Which Supplements Are Actually Worth It? An Evidence-Based Guide

The supplement industry wants your money. They'll promise muscle, energy, fat loss, and immortality—often without evidence to back it up.

Here's what actually works, what might work, and what's a complete waste of money.

The Honest Truth About Supplements

Supplements Are Supplementary

They're meant to supplement a good diet—not replace it. If your nutrition is poor, supplements won't save you. If your nutrition is solid, most supplements won't add much.

The 90/10 Rule

90% of results come from:

• Training consistently
• Eating enough protein
• Getting adequate sleep
• Managing stress

10% (maybe) comes from supplements. Most people obsess over the 10% while ignoring the 90%.

Most Supplements Don't Work

The industry is largely unregulated. Many products:

• Contain less active ingredient than claimed
• Have no evidence supporting their claims
• Are wildly overpriced for what they provide
• Work in studies but at doses nobody actually takes

Tier 1: Supplements That Actually Work

Creatine Monohydrate

The evidence: Hundreds of studies. One of the most researched supplements. Actually works.

What it does:

• Increases strength and power output
• Improves high-intensity performance
• May help with muscle growth
• Potential cognitive benefits

How to take it:

• 3-5 grams daily
• Timing doesn't matter
• No loading phase necessary
• Monohydrate is the most studied form

Cost: ~$0.10-0.15 per day

Verdict: If you lift weights, creatine is worth taking. It's cheap, safe, and effective.

Protein Powder

The evidence: Well-established. Protein works. Powder is just convenient protein.

What it does:

• Helps you hit protein targets
• Convenient post-workout option
• Cost-effective protein source (often)

What it doesn't do:

• Work magic beyond regular protein
• Provide anything special over food protein

How to take it:

• Only if you need help hitting protein targets
• 20-40g per serving
• Whey, casein, or plant-based all work

Cost: ~$0.50-1.50 per serving

Verdict: Useful tool if you struggle to eat enough protein. Not necessary if you hit targets through food.

Caffeine

The evidence: Extensively studied. Clearly works for performance.

What it does:

• Increases alertness and focus
• Improves endurance performance
• May increase strength output
• Reduces perceived effort

How to take it:

• 3-6 mg per kg bodyweight
• 30-60 minutes before training
• Coffee works just fine
• Don't take late in the day (sleep matters)

Cost: Basically free (coffee)

Verdict: Works, and most people already consume it. Just be strategic about timing.

Vitamin D (If Deficient)

The evidence: Strong, but mainly for those who are deficient.

What it does:

• Essential for bone health
• Supports immune function
• May affect muscle function
• Important for mood

Who needs it:

• People in northern climates
• Those who don't get sun exposure
• Darker-skinned individuals (higher needs)
• People who test low

How to take it:

• Get tested first ideally
• 1,000-5,000 IU daily typical
• Take with fat for absorption

Cost: ~$0.05-0.10 per day

Verdict: Worth taking if you're likely deficient. Get tested if unsure.

Tier 2: Might Work, Depends on Situation

Fish Oil (Omega-3s)

The evidence: Good for general health; fitness benefits less clear.

What it does:

• Supports heart health
• May reduce inflammation
• Possible minor muscle-building benefits

Who needs it:

• People who don't eat fatty fish
• Those with inflammatory issues
• General health insurance

How to take it:

• 2-3g combined EPA/DHA daily
• Quality matters (purity, freshness)

Cost: ~$0.30-0.50 per day for quality

Verdict: Reasonable health supplement. Not a game-changer for fitness specifically.

Magnesium

The evidence: Important mineral; many people are insufficient.

What it does:

• Supports muscle and nerve function
• May improve sleep
• Important for hundreds of bodily processes

Who needs it:

• Athletes (lose through sweat)
• Those with poor dietary intake
• People with sleep issues

How to take it:

• 200-400mg daily
• Glycinate or citrate forms absorb well

Cost: ~$0.10-0.20 per day

Verdict: Worth considering, especially for sleep. Get from diet first if possible.

Beta-Alanine

The evidence: Decent for specific applications.

What it does:

• Buffers lactic acid
• May improve performance in 1-4 minute efforts
• The tingling is harmless

Who needs it:

• Athletes doing high-rep, high-intensity work
• CrossFit, rowing, middle-distance running

How to take it:

• 3-6g daily (can split doses to reduce tingling)
• Takes weeks to saturate

Cost: ~$0.15-0.25 per day

Verdict: Useful for specific activities. Not necessary for most people.

Citrulline

The evidence: Modest but real effects on performance.

What it does:

• Increases blood flow
• May reduce fatigue
• Possible strength/rep improvements

How to take it:

• 6-8g citrulline malate pre-workout
• Or 3-4g L-citrulline

Cost: ~$0.20-0.40 per serving

Verdict: Minor benefits. Fine in a pre-workout but not essential.

Tier 3: Probably Doesn't Work (Or Not Worth It)

BCAAs

The evidence: Largely debunked for most uses.

The problem:

• If you eat enough protein, you already get plenty of BCAAs
• Only useful in very specific scenarios (fasted training, maybe)
• Complete protein is more effective

Verdict: Waste of money for most people. Eat protein instead.

Testosterone Boosters

The evidence: Almost universally ineffective.

The reality:

• No supplement meaningfully raises testosterone in healthy people
• The ones that "work" have effects too small to matter
• Sleep, stress management, and body fat % matter more

Verdict: Save your money. None of them work.

Fat Burners

The evidence: The only "effective" ingredients are just caffeine.

The reality:

• Expensive caffeine pills with scary-sounding ingredients
• No supplement burns significant fat
• Calorie deficit is the only way

Verdict: Total waste of money. Drink coffee.

Most Pre-Workout Supplements

The evidence: Overpriced combinations of a few things that work.

The reality:

• Effective ingredients: caffeine, citrulline, beta-alanine, creatine
• Everything else is likely ineffective or underdosed
• You can buy these separately for less

Verdict: If you like the convenience, fine. But you're overpaying for caffeine plus marketing.

Glutamine

The evidence: Not supported for healthy, well-fed individuals.

Who it might help:

• Hospital patients
• People with gut issues
• Perhaps extreme endurance athletes

Verdict: Not worth it for regular gym-goers.

Mass Gainers

The evidence: They're just protein powder + sugar + calories.

The problem:

• Extremely expensive per calorie
• You can eat food for cheaper
• Often low-quality ingredients

Verdict: Make your own shakes. It's cheaper and healthier.

Supplement Red Flags

Signs of a Scam

Proprietary blends: "Our special blend of..." = We won't tell you how much of each ingredient.

Before/after photos: Easily manipulated. Prove nothing.

Endorsements from huge athletes: They didn't get that way from supplements. Many are enhanced.

"Clinically proven": Often in unrealistic doses, not the dose in the product, or in non-relevant populations.

Extreme claims: "Gain 20 lbs of muscle in a month" = They're lying to you.

Questions to Ask

1. Is there independent research on this ingredient?
2. Is the studied dose the same as in this product?
3. Is the effect size meaningful or trivial?
4. Is it worth the cost compared to food?
5. Do I have the basics covered first?

How to Save Money on Supplements

Buy What You Need, Not a Stack

You probably only need:

• Creatine (if you lift)
• Protein powder (if you need it for targets)
• Vitamin D (if deficient)
• Maybe fish oil

That's it for most people.

Buy Generic/Basic Forms

• Creatine monohydrate (not fancy forms)
• Basic whey concentrate (not expensive isolates)
• Store-brand vitamins

Buy in Bulk

Larger containers = lower per-serving cost.

Skip the Marketing

Fancy labels and influencer endorsements cost money. You pay for them.

The Priority List

Before any supplement, ask:

1. Am I training consistently?
2. Am I eating enough protein from food?
3. Am I sleeping 7-9 hours?
4. Am I managing stress?
5. Am I eating vegetables and varied foods?

If any answer is "no," fix that before buying supplements.

The Bottom Line

Worth it for most people:

• Creatine monohydrate (~$4/month)
• Protein powder (if needed for targets)
• Vitamin D (if deficient)

Worth considering:

• Fish oil (if low fish intake)
• Magnesium (if sleep issues or heavy sweating)
• Caffeine (just drink coffee)

Not worth it for most:

• BCAAs
• Testosterone boosters
• Fat burners
• Most pre-workouts
• Glutamine
• Mass gainers
• Most things with aggressive marketing

Total essential supplement cost: ~$15-30/month

Save the rest. Spend it on quality food instead. Your nutrition and training matter infinitely more than any pill or powder.

Supplements are the 1% that gets 90% of the marketing budget. Don't fall for it. Master the basics, then decide if the marginal gains from supplements are worth your money.

For most people, they're not.