Quick Comparison
| PEA (Palmitoylethanolamide) | Vitamin D3 | |
|---|---|---|
| Half-Life | 1-2 hours (rapidly metabolized). Micronized forms have improved bioavailability | 15-25 days |
| Typical Dosage | Standard: 300-1200 mg daily in 2-3 divided doses. Start at 600 mg daily. Micronized or ultra-micronized (um-PEA) forms have much better absorption. For chronic pain: 600 mg twice daily. For neuroinflammation: 400-600 mg twice daily. Effects build over 2-4 weeks. | Standard: 2000-5000 IU daily. Optimal blood level: 40-60 ng/mL (100-150 nmol/L). Most adults need 4000-5000 IU to reach optimal levels. Take with fat for absorption. Get blood levels tested before supplementing — both deficiency and excess are harmful. |
| Administration | Oral (capsules, powder). Micronized (m-PEA) or ultra-micronized (um-PEA) forms preferred for bioavailability. | Oral (softgels, drops, tablets). D3 (cholecalciferol) preferred over D2 (ergocalciferol). Take with a fat-containing meal. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
PEA (Palmitoylethanolamide)
PEA activates PPAR-alpha (peroxisome proliferator-activated receptor alpha), a nuclear receptor that heterodimerizes with RXR and downregulates pro-inflammatory gene expression (NF-kB target genes, COX-2, iNOS, TNF-alpha). It has an 'entourage effect' on the endocannabinoid system — it inhibits the degradation of anandamide by fatty acid amide hydrolase (FAAH) through allosteric modulation or substrate competition, and upregulates CB2 receptor expression on immune cells. This provides anti-inflammatory and analgesic effects without directly activating CB1/CB2. PEA also activates GPR55 and GPR119. It inhibits mast cell degranulation (reducing histamine, tryptase, and cytokine release) and reduces microglial activation in the brain (inhibiting Iba1 expression and pro-inflammatory cytokine production). PEA may also modulate TRPV1.
Vitamin D3
Vitamin D (1,25-dihydroxyvitamin D3) crosses the blood-brain barrier and binds to vitamin D receptors (VDR), a nuclear receptor expressed on neurons, astrocytes, microglia, and oligodendrocytes. VDR heterodimerizes with RXR and binds vitamin D response elements (VDREs) to regulate transcription. It upregulates neurotrophic factors: GDNF (glial cell line-derived), NGF, NT-3 via CREB and other transcription factors. Vitamin D promotes serotonin synthesis by upregulating tryptophan hydroxylase 2 (TPH2) and dopamine synthesis via tyrosine hydroxylase. It reduces neuroinflammation by suppressing microglial IL-1beta, TNF-alpha, and iNOS, and supports calcium homeostasis via regulation of L-type voltage-gated calcium channels and calbindin-D28k. Vitamin D regulates over 200 genes including those for neuroprotection, synaptic plasticity, and myelination.
Risks & Safety
PEA (Palmitoylethanolamide)
Common
Very well-tolerated — rare side effects. Mild GI discomfort.
Serious
None documented. Over 30 clinical trials confirm excellent safety profile.
Rare
Skin rash.
Vitamin D3
Common
Generally very safe at standard doses.
Serious
Toxicity at very high doses (>10,000 IU daily for months) — causes hypercalcemia (nausea, kidney stones, cardiac arrhythmia).
Rare
Headache, metallic taste, nausea.
Full Profiles
PEA (Palmitoylethanolamide) →
An endogenous fatty acid amide produced naturally in the body in response to pain and inflammation. PEA activates PPAR-alpha receptors and indirectly enhances endocannabinoid signaling without binding to cannabinoid receptors. It has strong evidence for neuropathic pain, neuroinflammation, and neuroprotection. Unlike anti-inflammatory drugs, it resolves inflammation rather than merely suppressing it.
Vitamin D3 →
Technically a hormone, not a vitamin. Vitamin D3 (cholecalciferol) receptors are found throughout the brain, particularly in the hippocampus and prefrontal cortex. Deficiency — affecting an estimated 40-75% of adults worldwide — is associated with cognitive impairment, depression, and increased Alzheimer's risk. Supplementation is one of the most impactful interventions for people with low levels.