Phosphatidic Acid
Also known as: PA, Phosphatidic acid, PAS (when combined with phosphatidylserine)
Randomised controlled trials show that PA-containing supplements can blunt HPA-axis responses to acute stress and may reduce some premenstrual symptoms when given as a PAS complex (400 mg PA + 400 mg PS). Evidence for PA improving muscle size or strength is mixed: one small RCT of PA alone (750 mg/day) found no benefit over placebo, while an 8-week trial of a multi-ingredient product containing PA reported greater gains in lean body mass and strength versus placebo — attribution to PA alone cannot be made from that study.
Last reviewed: 2026-10-14 · 5 indexed studies
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Overview
Phosphatidic acid (PA) is a phospholipid signalling molecule studied for effects on muscle anabolism and stress-axis regulation. Human trials have tested PA alone and as part of a phosphatidylserine+phosphatidic acid complex (PAS) or multi-ingredient products, with mixed results for muscle outcomes and more consistent effects on cortisol/stress measures in chronically stressed subjects.
Mechanism & Function
Mechanism of Action
PA is a lipid messenger implicated in activation of the mammalian target of rapamycin (mTOR) pathway, which can stimulate muscle protein synthesis. When given as a PAS complex, clinical studies also report modulation of hypothalamic–pituitary–adrenal (HPA) axis responses, reducing ACTH and cortisol responses to stressors.
Physiological Role
Signal transduction via mTOR activation; modulation of HPA-axis (ACTH/cortisol) responses under acute psychosocial challenge.
Primary Pathways
Performance / Health Relevance
Mechanistically plausible for promoting muscle protein synthesis through mTOR signalling, but human efficacy for strength or hypertrophy is inconsistent. More consistent clinical effects are seen for dampening ACTH/cortisol responses to acute stress when PA is provided with phosphatidylserine (PAS).
Evidence Review
No meta-analyses or systematic reviews indexed for this ingredient yet.
Dimensions marked N/A have no indexed evidence of that class. They are shown as unavailable rather than scored.
Practical Use & Dosage
- Minimum Effective Dose
- Not established for isolated PA; studies used 750 mg/day of PA alone and PAS formulations containing 400 mg PA + 400 mg phosphatidylserine.
- Optimal Range
- Not established.
- Upper / Caution Level
- Not established.
- Timing
- Not established.
- Best Format
- Oral capsule/softgel as used in trials; can be provided alone or in combination with phosphatidylserine or other anabolic agents.
- Bioavailability
- Human trials used oral formulations; specific bioavailability data not provided in the cited abstracts.
- Absorption Considerations
- Not specified in the provided clinical abstracts.
Safety & Interactions
Side Effects
- •No consistent adverse events reported in the provided trials; overall well tolerated in short-term studies
Contraindications
- Not established from available abstracts
Drug Interactions
- •Not established from available abstracts
Who Should Avoid
- •Pregnant or breastfeeding women: insufficient data
- •People with serious medical conditions: consult a clinician
Monitoring
No specific monitoring reported in the cited trials; monitor general tolerability and seek medical advice if unusual symptoms occur.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Phosphatidic Acid typically used or indicated?
Phosphatidic Acid is most commonly used for: Strength and muscle mass support (ergogenic), Stress modulation / HPA-axis normalisation, Premenstrual symptom relief (when combined with phosphatidylserine). Signal transduction via mTOR activation; modulation of HPA-axis (ACTH/cortisol) responses under acute psychosocial challenge.
How does Phosphatidic Acid work?
PA is a lipid messenger implicated in activation of the mammalian target of rapamycin (mTOR) pathway, which can stimulate muscle protein synthesis. When given as a PAS complex, clinical studies also report modulation of hypothalamic–pituitary–adrenal (HPA) axis responses, reducing ACTH and cortisol responses to stressors.
What is the recommended dose of Phosphatidic Acid?
The optimal range is Not established.. with a minimum effective dose of Not established for isolated PA; studies used 750 mg/day of PA alone and PAS formulations containing 400 mg PA + 400 mg phosphatidylserine.. Best taken: Not established.. Upper / caution level: Not established..
What are the side effects of Phosphatidic Acid?
Reported side effects include: No consistent adverse events reported in the provided trials; overall well tolerated in short-term studies. Monitoring: No specific monitoring reported in the cited trials; monitor general tolerability and seek medical advice if unusual symptoms occur.
Does Phosphatidic Acid interact with medications?
Known or theoretical interactions: Not established from available abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid Phosphatidic Acid?
Phosphatidic Acid is generally not recommended for: Pregnant or breastfeeding women: insufficient data; People with serious medical conditions: consult a clinician; and Not established from available abstracts.
How strong is the evidence for Phosphatidic Acid?
Evidence level: Moderate (overall score 69/100), based on 5 indexed studies on SuppIndex.
Research & References (5)
Effects of phosphatidic acid supplementation on muscle thickness and strength in resistance-trained men.
Randomised trial in resistance-trained men comparing 750 mg/day phosphatidic acid to placebo during an 8-week supervised resistance-training programme.
The effects of phosphatidic acid supplementation on strength, body composition, muscular endurance, power, agility, and vertical jump in resistance trained men.
Double-blind RCT testing MaxxTOR®, a multi-ingredient product whose main active is reported as PA but which also contained leucine, HMB and vitamin D3, versus placebo in resistance-trained men over 8 weeks.
A lecithin phosphatidylserine and phosphatidic acid complex (PAS) reduces symptoms of the premenstrual syndrome (PMS): Results of a randomized, placebo-controlled, double-blind clinical trial.
Randomised, double-blind placebo-controlled trial of a soy lecithin phosphatidylserine+phosphatidic acid complex (PAS: 400 mg PS + 400 mg PA) versus placebo in women with premenstrual syndrome over three treatment cycles.
A soy-based phosphatidylserine/ phosphatidic acid complex (PAS) normalizes the stress reactivity of hypothalamus-pituitary-adrenal-axis in chronically stressed male subjects: a randomized, placebo-controlled study.
Randomised, placebo-controlled study in healthy males comparing two doses of a PAS complex (200 mg PS + 200 mg PA or 400 mg PS + 400 mg PA) versus placebo over 42 days, followed by the Trier Social Stress Test (TSST).
Effects of soy lecithin phosphatidic acid and phosphatidylserine complex (PAS) on the endocrine and psychological responses to mental stress.
Placebo-controlled trial testing 400, 600, and 800 mg/day of a soy lecithin phosphatidic acid+phosphatidylserine complex (PAS) versus placebo for three weeks, followed by the TSST.
Related Ingredients
Other top-rated ingredients in Ergogenic Compounds.
Creatine Monohydrate
94/100A naturally occurring nitrogenous organic acid that facilitates recycling of adenosine triphosphate (ATP) in muscle and brain tissue via the phosphocreatine shuttle.
Maltodextrin
78/100Short-chain α-1,4 linked glucose polymer that is rapidly hydrolysed by brush-border maltase to glucose; near-equivalent glycaemic response to glucose but lower osmolality at concentration.
Cyclic Dextrin (HBCD)
72/100Produced via cyclic-glucanotransferase action on amylopectin, HBCD forms cluster-like macromolecules ~160 kDa that solubilise at low osmolality (≈4 mOsm/L) and clear the stomach faster than maltodextrin or glucose polymers.
Research Overview
Moderate EvidenceCite this ingredient
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Stable URL
https://thesuppindex.com/ingredients/phosphatidic-acid
SuppIndex. (2026). Phosphatidic Acid: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/phosphatidic-acid
Based on 5 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
PA is often studied combined with phosphatidylserine or with anabolic adjuncts (leucine, HMB, vitamin D). Efficacy seen in multi-ingredient products cannot be attributed to PA alone.