Roll Call

“Aspartic Acid?”Here!

Varies by source

Hasn’t appeared in a scanned product yet.

As a supplement

Talk to your doctor or pharmacist.

Roll Call does not check drug interactions or assess personal safety.

Aspartic acid is a non-essential amino acid the body makes on its own and also obtains from protein-containing foods; it participates in cellular energy pathways and neurotransmitter synthesis.

Why it’s used

Included in some formulas, particularly as its D-isomer form, on claims of supporting testosterone levels or athletic performance; the plain L-form is more often present simply as a building-block amino acid.

What the evidence says

Evidence for D-aspartic acid raising testosterone or improving performance comes from a handful of small studies with mixed and inconsistent results; plain L-aspartic acid has not been studied for these claims at all.

Context

The small trials that exist on D-aspartic acid used it over a few weeks in specific populations such as resistance-trained men, and results have not been consistently replicated.

Rumors

  1. D-aspartic acid supplements boost natural testosterone production.

    Unresolvedhealth and safety evidence

    Measured as a biomarker.

    Who’s saying this

    • 5% Nutrition — a brand: sells sports nutrition supplements and lifestyle apparel
      How we know who this is
      • “Founded in 2014 by Rich Piana, 5% Nutrition continues to develop industry-leading premium quality sports nutrition products while offering a complete line of lifestyle apparel and gear so you can represent how you want, when you want.” (their page)
  2. D-aspartic acid improves strength, lean muscle growth, fat loss, energy and libido.

    Sources cited — check not cleared.

    Studied in: resistance-trained men aged 18-36.

    Measured as an outcome.

    Who’s saying this

    • ALLMAX Nutrition — a brand: sells sports supplements
      How we know who this is
      • “ALLMAX Nutrition manufactures supplements to pharmaceutical-grade quality standards under cGMP-certified conditions.” (their page)
  3. D-aspartic acid increases sperm count and motility in men.

    We haven’t found evidence strong enough to support this or rule it out.

    What was measured is not yet noted.

    Who’s saying this

  4. L-aspartic acid reduces fatigue and improves muscle strength and sports performance.

    Supports — suggestivehealth and safety evidence

    Measured as an outcome.

    Who’s saying this

  5. Taking a lot of L-aspartic acid causes bloating, stomach problems and diarrhea.

    Not gradedhealth and safety evidence

    Sources cited — no verdict reached.

    What was measured is not yet noted.

    Who’s saying this