Evidence Level
Hemp seed oil research focuses on its unique fatty acid profile — particularly the 3:1 omega-6 to omega-3 ratio and GLA content. Callaway et al. (2005) published the most cited clinical trial in the Journal of Dermatological Treatment, a 20-week crossover RCT showing dietary hemp seed oil significantly improved atopic dermatitis symptoms including dryness, itchiness, and need for medication, compared to olive oil control. The mechanism involves GLA conversion to DGLA, which competes with arachidonic acid in COX/LOX pathways. Schwab et al. (2006) demonstrated favorable changes in plasma fatty acid profiles and cholesterol ratios with hemp seed oil supplementation. Deferne & Pate (1996) characterized the complete fatty acid profile of hemp seed oil, establishing its optimal omega-6:omega-3 ratio and GLA content. The evidence base is smaller than for fish oil or flaxseed oil, with most studies being small-scale. However, the unique combination of balanced omega ratios, GLA, and complete amino acid content makes hemp seed oil a distinctive plant oil worthy of further clinical investigation, particularly for dermatological conditions.