Seed Oils: Addressing the Controversy

Seed oils have become an increasingly hot topic. As demand has grown for clean, natural and effective products, oils extracted from grape, sunflower, safflower and pumpkin seeds, among others, have dominated many botanical skincare formulations. However, on the heels of their rising popularity, controversy has recently been stirred up around these oils with dietary claims about toxicity, inflammation and disease risk. I've even had people ask if our skincare products contain seed oils while vending at the farmers' market, so I figured it was time to research them again. In this article, we’ll explore what seed oils are, how they’re used in skincare, what the scientific evidence from nutritional/health research says (and doesn’t say) about them, how cultivation and processing matter, and how to navigate the chatter with an informed lens.

 

What are seed oils and how are they used in skincare?

“Seed oils” generally refer to vegetable oils extracted from the seeds of plants (rather than fruits, nuts or animal-derived sources). In the nutrition discourse, those making claims often point to the “hateful eight” oils: canola (rapeseed), soybean, corn, cottonseed, sunflower, safflower, rice bran and grapeseed.

In skincare, seed oils have several attractive qualities:

• Many are rich in polyunsaturated fatty acids (PUFAs) or monounsaturates that support the skin’s lipid barrier, help retain moisture and reduce transepidermal water loss.
• They often contain vitamins (e.g., vitamin E and carotenoids), phytosterols, and other components that exert antioxidant or anti-inflammatory effects.
• They are relatively lightweight and often have a low comedogenic rating compared to heavier oils that can clog pores for some skin types (e.g., coconut oil and tallow).
• They can be derived from certified organic seeds, enabling plant-based and vegan-friendly formulations that benefit the biodiversity of the soil.

So from a skincare standpoint, using seed oils is compelling. But their efficacy and safety also depend on which seeds, how they were grown, how they were processed, and how they are formulated into the final product.

 

Nutrition Research Meets Social Media

While seed oils are popular and widely used, they have been caught in a storm of claims and counter-claims. Below are the main points of controversy:

Claims of Harm

Critics (including wellness influencers and some political figures) argue that because many seed oils are high in omega-6 fatty acids, they drive chronic inflammation, which in turn fuels conditions such as heart disease, diabetes, obesity and autoimmune disorders.

Some point to industrial-scale extraction methods (e.g., use of hexane solvent, high heat and refining) as introducing harmful compounds or reducing beneficial nutrition.

Pushback 

On the flip side, many nutrition science experts say that the evidence does not support a blanket condemnation of seed oils. For example:

• A piece from the Bloomberg School of Public Health at Johns Hopkins University concludes: “There is abundant evidence suggesting that seed oils are not bad for you. If anything, they are good for you.”(7)
• Meta-analyses and randomized controlled trials have found little to no effect of seed oil (or their main fatty acid, linoleic acid) consumption on key inflammation markers.(8)
• The American Heart Association supports replacing saturated fat with unsaturated plant-based oils (which include many seed oils) for cardiovascular risk reduction.(10)

The Middle Ground

Some authors offer a more cautious take: while seed oils seem safe and may even offer benefit, the science is not fully definitive, especially when it comes to high consumption in modern dietary environments. For instance, a commentary in STAT News states:

“The uncomfortable truth: The scientific community has not definitively determined the health effects of high seed-oil consumption.”(11)

Thus the controversy arises from a mix of:

• Science that supports benefit in many contexts
• Popular claims that exaggerate risk
• Public perception that often overlooks nuance
• Real gaps in long-term, high-quality, causally-definitive studies

 

Three Key Questions

Do seed oils promote inflammation?

This is arguably the central contention. The argument of critics: seed oils → high omega-6 → shift in omega-6:omega-3 ratio → more pro-inflammatory eicosanoids → chronic inflammation. However:

• According to recent reviews, human intervention trials have not consistently found elevated markers of inflammation when seed oil consumption increases.(8)
• Johnston Marklund (in the Bloomberg/Johns Hopkins piece) states that higher levels of linoleic acid (the main omega-6 in many seed oils) are associated with lower risk of type 2 diabetes and cardiovascular disease in some cohort analyses.(7)
• Yet, some nuance: variation in individual metabolism (e.g., different genetic backgrounds) may modulate how omega-6 PUFAs affect inflammatory pathways.(9)

Takeaway: The theoretical inflammation mechanism is plausible, but real-world human evidence does not uniformly support the idea that seed oils cause systemic inflammation.

Are the extraction and refinement methods concerning?

Conventional seed oils undergo industrial refining: cleaning, mechanical/solvent extraction (often hexane), degumming, neutralization, bleaching and deodorization. Concerns have been raised about residual solvents, oxidation (due to high heat or repeated frying), trans isomer formation and off-flavors or compounds of unknown biological activity. Some key points:

• Although hexane is used during extraction, regulatory standards are said to ensure minimal residues. However, many find the notion of any hexane residue unsettling.
• Overheating or re-use of oil (especially in industrial frying) may produce degraded lipids or harmful compounds; but this applies to many oils, not purely seed oils.(8)

Takeaway: The refinement and extraction practices merit attention (especially for ultra-processed applications), but aren’t sufficient to declare seed oils inherently “toxic" in and of themselves.

What about cardiovascular/metabolic outcomes?

This is where the link with nutrition dominates, but it is relevant for systemic health which indirectly affects skin too (e.g., via inflammation, oxidative stress and insulin resistance). Some findings:

• Seed oils contain unsaturated fats, which, when replacing saturated fat, are associated with reduced LDL-cholesterol and lower cardiovascular risk.(10)
• The Bloomberg/Johns Hopkins piece reports that participants with highest linoleic acid levels had a ~35% lower risk of developing type 2 diabetes in one sample.(7)
• However, as noted, some researchers argue that despite positive surrogate outcomes (cholesterol, markers) the long-term causal evidence in why/how seed oil consumption across populations affects chronic disease remains incomplete.(11)

Takeaway: Evidence leans toward seed oils being a better choice (in many contexts) compared to saturated fats, but the big picture (especially in real-life dietary patterns) is more complex than the “good vs. bad oil” dichotomy.

 

Implications for Skincare

Although most of the controversy has centered on ingestion and systemic effects, several lessons carry over into skincare formulation and consumer choice:

Quality and Processing Matter

• Seed oils that are cold-pressed or minimally refined retain more beneficial compounds (vitamins, phytosterols and antioxidants) and no processing-derived impurities.
• Oils from organically grown seeds ensure lower pesticide/residue load and healthier seed nutrient profiles.
• Overheated or highly processed oils may have degraded lipids or oxidized compounds that could irritate the skin or contribute to oxidative stress.

Fatty Acid Profile and Skin Barrier Support

• Seed oils rich in linoleic acid (an omega-6 PUFA) help support the skin’s ceramide structure and barrier integrity. Many dermatology sources emphasize that linoleic acid is essential for epidermal lipids and reducing transepidermal water loss.
• Balancing seed oils with oils rich in omega-3s, monounsaturates (oleic acid) or more stable lipids (e.g., argan, macadamia and olive) might be beneficial in formulations to provide a mixture of nourishing lipids and reduce oxidation risk.

Context of Use: Formulation and Stability

• How seed oils are formulated (addition of antioxidants, packaging to protect from light/oxygen and avoidance of repeated heating) influences their performance and safety.
• Topical use is different from dietary use: oxidative products that might be problematic internally may or may not behave similarly on the skin, but guarding against rancidity/oxidation is still good practice.

Holistic Health: Seeing the Big Picture

• When looking at skin health, systemic nutrition and topical skincare interplay: a diet high in ultra-processed seed oil may affect systemic inflammation, insulin resistance or oxidative stress, which in turn can manifest in skin conditions (acne, premature aging and wound healing).
• Thus when formulating or selecting skincare, it helps to consider the broader lifestyle: diet, antioxidant status, UV exposure, smoking, sleep and so on.

 

How We Select Our Seed Oils

What we do as a sustainable skincare brand:

• We check the seed oil’s origin: First and foremost, is it certified organic? This means the seeds are grown in nutrient‐rich soil that benefits the environment and can positively impact the nutrient content of the plant. Additionally, certified organic seeds are non-GMO.
• We check the extraction process: certified organic oils cannot be extracted using hexane. If a certified organic oil needs to be refined for stability and clarity, natural processing aids like diatomaceous earth are used. Most of the oils we use are cold-pressed, while some seeds must be expeller-pressed, which is simply using a screw press to extract the oils. We do not use any solvent extracted seed oils. All of these attributes make the oils we source more beneficial and more expensive.
• We formulate for stability: we avoid exposing the oil to excessive heat/light/oxygen, include antioxidants and package in amber glass.
• We balance our lipid portfolio: We don’t rely exclusively on high-linoleic seed oils (our sunflower oil is even high-oleic for a longer shelf life), and include oils with various fatty acid profiles to create synergy.

 

Navigating the Chatter

Seed oils are no longer a niche ingredient; they’re everywhere. The scientific evidence tilts in favor of them being, in many contexts, safe and beneficial, especially when used to replace more harmful fats (in diet) or when formulated carefully (in skincare). However, the bold claims that they are toxic, inflammatory, or unequivocally bad are not supported by the balance of current evidence. Meanwhile, the nuance: that growing and extraction method, seed quality, oxidation status, dietary context and genetics all modulate outcomes, is often lost in public discourse.

For skincare specifically, selecting seed oils from organically grown, minimally processed sources makes sense. For overall health and skin health, focusing on whole diet quality, minimizing ultra-processed fats, protecting oils from oxidation, and maintaining balance (both in fats and in lifestyle) remains more important than demonizing or glorifying any single oil.

In short: seed oils can be allies when chosen and used wisely.

 

References

1. Lin, T. K., Zhong, L., & Santiago, J. L. (2017). Anti-inflammatory and skin-barrier-repair effects of topical application of some plant oils. International Journal of Molecular Sciences, 18(11), 2443. View Study
2. Blin, C. et al. (2025). Influence of vegetable oils and their constituents on in vitro human skin barrier. Scientific Reports, 15, 9711. View Study
3. The Role of Linoleic Acid in Skin and Hair Health: A Review. (2025). International Journal of Molecular Sciences. PMC11719646. View Study
4. Narang, A. et al. (2025). Mechanistic insights and clinical evidence of Helianthus annuus (sunflower) seed oil. Phytotherapy Research. PubMed 40783675. View Study
5. Blume-Peytavi, U. et al. (2022). Optimised emollient mixture for skin barrier repair: Applications to global child health. Journal of Global Health, 12, 03019. View Study
6. Cooke, A. (2023). Skin-barrier benefits of sunflower seed oil. Dermatology Times. View Article
7. Johns Hopkins Bloomberg School of Public Health. (2025). The evidence behind seed oils’ health effects. Read Source
8. WUSF Public Media (NPR). (2025, July 7). Are seed oils actually bad for your health? Here’s the science behind the controversy. Read Article
9. PBS NewsHour. (2025). Are seed oils toxic? The answer is complicated, according to research. Read Article
10. Harvard Health Publishing. (2025). Seeding doubt: The truth about cooking oils. Harvard Heart Letter. Read Article
11. STAT News. (2025, May 20). The scientific community has not definitively determined the health effects of high seed-oil consumption. Read Article
    

 

Written in collaboration with artificial intelligence. Edited by a human.