Most supplements are useless
The supplement industry runs on hope and weak studies. Of the thousands of products sold, a small handful have strong evidence. Recommend those; everything else is optional.
The tier-1 list (strong evidence)
Creatine monohydrate — the most-researched supplement in sports nutrition. Increases strength, power, lean mass. Safe long-term. 3-5g/day, any time. ~$15 for months of supply. Caffeine — improves perceived effort, performance, alertness. 100-300mg pre-workout. Reduce or cycle if tolerance builds. Protein powder (whey, casein, plant) — not a "supplement" so much as a convenient food. Use to hit daily protein targets when whole-food protein isn't practical. Vitamin D — supplement if blood test confirms deficiency. 2,000-4,000 IU/day for most adults. Omega-3 (EPA/DHA from fish oil or algae) — anti-inflammatory, heart and brain health. 1-3g EPA/DHA combined daily. Skip if eating fatty fish 2-3×/week. Magnesium — common deficit, supports sleep, muscle relaxation. 200-400mg/day, evening. Glycinate or citrate forms preferred.The tier-2 list (some evidence, situational)
Beta-alanine — improves performance in 60-240 second efforts. 3-6g/day. Causes harmless tingling. Mostly useful for HIIT, CrossFit, sprints in the 1-4 min range. Citrulline malate — small performance boost. 6-8g pre-workout. Multivitamin — insurance against gaps in diet. Modest effect for most adults. Helpful for picky eaters. Probiotics — gut health support. Some clinical evidence for specific strains. Expensive; food sources (yogurt, kefir, fermented foods) usually adequate.The tier-3 list (overhyped, weak evidence)
- Pre-workout proprietary blends (mostly caffeine + creatine in a fancy package)
- Most fat burners (some caffeine-driven, modest effect, side effects)
- Testosterone boosters (placebo unless prescription)
- "Detox" or "cleanse" products (no scientific basis)
- BCAAs (redundant if total protein is adequate)
- Glutamine (no benefit for non-clinical populations)
What to tell clients
Most clients waste money on supplements. Order of priority:
1. Get nutrition basics right (calories, protein, vegetables) 2. Sleep 7+ hours 3. Train consistently 4. Then consider creatine, vitamin D (if deficient), omega-3, magnesium
Adding supplements before nailing basics is putting paint on a broken car.
Quality and safety
The FDA doesn't pre-approve supplements. Products can be adulterated, mislabeled, or dangerous. Recommend:
- USP-verified or NSF-certified products
- Reputable brands (Thorne, NOW, Pure Encapsulations, Optimum Nutrition)
- Single-ingredient products over proprietary blends
Trainer scope of practice on supplements
You can recommend tier-1 supplements (creatine, protein) without overstepping. You can NOT prescribe anything therapeutic (thyroid support, hormone support, anything addressing a medical condition). Refer those to a physician or registered dietitian.
TL;DR
Tier 1 (strong evidence): creatine, caffeine, protein, vitamin D, omega-3, magnesium. Tier 2: beta-alanine, citrulline, multivitamin. Most products are tier 3 (overhyped). Nutrition basics first, supplements after. Recommend third-party tested products.