I’m posting this because there is a significant gap between clinical guidelines and the anecdotal "systemic" side effects some users experience with topical tretinoin. While dermatologists often focus on localized irritation (redness/peeling), my experience suggests that for some, the response is entirely internal. I’m curious if anyone else has navigated this "toxic" feeling or navigated it with their physician.

The Observation: Beyond Localized Irritation

When I apply tretinoin, I don't just experience skin peeling; I experience a severe systemic response characterized by intense vertigo and physical exhaustion that can last for days. Interestingly, I have observed the same response with almond oil, which is often used as a carrier in skincare.

I’ve identified two critical factors that dictate the intensity of this response:

1. The "Wet Skin" Variable: Applying product to damp skin or a recently exfoliated barrier significantly amplifies the internal symptoms.
2. Mitigation via Removal: If I wash the product off (showering) shortly after the onset of these symptoms, the recovery window is drastically shortened.

The Scientific Context

While many practitioners dismiss systemic absorption as "minimal," the research confirms that transdermal bioavailability is not a fixed number—it is highly dependent on skin state and vehicle.

• Hydration & Permeability: Research into transdermal delivery systems confirms that moist skin hydrates and relaxes the stratum corneum, which significantly improves drug absorption into the bloodstream (Sivadasan & Madkhali, 2024). This explains why applying tretinoin to wet skin or a compromised barrier can shift it from a localized treatment to a systemic one.
• Systemic Toxicity Markers: The symptoms of lethargy, headache, and dizziness are established markers of Hypervitaminosis A (systemic retinoid toxicity) (Bremner, 2012). While usually associated with oral doses, individual variations in percutaneous absorption can lead to varying levels of systemic exposure (Lehman et al., 1988).
• Cumulative Sensitization: My theory is that this is a form of cumulative sensitization. This phenomenon is well-documented with other topicals, such as p-Phenylenediamine (PPD) in hair dyes, where the body develops a delayed-type hypersensitivity or systemic immune response after repeated exposure (Lee, 2026; SCCP, 2000).

Community Inquiry

Because the medical literature on "topical-to-systemic" toxicity is limited, I’m looking for others who have experienced:

• Non-dermatological symptoms (dizziness, "flu-like" fatigue, or vertigo) shortly after application.
• A clear correlation between barrier health (post-exfoliation or wet skin) and the onset of internal symptoms.

Is it possible that "sensitive skin" is sometimes actually a high-efficiency transdermal bypass?

References

Bremner, J. D. (2012). Retinoic acid and affective disorders: The evidence for an association. Journal of Clinical Psychopharmacology, 32(2), 1-15.https://pmc.ncbi.nlm.nih.gov/articles/PMC3276716/Cited by: 301

Lee, J. J. (2026). Para-phenylenediamine sensitization and polysensitization: TNF-α, CXCL11, and immune-regulatory gene polymorphisms. Clinical and Experimental Dermatology, 51(1), 1-10.https://pmc.ncbi.nlm.nih.gov/articles/PMC12505369/

Lehman, P. A., Slattery, J. T., & Franz, T. J. (1988). Percutaneous absorption of retinoids: Influence of vehicle, light exposure, and dose. Journal of Investigative Dermatology, 91(1), 56-61.https://doi.org/10.1111/1523-1747.ep12463289Cited by: 134

Scientific Committee on Consumer Products (SCCP). (2000). Opinion on p-Phenylenediamine. European Commission.https://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_069.pdf

Sivadasan, D., & Madkhali, O. A. (2024). The design features, quality by design approach, characterization, therapeutic applications, and clinical considerations of transdermal drug delivery systems—A comprehensive review. Pharmaceuticals, 17(10), 1346.https://doi.org/10.3390/ph17101346Cited by: 52