Supplements: an honest guide

The supplement aisle has an answer for male fertility anxiety, and it costs about forty pounds a month. Before you subscribe, here is what the evidence actually says - including the places where the honest summary is save your money.

The headline

Dozens of small trials have tested antioxidants and micronutrients against semen parameters, and many report improvements - a bit more motility here, better concentration there. But when the rigorous reviews pool those trials, the certainty collapses: studies are small, short, inconsistently designed, and very few measure the outcome that matters - actual pregnancies and births. The largest high-quality trials of antioxidant blends found no improvement in live birth rates. That's the honest baseline: promising signals, weak proof.

Down the list

• CoQ10 - the most consistent parameter signal in the pile, mostly for motility, at meaningful doses. If you try one supplement, this is the defensible pick. Proof it makes babies: still missing.
• Zinc and selenium - essential to sperm production, and worth having enough of. Correcting a deficiency helps; mega-dosing on top of a normal diet has no good evidence and zinc in excess causes its own problems.
• Vitamin D - worth testing and correcting if you're deficient (many men are). Evidence for supplementing beyond that: thin.
• Omega-3 / fish oil - some observational and trial signal on parameters. Eating actual fish carries the same signal with better evidence - see Eat like it matters.
• Folate, L-carnitine, vitamins C and E - individually modest, mixed results; most positive findings come from small studies that haven't replicated well.

The red flags

• "Testosterone booster" marketing. Nothing sold over the counter meaningfully raises testosterone - and actual testosterone (TRT, steroids) shuts down sperm production. Any fertility product wearing muscle-market branding misunderstands the biology it's selling to. See Training, testosterone and the steroid trap.
• Proprietary blends - undisclosed doses in a trademarked mix mean you cannot compare against any study. That's the point of them.
• Anything promising percentages - "improves count by 74%!" cites either nothing or one tiny study.

The uncomfortable comparison

Every lever with strong evidence is free: not smoking, drinking less, keeping weight in range, staying cool, sleeping. A forty-pound tub is more appealing than any of those precisely because swallowing a capsule is easier than changing a habit. The industry knows it. Now you do too.

If your diet is genuinely poor, money goes further at the grocery store than the supplement shop. If you do supplement: pick one thing, at a studied dose, give it a full three-month production cycle, and let a semen analysis - not the label - tell you if it did anything.