for Sport — tests for over 280 banned substances; widely used by professional sports leagues.
  • Informed Sport / Informed Choice — UK-based; batch-tests every lot.
  • USP Verified — verifies identity, purity, and label accuracy.

If a product doesn't carry one of these marks, you have no real assurance that what's in the bottle matches the label. For competitive athletes subject to drug testing, certification isn't optional — it's the only safe way to supplement.

9. Interactions & contraindications

"Natural" doesn't mean "safe with your medication." Some common interactions:

Talk to your pharmacist or doctor first if you

  • Take blood thinners — vitamin E, fish oil, ginkgo, garlic supplements all affect clotting.
  • Take blood-pressure or heart-rhythm medication — caffeine, ephedra, beta-alanine, licorice all interact.
  • Take antidepressants — St. John's Wort, 5-HTP, and SAMe can cause serotonin syndrome with SSRIs.
  • Take diabetes medication — chromium, berberine, and bitter melon can drop blood sugar dangerously.
  • Are pregnant or breastfeeding — most supplements lack adequate safety data; default to "no" unless your obstetrician approves.
  • Have liver or kidney disease — most supplements are processed there; many can cause harm at therapeutic doses.

Always tell your prescriber what supplements you're taking. They can't keep you safe from things they don't know about.

10. A priority list, not a shopping list

If you took our advice and skipped 90% of the supplement aisle, here's the realistic priority order for most active Beachside members:

  1. Real food first. No supplement has ever out-performed a well-built diet in long-term outcomes.
  2. Get bloodwork. Identify actual deficiencies (vitamin D, iron, B₁₂) instead of guessing.
  3. Add creatine. Cheap, safe, evidence-rich, broadly beneficial.
  4. Use caffeine smartly. Pre-workout timing; protect your sleep.
  5. A protein powder, if useful. A tool for hitting a protein target, not a magic bullet.
  6. Vitamin D₃ in winter if your levels are low (we live at 44°N — most Ontarians are).
  7. Omega-3s if you don't eat fatty fish 2× per week.
  8. Beta-alanine, nitrate, bicarbonate only if you're chasing ergogenic effects in specific competition formats.

That's the entire list for 95% of healthy active adults. Anything beyond it should be selected for a specific reason, in consultation with someone who can read both the science and your bloodwork.

Keep learning

References

Maughan 2018Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439-455.
AIS 2024Australian Institute of Sport. AIS Sports Supplement Framework — ABCD Classification System. ais.gov.au, updated 2024.
FDA DSHEAU.S. Food & Drug Administration. Dietary Supplements: Background Information. fda.gov
Geyer 2008Geyer H, Parr MK, Koehler K, et al. Nutritional supplements cross-contaminated and faked with doping substances. J Mass Spectrom. 2008;43(7):892-902.
Kreider 2017Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18.
Grgic 2020Grgic J, Grgic I, Pickering C, et al. Wake up and smell the coffee: caffeine supplementation and exercise performance — an umbrella review of 21 published meta-analyses. Br J Sports Med. 2020;54(11):681-688.
Morton 2018Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384.
Trexler 2015Trexler ET, Smith-Ryan AE, Stout JR, et al. International society of sports nutrition position stand: Beta-Alanine. J Int Soc Sports Nutr. 2015;12:30.
Domínguez 2017Domínguez R, Cuenca E, Maté-Muñoz JL, et al. Effects of beetroot juice supplementation on cardiorespiratory endurance in athletes: a systematic review. Nutrients. 2017;9(1):43.
Hadzic 2019Hadzic M, Eckstein ML, Schugardt M. The impact of sodium bicarbonate on performance in response to exercise duration in athletes: a systematic review. J Sports Sci Med. 2019;18(2):271-281.
Shaw 2017Shaw G, Lee-Barthel A, Ross ML, et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017;105(1):136-143.
Costello 2014Costello RB, Lentino CV, Boyd CC, et al. The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature. Nutr J. 2014;13:106.
Holick 2007Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266-281.
Aung 2018Aung T, Halsey J, Kromhout D, et al. Associations of omega-3 fatty acid supplement use with cardiovascular disease risks. JAMA Cardiol. 2018;3(3):225-234.
Wolfe 2017Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30.
Antonio 2018Antonio J, Peacock CA, Ellerbroek A, et al. The effects of natural testosterone boosters on athletic performance: a critical review. J Int Soc Sports Nutr. 2018; (selected reviews).
Klein 2015Klein AV, Kiat H. Detox diets for toxin elimination and weight management: a critical review of the evidence. J Hum Nutr Diet. 2015;28(6):675-686.