The supplement industry generates billions per year — and a significant portion of that money is spent on products that don’t do what they promise. Flashy packaging, sponsored influencers, and promises of quick results sell extremely well. But what does science actually validate?
Let’s analyze the most popular supplements and separate what works from what’s, at best, unnecessary.
The ones that work (strong evidence)
Creatine
Verdict: works. One of the most studied supplements in history.
Creatine is naturally produced by your body and found in meat and fish. Supplementation increases phosphocreatine stores in muscles, improving performance in high-intensity, short-duration exercises.
What science shows:
- Improves strength and power — consistent effect across hundreds of studies
- May increase muscle mass — indirectly, by allowing you to train harder
- Safe for long-term use — doesn’t cause kidney damage in healthy people (common myth)
- May have cognitive benefits — preliminary research suggests improvements in memory and reasoning
Dose: 3-5 g per day of creatine monohydrate. No loading phase needed. The cheapest form (monohydrate) is the most studied and effective.
Value: excellent. One of the cheapest and most effective supplements available.
Creatine isn’t “just for bodybuilders.” Studies show benefits for older adults, vegetarians, and even cognitive health.
Whey Protein
Verdict: works, but it’s not magic.
Whey protein is simply powdered protein extracted from milk. It’s not a steroid, not a drug — it’s food in concentrated form.
When it’s worth it:
- If you can’t hit your protein target with food (1.6-2.0 g/kg for active people)
- As a convenient option post-workout or for snacks
- For vegetarians struggling to get enough protein
When it’s NOT worth it:
- If you already eat enough protein from food — your body doesn’t use the excess
- As a substitute for complete meals — it lacks fiber, micronutrients, and satiety
Dose: 20-40 g per serving, 1-2 times daily as needed.
Vitamin D
Verdict: works for those who are deficient — and many people are.
Vitamin D is produced by your skin with sun exposure. But in practice, a large portion of the population has insufficient levels — especially those who work indoors, use a lot of sunscreen, or live in low-sunlight regions.
What science shows:
- Essential for bone health (calcium absorption)
- Important role in the immune system
- Deficiency linked to fatigue, muscle weakness, and low mood
Recommendation: Get a blood test to check your levels before supplementing. If below 30 ng/mL, supplementation is recommended — talk to a healthcare professional about dosage.
Caffeine
Verdict: works as an ergogenic aid (improves performance).
Caffeine is the most widely used ergogenic supplement in the world. And for good reason — it works.
What science shows:
- Improves performance in endurance and strength exercises
- Increases focus and alertness — effect on the central nervous system
- May help with fat burning — modest but real effect
Dose: 3-6 mg per kg body weight, 30-60 minutes before training. A strong cup of coffee has ~80-100 mg.
Note: Tolerance builds over time. Use strategically, not every day.
The questionable ones (weak or mixed evidence)
BCAAs (branched-chain amino acids)
Verdict: probably unnecessary if you already eat enough protein.
BCAAs (leucine, isoleucine, valine) are essential amino acids present in any protein source. Isolated supplementation became a craze, but science is clear:
- If you consume adequate protein (1.6+ g/kg/day), extra BCAAs provide no additional benefits
- They’re already present in whey, chicken, eggs, meat, fish
- Recent studies show no advantage in recovery or muscle gain when total protein is adequate
When it might make sense: Training in a prolonged fasted state or for someone consuming very little total protein. For most people, it’s money wasted.
Collagen
Verdict: weak evidence for most promised benefits.
Collagen has become a marketing darling — promising youthful skin, healthy joints, and shiny hair.
What science shows:
- For skin: some studies show modest improvements in elasticity and hydration, but evidence quality is low
- For joints: research with type II collagen shows mixed results for joint pain
- The fundamental problem: ingested collagen is digested like any protein — your body doesn’t direct the amino acids specifically to skin or joints
If you want to try: 10-15 g per day for at least 8-12 weeks. But don’t expect miracles.
Multivitamins
Verdict: probably unnecessary if your diet is varied.
The multivitamin industry sells the idea of “nutritional insurance.” But large-scale studies haven’t found significant benefits:
- A 2022 review in JAMA concluded that multivitamins don’t prevent cardiovascular disease or cancer in healthy people
- If you eat fruits, vegetables, proteins, and varied grains, you’re likely already getting what you need
When it makes sense: Older adults, pregnant women, people with severe dietary restrictions or diagnosed deficiencies. Always with professional guidance.
The ones that don’t work (or don’t justify the price)
Fat burners / thermogenics
Most thermogenics are repackaged caffeine at an inflated price. The active ingredient that works (caffeine) costs pennies. The rest — green tea extract, capsaicin, carnitine — has negligible effects on fat burning.
Alternative: black coffee. Same effect, much cheaper.
Glutamine (for performance)
Frequently sold for muscle recovery and immunity. But in healthy people who eat well, glutamine supplementation doesn’t improve performance or recovery.
It may have utility in clinical settings (burn patients, ICU), but not for gym-goers.
”Natural testosterone boosters” / Tribulus / ZMA
Supplements promising to naturally boost testosterone — tribulus terrestris, D-aspartic acid, ZMA — don’t work in healthy people with normal hormone levels. Controlled studies show no significant effect.
How to decide if a supplement is worth it
Before buying any supplement, ask these questions:
- Does my diet already cover this need? — If yes, it’s probably unnecessary
- Is there strong evidence in humans? — Not in animals, not in test tubes — in humans
- Was the study done on people like me? — Results in elite athletes don’t always apply to someone training 3x per week
- Who’s recommending it? — A healthcare professional or a sponsored influencer?
- Does the cost justify it? — Creatine at $15/month vs collagen at $40/month with weak evidence
Quick summary
| Supplement | Works? | For whom |
|---|---|---|
| Creatine | ✅ Yes | Strength/power training |
| Whey Protein | ✅ Yes | Anyone not hitting protein via diet |
| Vitamin D | ✅ Yes | Those with confirmed deficiency |
| Caffeine | ✅ Yes | Pre-workout (strategic use) |
| BCAAs | ⚠️ Questionable | Only if total protein is insufficient |
| Collagen | ⚠️ Questionable | Weak evidence, low expectations |
| Multivitamin | ⚠️ Questionable | Only with dietary restrictions or deficiency |
| Fat burners | ❌ No | Repackaged caffeine at inflated price |
| Glutamine | ❌ No | No benefit for healthy people |
| ”Natural test boosters” | ❌ No | Don’t work at normal hormone levels |
Conclusion
Most people don’t need supplements — they need better food. Creatine and protein powder are among the few with strong evidence and real value. The rest, in most cases, is sophisticated marketing selling results that food and training already deliver.
Before spending on supplements, invest in real food. And if you do choose to supplement, choose based on evidence — not packaging.