Inhibition of PDE5 results in: increased intracellular cGMP concentrations and prolonged nitric oxide (NO) signaling,

The NO–cGMP pathway plays a central role in synaptic plasticity. This pathway regulates: long-term potentiation (LTP), synaptic transmission, learning, memory formation, neuronal survival. Numerous studies demonstrate significant enhancement of hippocampal LTP following sildenafil administration.

Enhancement of Synaptic Plasticity Long-term potentiation is widely regarded as the cellular basis of learning and memory. Experimental models consistently show that sildenafil: increases LTP magnitude, prolongs LTP duration, improves spatial learning, enhances memory consolidation. Most of these effects are observed within the hippocampus, the principal brain region responsible for episodic memory.

Upregulation of Neurotrophic Factors One of the most reproducible findings is increased expression of brain-derived neurotrophic factor (BDNF). BDNF promotes: neuronal survival, dendritic growth, synapse formation, adult neurogenesis, long-term synaptic remodeling.

Promotion of Adult Neurogenesis Studies indicate that sildenafil stimulates neuronal proliferation within: the dentate gyrus, the subventricular zone. Enhanced neurogenesis has been associated with improved cognitive recovery following stroke and traumatic brain injury.

Reduction of Neuroinflammation Neuroinflammation is recognized as a major contributor to Alzheimer's disease, Parkinson's disease, vascular dementia, and normal brain aging. PDE5 inhibitors appear to suppress activation of: microglia, astrocytes.Experimental studies report reduced production of inflammatory mediators including: TNF-α, IL-1β, IL-6, NF-κB signaling. These anti-inflammatory effects likely contribute substantially to their neuroprotective profile.

Protection Against Oxidative Stress Several studies demonstrate that PDE5 inhibition: decreases reactive oxygen species (ROS), improves mitochondrial function, preserves ATP production, reduces neuronal apoptosis. Mitochondrial preservation may represent another important mechanism contributing to long-term neuronal survival. https://viagrala.com/

- Baseline from age and gender alone: 83 years. Where their current habits point: 97. Fully optimized: 101.

- So the median respondent has already banked ~14 years through habits, with only ~3.6 left to claim. Most of the available gain is behind them, not ahead.

- Walking is the single biggest untapped lever by a wide margin, ahead of aerobic exercise and strength training. Only 13% are hitting the step target.

- Untapped potential runs ~5 years for the under-40s and ~3 for everyone over 40. Share of potential already captured peaks in the 50s, then slides.

- The drop after 80 is almost entirely exercise falling away. After 90, daily steps collapse from 8,000 to 2,000.

- Diet gaps cluster in the same places: nuts/olive oil, fish, legumes, whole grains. Red meat, processed meat and sugary drinks are already largely avoided.

- Demographics: 62% female, median age 57. Self-selected and older than the general population, so read the absolute lifespan numbers with that in mind.

Full breakdown with the age-group charts and a profile of the archetypal respondent:

https://www.unaging.com/aging/10000-people-have-used-the-true-age-calculator/

• Multivitamins and specific vitamins (D, C, E): Randomized controlled tests (RCTs) have shown no benefit
• Fish oil: RCTs haven't worked out, and dementia studies showed a trend toward increasing (!?) dementia
• Resveratrol and NMN: Sinclair’s attempts to do CR in a pill. Both failed.
• Rapamycin: RCTs failed to meet their target endpoints
• Metformin: superb for diabetics, not helpful for lifespan
• Aspirin: bleeding risk got it pulled from healthy-elderly advice.
• GLP-1: the early “longevity” wins look like mostly weight loss.

My bet: the first real longevity drug is still unwritten. When a pill adds years to healthy people the way Ozempic drops pounds, that’s the actual Ozempic Challenge. We’re not there yet.

Full writeup with the studies: https://www.unaging.com/aging/the-ozempic-challenge-for-longevity-drugs/