Omega-7 (Sea Buckthorn): What Research Says About Skin and Mucous Membranes

Everyone knows Omega-3 and Omega-6, but in recent years, a less famous fatty acid has been gaining interest: Omega-7. Its scientific name is palmitoleic acid, and it is a monounsaturated fatty acid that our body can also produce in small amounts, but it is also found in food and supplements. Its prominent plant source is sea buckthorn oil, a small orange-red fruit that grows in cold climates, as well as macadamia nuts. There are also supplements of purified palmitoleic acid.

What makes Omega-7 interesting is precisely the direction in which it is being studied. While Omega-3 is associated with the heart and brain, Omega-7 and sea buckthorn oil are mainly studied around dryness of mucous membranes: dry eyes, dry skin, and vaginal dryness. This is an unexpected direction, stemming from the role of this fatty acid in cell membranes and the lipid layers of body tissues. In this article, we will explain what Omega-7 is, how it works, what the evidence actually shows, and why we decided to rate it yellow, meaning promising but not yet sufficiently established.

What is Omega-7?

Omega-7 is a family of monounsaturated fatty acids, the most prominent of which is palmitoleic acid. Here is what is important to know about it:

• It is a monounsaturated fatty acid. Unlike Omega-3 and Omega-6, which are polyunsaturated and essential (the body cannot produce them), palmitoleic acid is monounsaturated, and like olive oil, the body can produce it to some extent on its own.
• Its main plant source is sea buckthorn oil. The sea buckthorn fruit, especially its pulp oil, is rich in Omega-7 and carotenoids. This is the source on which most clinical research has been conducted.
• It is also found in macadamia nuts and certain fish. Macadamia is one of the richest sources of palmitoleic acid among nuts.
• It also exists in purified form. Some supplements offer purified palmitoleic acid (usually from fish or plant sources), which contains a high percentage of Omega-7 and fewer other fatty acids.

An important point for the consumer: Sea buckthorn oil contains much more than just Omega-7. It is a mixture of fatty acids (including Omega-3, Omega-6, and Omega-9), carotenoids, vitamin E, and phytosterols. Therefore, when discussing sea buckthorn studies, it is difficult to isolate how much of the benefit comes from Omega-7 itself and how much from the other components. A purified palmitoleic acid supplement, on the other hand, isolates Omega-7, so it is advisable to choose a product that honestly declares its palmitoleic acid content and not just the general term Omega-7.

The Connection to Dryness and Mucous Membranes: The Mechanism

To understand why dryness specifically, one must think about what a fatty acid does in tissue. Cell membranes are partly composed of fats, and fatty acids are also the building blocks of the lipid layer that protects the skin and mucous membranes from moisture loss. When the tissue is deficient in appropriate lipids, it loses water more quickly and feels dry.

Sea buckthorn is rich in fatty acids that participate in building the lipid barrier of the skin and mucous membranes. The leading hypothesis is that oral intake of sea buckthorn oil provides the body with raw materials that improve the protective lipid layer, thus reducing water loss from the skin, eyes, and other mucous tissues. This is very different from a supplement intended to provide energy or alter a metabolic pathway, and it explains why the most documented benefit is in the area of dryness.

In another direction, researchers have examined Omega-7 as a metabolic signaling molecule. In laboratory and animal studies, palmitoleic acid has been described as a "lipokine," meaning a fatty acid that acts as a messenger between adipose tissue, the liver, and muscle, and may affect insulin sensitivity and inflammation. It is important to qualify immediately: most of these data are preclinical (laboratory and animal), and the leap from them to humans is far from guaranteed.

Current Evidence

Study 1: Sea Buckthorn Oil and Dry Eyes, Larmo et al. 2010

This is the most established human study on Omega-7 and sea buckthorn. In 2010, Larmo et al. published in the Journal of Nutrition a double-blind, randomized, placebo-controlled trial examining the effect of sea buckthorn oil on dry eyes. The trial recruited 100 men and women aged 20 to 75 who suffered from dry eye symptoms, of whom 86 completed the trial.

Participants took 2 grams of sea buckthorn oil or placebo oil daily for 3 months, from autumn to winter, the period when dry eyes typically worsen. The result: in the sea buckthorn group, tear osmolarity (a measure of tear film stability) was more stable, and scores for dryness symptoms, redness, and burning were lower compared to placebo. The effect was moderate, not a cure, but measurable and consistent. This is the highest quality evidence we have that oral sea buckthorn can genuinely help with mucous membrane dryness.

Study 2: Skin and Vaginal Mucosa, Preliminary Data

The same research group and others expanded the examination to other dry tissues. Small studies tested oral or topical sea buckthorn oil on skin moisture, skin barrier (transepidermal water loss), and vaginal dryness, reporting moderate improvement in tissue moisture and softness. A later work, a controlled trial published in 2023 examining the broad effect of oral sea buckthorn oil on skin, blood markers, and eye and vaginal health, continued this line and documented improvements in some measures.

The caveat here is important: These are relatively small studies, some on whole sea buckthorn oil and not isolated Omega-7, so they are promising but far from a definitive conclusion. Still, they paint a consistent picture: if you have a chronic mucous membrane dryness problem, sea buckthorn is a reasonable candidate for a trial, especially when alternatives are few.

Study 3: Palmitoleic Acid and Metabolic Markers, Bernstein 2014 (Important Caveat)

In the metabolic direction, the most cited study is by Bernstein et al. In 2014, a double-blind, randomized, placebo-controlled trial was published in the Journal of Clinical Lipidology on 60 adults with dyslipidemia and mild inflammation (CRP between 2 and 5), who took 220.5 mg of purified palmitoleic acid or placebo daily for 30 days. The trial reported significant reductions in CRP, triglycerides, and LDL, and an increase in HDL.

And here honesty is required: This article was retracted (withdrawn) due to doubts about the statistical analysis, as the magnitude of the reported changes did not match the expected variability of blood lipid markers. In other words, the impressive metabolic results sometimes marketed around Omega-7 rest on weak and controversial evidence. A later trial on an Omega-7 blend even found no reduction in blood inflammatory markers. Therefore, regarding the heart, cholesterol, and blood sugar, Omega-7 is only preliminary, not proven.

What About Omega-3? Don't Replace, Supplement

A common mistake is to think Omega-7 competes with Omega-3, but they fulfill completely different roles. Omega-3 (DHA and EPA) is an essential fatty acid with strong evidence for heart, brain, and eye health, and there is no reason to replace it. Omega-7, on the other hand, is a niche: it is mainly studied for mucous membrane dryness, an area where Omega-3 has much less focused evidence.

In other words, if you are deciding between the two, Omega-3 should be the foundation, and Omega-7 can be a targeted addition for a specific dryness problem. The two can coexist, and there is no known conflict between them. In fact, part of the benefit of sea buckthorn for dry eyes may also come from its Omega-3 content, which is another reason not to see them as rivals.

Should You Start Taking Omega-7?

We rated Omega-7 yellow, meaning promising but with early and small evidence, so the recommendation depends heavily on what you are looking for. Here are the considerations:

• For mucous membrane dryness, there is a reasonable basis to try. The Larmo 2010 study on dry eyes is a genuine randomized controlled trial, and even if the effect is moderate, it exists. For those suffering from dry eyes, skin, or mucosa, this is a logical option for a controlled trial of a few months.
• For metabolic markers, do not expect a miracle. The evidence on cholesterol, triglycerides, and inflammation rests mainly on a retracted study, and another trial found no benefit. Do not buy Omega-7 as a substitute for blood lipid treatment.
• Safety is generally good. Omega-7 and sea buckthorn oil are well-tolerated. Common side effects are mild, mainly minor digestive discomfort.
• Pay attention to product quality. Since "Omega-7" is a marketing term, choose a product that declares the actual percentage of palmitoleic acid, not just the keyword.

Despite good safety, there are some cautionary points. Sea buckthorn oil has a mild blood-thinning effect (slight slowing of clotting), so those taking anticoagulant medications like warfarin or regular-dose aspirin, or facing surgery, should consult a doctor before use. Additionally, pregnant and nursing women, people with chronic medical conditions, and anyone on regular medications should consult a doctor about the appropriate dosage. Dry eyes or chronic dryness can be a symptom of an underlying medical condition (such as gland disease, Sjögren's syndrome, or a medication side effect), so persistent dryness requires medical evaluation, not just a supplement.

What to Take Away from the Research?

1. If you suffer from dry eyes, skin, or mucosa, Omega-7 is worth a trial. This is one of the few areas where there is a randomized controlled trial (Larmo 2010), even if the effect is moderate. Try for a few months and see if there is improvement.
2. Do not buy Omega-7 for cholesterol or blood sugar. The metabolic evidence is weak and controversial. For blood lipids, Omega-3, diet, and physical activity are the proven foundation.
3. Keep Omega-3 as the foundation. Omega-7 complements, not replaces. First ensure adequate Omega-3 intake, then consider Omega-7 for a targeted problem.
4. Choose a transparent product. Look for declared palmitoleic acid content, preferably sea buckthorn pulp oil which is richer in Omega-7, or purified palmitoleic acid.
5. If dryness persists, see a doctor. Chronic dryness can indicate a medical condition, and a supplement should not replace diagnosis. If you are on blood thinners or facing surgery, consult before use.

For those who want to try, you can purchase Omega-7 (sea buckthorn oil) on iHerb in various preparations and potencies. To check which supplements are suitable for your health goals, including skin and mucous membrane health, based on your age and condition, you can use our personal supplement checker that rates each supplement according to evidence quality.

The Broader Perspective

Omega-7 is an excellent example of what we try to do on this site: separate what the research actually supports from what marketing promises. Around Omega-7, a rosy picture is sometimes marketed of a supplement that lowers cholesterol, reduces inflammation, and improves metabolism, but when examining the evidence in depth, one finds that the metabolic direction rests on a retracted study, while the real and documented benefit lies in a more modest corner: mucous membrane dryness.

The lesson is twofold. First, Omega-7 is a reasonable niche supplement: for those suffering from dry eyes, skin, or mucosa, there is a reasonable basis to try it, understanding that the effect is moderate and not dramatic. Second, and more importantly, no single fatty acid is magic. Skin and tissue health, like heart and brain health, is built from a complete pattern of balanced nutrition, adequate hydration, sleep, sun protection, and inflammation management, and Omega-7 can be a complementary component but not a central one. And that is precisely the angle we hold: to rate each supplement according to what science actually shows, and to honestly say when a supplement is promising but early, like Omega-7, and when it is just a promise.

References:
Larmo PS. et al., Oral Sea Buckthorn Oil Attenuates Tear Film Osmolarity and Symptoms in Individuals with Dry Eye, The Journal of Nutrition, 2010;140(8):1462-1468 (DOI: 10.3945/jn.110.118901)
Bernstein AM. et al., Purified Palmitoleic Acid for the Reduction of High-Sensitivity C-Reactive Protein and Serum Lipids (WITHDRAWN), Journal of Clinical Lipidology, 2014;8(6):612-617 (DOI: 10.1016/j.jacl.2014.08.001)